Plant Recolonization and Vegetation Succession on the Krakatau Islands, Indonesia
R. J. Whittaker; M. B. Bush; K. Richards
Ecological Monographs, Vol. 59, No. 2. (Jun., 1989), pp. 59-123.
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t.~o/o~ri.u/.Ifonographs. 59(2). 1989. p p 59-123
i 1989 b) the Ecolog~calSoc~et)of Amenca
PLANT RECOLONIZATION AND VEGETATION 

SUCCESSION ON THE KRAKATAU ISLANDS, INDONESIA1 

R. J. WHITTAKER
School of Geograph~, C nrrersrt~o f Ouford, .Mansfield Road, Ouford, OX1 3TB, C nrted Krngdom
M. B. BUSH'
Dcpartrnent o f Geographl L n ~ ~ e r s ~ t lo f Hull, Cottrngham Road, Hull, HC'6 7R.Y, Y,nLted Klngdorn
AND
K. RICHARDS
Robertson Research Internatronal, Llandudno, Gwl nedd, LL30 1S;1 Lnrted Krngdorn
.Abstract. The development of the vegetation and floras of the Krakatau Islands in the Sunda Straits,
Indonesia. since their "sterilization" in 1883 is described. Key features of the post- 1883 environment. such as
pedogenesis, geomorphology (coastal change), human influence. and recent volcanic activity are detailed, and
their possible influence on spatial and temporal patterns in both vegetation and flora is discussed.
Field work conducted in 1979. 1983, and 1984 has enabled an assessment of the present state of vegetation
development. aided by plot-based sampling and analysis of the arboreal component. employing numerical
classification (by TWINSPAN) and ordination (by DCA). The coastal communities were established early and
have remained little changed, although the distribution of the various components has changed according to
the influence of a dynamic coastal geomorphology. Fifty years after forest closure. the forests of the interiors
remain species-poor and composed of typical early-sera1 species. Rakata was dominated inland by A'eonauclea
calyclna and Ficus pubinervis up to ~ 5 5 0m altitude, above which a mossy forest of Ficus spp. and Scheflera
poljlbotrya scrub was recorded. The main inland forest types on Rakata Kecil and Sertung were of young, evenaged
stands of Tilnonius compressicaulis (extensive) and older stands of Dyso.xj~/urngaudichaudianum (often
with a T. compressicaulis understory). The principal axes of variation within the data were found to be between
extremes of the Rakata forest types. with Sertung and R. Kecil stands remaining undifferentiated until lower
levels of the analyses. These patterns were ascribed to a mix of environmental variation (coastal and altitudinal
factors). chance variations in colonization. and to volcanic action following the emergence of Anak Krakatau
in 1927. Disturbance by volcanism (e.g.. in 1930. 1934-1936, 1939, 1952-1953, 1961) has resulted in the
deflection of vegetation succession on R. Kecil and Sertung into a different pathway from that followed on
Rakata. which has remained unaffected by the activity. On Anak Krakatau, volcanic action has prevented
successful colonization away from accreting coastal deposits. and has several times eliminated the entire flora.
In addition, the major source of propagules for Anak Krakatau is from within the group, and for these several
reasons the new island is shown to be a poor analogue for the early recovery phases of the other islands.
Complete floral lists are given for each recorded survey for each island in the group, including data from
surveys in 1979, 1982, and 1983. These data have been revised from previous publications on the basis of
recent herbarium work and literature searches. The data are analyzed according to several different models:
cumulative species totals, species totals for particular combinations of surveys, and totals calculated on the
assumption of minimum turnover. The early beach spermatophyte assemblages of Rakata have undergone
relatively few losses in comparison to the assemblages of the interior. while within the latter there has been a
relatively high proportion of losses among the pioneering pteridophytes. The possession of major habitat types
has been identified as critical in determining the shape of the overall colonization curve. through the passive
sampling of different source pools. The diversity of the floras of the group as a whole and of Rakata and Anak
Krakatau has continued to increase. The curves of species present on Sertung and R. Kecil have levelled and
fallen respectively, as a result of the volcanic activity of Anak Krakatau.
It is shown that the number of animal-transported species on the Krakatau group has continued to increase
over the last 50 yr, and that this accounts for the majority of the increase in the size of the spermatophyte flora.
The animal-transported species and the early sea-dispersed species appear to be species-stable groups. Later
sea-dispersed species included ephemerals and species of temporary habitats, and have experienced a relatively
high proportion of losses. Few beach species that have established on all of the three main islands have
subsequently become extinct from the group. The number of pteridophytes on the islands has increased over
the last 50 yr. mainly through the addition of forest species. A large proportion of plant species has been found
only on Rakata, which samples an upland source pool not represented on the other islands. It is argued that
the assumptions of "classical" island biogeography are inappropriate to these data and that the pattern in floral
recolonization can best be understood as a successional process involving broad habitat and dispersal mechanism
determinants. The implication of these findings is that community dynamics are highly significant in determining
rates of immigration, colonization (i.e., successful immigration), and extinction, and that the probabilities of
each vary among different groups of species and through time.
Kej. words: distz~rbance;rsland blogeographj,;Krakatau;plant recolonrzat~on;tropical,forest: vegetation succession; volcano.
Manuscript received 29 May 1987: revised 6 June 1988: accepted 13 June 1988. 

Present address: Department of Zoology. The Ohio State University. 1735 Neil Avenue. Columbus. Ohio 43210 USA. 

I
R. J. WHITT
INTRODUCTION
The Krakatau (Krakatoa) islands (Fig. 1) have been
the subject of a unique combination of long-term studies
on tropical succession and of studies of the re-assembly
of island biotas. Despite the objections of Backer
(1929. 1930). the sterilization of the islands by the
eruptions of May to 27 August 1883 can be assumed
to be essentially complete. Certainly no significant vestige
of the former soil and vegetation cover remained
on the greatly re-shaped and ash-covered islands (Verbeek
1885, Steenis 1930, 1931. Docters van Leeuwen
1936). The principal sera1 sequences can therefore be
viewed as primary successions. This paper reports a
comprehensive spatial description of the vegetation of
the islands of the group up to 1983-1984, requiring
new interpretations of successional pathways and of
the role of disturbances. The floral recolonization data
are examined with a critical view to the relevance of
island biogeographical theory (sensu MacArthur and
Wilson 1967). with the analysis being directed toward
an understanding of the influence of habitat type,
changing environment, and succession on the patterns
in the floristic data.
The largest island of the group, the remnant from
the active volcano of 1883, is Rakata (Pulau Rakata
Besar. or Krakatau). The other pre- 1883 islands are
Sertung (Verlaten Island) and Rakata Kecil (Lang Island,
or Panjang). A new volcano, Anak Krakatau.
established in the center of the group between 1927
and 1930,and has since grown to become a substantial
island. It adds an extra dimension to this "natural experiment."
both by creating new habitats and by disrupting
the vegetation of Sertung and R. Kecil.
This paper details the first comprehensive description
of the flora and vegetation of the Krakatau islands
since the work of Docters van Leeuwen (1936), integrating
results of investigations in 1951-1 952, 1979,
and 1982-1 984 (Borssum Waalkes 1960, Flenley and
Richards 1982.Tagawa 1984.Tagawa eta!. 1985. 1986,
Bush et al. 1 9 8 6 ~ ) .
PHYSICALENVIRONMENT
Climate
Few meteorological data are available from Krakatau.
although from readings taken on R. Kecil in 1929.
the mean monthly temperature was found to be almost
constant throughout the year. varying from 26.9" (July
and December) to 28.7OC (October), (Fig. 2A: Baren
1931).The climate has been classified as "Afa" in the
Koppens world system, i.e.. as a tropical rainy climate
with few d n months (Subagio and Reuler 1985), with
the west monsoon bringing heavy rains from the Indian
Ocean and the east monsoon relatively d n air from
Australia (Dammerman 1948). The dry season, between
May and October. is of variable duration and
timing, and can be extreme (Fig. 2A).
A series of temperature and humidity readings was
AKER ET AL. Ecological Monographs
Vol 59. No. 2
taken on Rakata in September 1979 (Fig. 2B; Forster
1982).The lapse rate of mean annual air temperatures
was calculated to be 0.8"C/100 m from the regression
line of soil temperatures at 75 cm depth, according to
the method of Mohr and Baren (1954). Personal observation
suggests that the highest altitudes on Rakata
experience a much greater diurnal range in temperatures
than the lowlands, although this has not been
quantified. The gradient in relative humidity at 1300
(Fig. 2B) indicates a fall from about 95% at the summit
to 75-80°/o in the lowland, and a further decline from
the forest to the beaches (Forster 1982). Gradients in
precipitation are doubtless associated with the humidity
and temperature patterns (Borssum Waalkes 1960),
so rainfall may be anticipated to be higher on Rakata
(highest point >735 m) than on Sertung (182 m) or R.
Kecil (142 m).
Caldera development
Verbeek (1885) described the development of the
Krakatau caldera from a prehistoric volcano at least
2000 m high, formed along the Sunda Fault. This volcano
collapsed e 6 0 000 yr ago (Ninkovich 1979, Camus
and Vincent 1983)to form a caldera wall of which
four pieces emerged above sea level. Subsequently from
Rakata peak and the craters Danan and Perboewatan.
the main island rebuilt towards the center of the caldera.
Eruptions of Perboewatan in May 1680 resulted
in the ejection of pumice and possibly of lava. Contemporary
accounts describe the island as "burned and
barren" (Berg 1884). The volcano remained dormant
until 20 May 1883,when Perboewatan and later Danan
became active. After eruptions of increasing violence.
there occurred the catastrophic collapse of 27 August.
repeating the prehistoric collapse. The eruption terminated
on 28 August. although further minor activity
took place in September or October of that year (Verbeek
1885). The ~slandsremained dormant until June
1927 (Simkin and Fiske 1983).
Coastal changc srncc. 1883
The 1883 coastlines of pyroclastic deposits have been
subject to continuous reshaping (Docters van Leeuwen
1936. Dammerman 1948) and have retreated by as
much as 2.5 km, the most extensive recession being in
southwest Sertung and west Rakata (Bird and Rosengren
1984). Rates of recession in these deposits, at 6.6
m/yr. are among the most rapid recorded worldwide.
As a result of the predominant monsoon pattern, wave
action is generally stronger from a westerly direction.
This has resulted in higher cliffs than found on eastern
shores, with incised gullies emerging as v-shaped
notches in the upper cliff. In places the more resistant
underlying rocks (of pre- 1883 age) have been exposed,
as on the southwest coast of R. Kecil, where andesitic
lavas form a structural bench (Bird and Rosengren
1984). The cliffs of the west coast of R. Kecil receded
by as much as 1.5km between 1883and 1928,although
June 1989 RECOLONIZATION A N D SUCCESSION O N KRAKATAU
Flc;. I. The location of the Krakatau Islands. Indonesia.
The 1983 coastline (- - - ) of Rakata Kecil coincides with
the coastline as of this writing (-) except in the north-
west.
since the emergence of Anak Krakatau to the west, this
rate has greatly diminished. In contrast, erosion of the
southern end of Sertung is currently extremely rapid
and can reach rates as high as 3.0 m/mo (Bird and
Rosengren 1984).
From the northern end of Sertung there extends a
broad spit nearly 2 km long. fed by longshore drift
along the island. The spit has been subject to continual
change. By a combination of erosion of the western
shore and accretion on the eastern side, the spit has
migrated 1 km eastward, and suffered a 1 km loss of
length between 1945 and 1982 (Bird and Rosengren
1984. Rosengren 1985). These changes have resulted
in the breaching and loss of two small lagoons present
on the spit in the early part of the centun. (Compare
Fig. 1 and Fig. 3.) The eastern side of the promontory
has formed a sheltered bay with a shallow shelving
beach. The western shoreline is steeper as the spit is
being undercut. so that the Casuarina eqz~isetlfoliatrees
appear stilt-rooted. Above the slope the spit is flat and
for 30 m inland is generally littered with pumice and
flotsam. indicating periodic inundation. Overtopping
of the beach at Zwarte Hoek on Rakata (Fig. 1) was
FIG.2. (A)Climate diagram of R. Kecil from observations
b? Stehn in 1919 (after Tagawa et al. 1985). (B) Pattern of
variation in relative humid~t?with altitude on Rakata. (C)
Temperature variation with altitude on Rakata. (B) and (C)
recorded at 1300 in September 1979 (from Forster 1982).
R. KECIL
- RAINFALL
..... TEMPERATURE
O L r r J A L l
J F M A M J J A S O N C
RAKATA
@ 'O01
I ,/
60 /0 400 800
ALTITUDE lml
@ 29
- AIR TEMPERATURE
0 400 800
ALTITUDE iml
62 R. J. WHITT
RAKATA
1930: Little
1953:Area of damage
.... severe damage 1930:No obvlous
damage
FIG.3. The distribution of volcanic damage on Sertung
in 1930 and 1953. and of the 1919 fire on Rakata. Sertung
has been hit bq eruptive activit? at other points since 1917.
as has R. Kecil. but these events have not been mapped. See
pages 65-66. After Docters van Leeuwen (1936) and De Neve
(personal conlnl~~nication1984).
observed in 1984. with drift being deposited in runnels
behind the strand bank Undercutting of established
trees was noted here as in other places on the islands,
suggesting lateral migration in conditions of erosion
and accretion in the medium term On Anak Krakatau
there ha\ e been a d d ~ t ~ o n sdue to volcan~smand rapld
eroslon of coastlines of pyroclastic materials Where
lava has been extruded on the western coast, the eroslon
rate has been much slower In general. material
drifts to the sheltered eastern coastline of this island,
where cuspate forelands have formed (Bird and Rosengren
1984)
Topograph IC development
The 1883 eruptions resulted in both the removal of
a large part of the main island and the addition of new
territory. The additions took the form of ejecta, a mixture
principally of pumice blocks and fine porous ashes.
The depth of the ash layer in the lowlands appears on
average to have been 60-80 m. although depths of as
AKER ET AL. Ecological Monographs
Vol. 59. No. 2
much as 150 m were reported locally. and the existing
coastlines were extended laterally by as much as 700
m (Verbeek 1885, Docters van Leeuwen 1936, Simpkin
and Fiske 1983). Immediately following the eruption,
the ash was subject to rapid gullying, to the extent
of several metres downcutting by 28 October 1883
(Verbeek 1885).Although the layers of ash and pumice
were not as thick near the summit and were subject to
rapid erosion in the early years. Docters van Leeuwen
(1936) recorded a 5 m depth of 1883 ejecta at a point
on the summit of Rakata as late as 1929.
The islands remain characterized by steeply dissected
topography, with innumerable deep gullies. Slope
instability, landslides, and rockfall have been a continuous
feature of the post- 1883 physical environment
(Docters van Leeuwen 1936, Bush 1986a), although
the deep gully systems characteristic of these islands
represent the product of the intense early post-eruptive
phase of erosion and are now essentially fossil features
(Stehn 1929,Newsome 1982).There is a marked break
of slope on Rakata at -400 m altitude, above which
the dominant topography consists of narrow ridges divided
by deep v-shaped gullies; slopes of 40-70% are
common. Below 100 m, the ridge-gully system is generally
less pronounced, with 25-40% slopes (Subaglo
and Reuler 1985). Small streams flow in some of the
gullies following prolonged downpours, but usually the
porous ash is so permeable that it prevents any surface
flow. Many gullies appear to have become slightly infilled
as a result of slope retreat, with interfluves often
reduced to very narrow ash walls, protected by the
forest cover (Richards 1982).
The north face of Rakata consists of a precipitous
cliff marking the edge of the 1883 caldera (Fig. 4).
Rockfall down this face has been observed frequently
since 1883 (e.g.. Ernst 1908. Docters van Leeuwen
1936). The altitude of the summit was 830 m in October
1883 (Verbeek 1885) and 8 13 m in 1928 (Stehn
1929).Recent survey data are lacking, but photographic
evidence suggests no more than a slight decline since
then. The altimeter readings of 735 m used here must
therefore be viewed as provisional, subject to revision
by proper survey data. The profiles of Sertung and R.
Kecll also slope steeply from the s u m m ~ tridge to the
center of the prehistoric caldera, with more gentle outer
slopes. Although relatively low islands, both are deeply
dissected by gullies which, combined with the sheer
cliffs of the eroding coastlines (Fig. 5). have prevented
exploration of some areas.
Soils
The vitric ash (hypersthene-augite association) of
1883 provided a nutrient-rich substrate and an excellent
rooting medium. Nevertheless, it lacked organic
matter and some minerals may not have been available
in soluble form (Ernst 1908. Baren 1931).The initially
homogeneous ash cover quickly became more varied,
and by 1886, sand and organic debris had become
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
FIG.4. The sheer north face of Rakata (>735 m), viewed from Anak Krakatau (unvegetated foreground) (T. Richards
1983).
mixed with the pumice along the coast. Inland the
larger ravines had cut through the new ash. in places
exposing the older buried material.
By 1979 there was some evidence of weathering in
the form of mineral decomposition and associated cation
release (Newsome 1982. 1986). Particle size data
showed low overall percentages of clays. but there was
evidence of crystalline clay minerals (smectite and traces
of chlorite, vermiculite. and mica). which were attributed
principally to geo-hydrothermal alteration in the
course of the 1883 eruption. Organic matter incorporation
and decomposition at the soil surface has given
rise to well-developed A horizons. especially in more
stable gullies. Subaglo and Reuler (1985) indicate a
solum depth of 20-30 cm. and occasionally as much
as 35-40 cm. but with only thin A1 horizons (2-8 cm).
overlying weak gravelly silt/loam AC horizons. In some
places a B1 or weak B2 horizon could also be distinguished.
Subagio and Reuler (1985) classify these soils
as Typic or Andeptic Troporthents and Eutropepts.
while Shinagawa et al. (1984) classify all seven samples
located between 2 and 730 m on Rakata as Andeptic
Troporthents. The soils of Rakata are highly permeable,
as indicated by a low bulk density of <0.82 g/cm3
and high total pore space (> 69%) (Hardjosoesastro and
Dai 1985. Newsome 1986). Nevertheless. the micropores
of this relatively silt-rich soil have a higher capacity
for water retention and are less subject to desiccation
than, for example, the sand) soils sampled on
the vegetated parts ofAnak Krakatau In 1979 and 1983
(Newsome 1986).
The soils of Rakata also show some variation with
altitude. For example. there is a decrease in the concentration
of sodium in the A horizon with increasing
altitude (Flenley and Richards 1982). although this may
be largely due to the decreasing coastal influence. Above
-530 m altitude. soil organic matter appeared distinctly
black and well decomposed. but mixed with
fibrous organic material. In contrast to the thin. ash)
soils of the lowlands. High levels of calcium in the
topsoil and high carbon/nitrogen values of the upland
soils indicated a mull humus (Newsome 1982). Soils
with buried horizons were estimated subjectively to
cover < 10% of the area in 1982 (Subaglo and Reuler
1985). and were found primarily within the upland
gullies (>400 m altitude). The buried brown soils were
developed from older basalto-andesitic ash. perhaps
related to the 1680 eruption. Compared to the post-
1883 soils. the buried soils displayed more advanced
weathering and appreciable amounts of clay (7-1 5%).
Some had become incorporated into contemporary
so~ls.due to downcuttlng. slumping of gull) sldes and
re-depos~t~onon the lower slopes (Subaglo and Reuler
1985).
Shinagawa et al. (1984) classlfq soils sampled from
Sertung (four sltes). R. Kecll (fi\ e sltes) and Anak Krak-
R. J. WHITTAKER ET AL. Ecological Monographs
Vol 59. No. 2
FIG.5. A high-energy beach environment on Rakata. typical of many of the unsheltered beaches of the islands. This
stceplq shelving eroding beach is unsuitable for pes-caprae establishment and is backed by sheer ash cliffs and hanging gullies.
exposing forest of the interior at the cliff-edge. The stacks, once a part ofthe western portion of Rakata. are now a considerable
distance out to sea (T. Richards 1983).
atau (two sites) as Tlplc (as opposed to Andeptic) Troportht
n[s. The samples from Sertung and R. Kecil were
found to have lower contents of soil organic matter.
clay. and free iron and aluminum hydroxides than those
from Rakata. They describe five or six phases of soil
development. interrupted by deposits of volcanic ash
and scoria originating from Anak Krakatau. These include
very recent deposits in the cases of at least one
profile from both R. Kecil and Sertung (cf. Simkin and
Fiske 1983:359). Carbon. exchangeable and water-soluble
potassium, and clay and silt contents revealed a
gradient from Anak Krakatau soils. which were similar
to those of Sertung and R. Kecil. through to Rakata
soils. Shinagawa et al. (1984) suggest that these variations.
in particular those relating to the ejecta from
Anak Krakatau. could have provided a significant influence
on the patterns of vegetation succession within
the islands.
The soils from Anak Krakatau. developing in coarse
to medium scoria. fragments of lava. or even lapilli.
were the least developed of all those sampled in 1982
by Shinagawa et al. (1984). Newsome (1986) found that
the soils of the vegetated areas were almost entirely
composed of sand-sized particles (>5 0 pm). Formation
of the A 1 horizon has been very weak. with low carbon
exchange capacity. organic carbon, and total nitrogen
(Barker and Richards 1982). The samples taken by
Shinagawa et al. (1984) ranged from pH 6 to 7.3, little
different from the other islands. but Barker and Richards
(1982) reported slightly lower values of pH 5.3 to
6.8 for six near-coastal sites sampled in 1979. The
surface environment on Anak Krakatau is distinct
within the group on account of the lack of a complete
vegetation cover. High surface temperatures and a
macroporous structure render this soil prone to desiccation.
and unsuitable for nonxerophyte coloniza-
tion.
Volcanic and tectonrc actirit,y since IS83
After 1883, no major volcanic episodes occurred unril
1927. when a new cone began to build at the edge
of the 1883 caldera. A permanent presence was estab-
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 65
FIG.6. Sertung following the 1952 eruption. Notes by De Neve on back of photograph: "Sertung, 19th October, 10.30
hrs. Volcanic ash on the broken trees and other vegetation has been washed away by rains. The thickness of new ash at this
localit) c. 40 cm: distance from beach 250 m. (De Neve)."
lished (Anak Krakatau IV) on 12 August 1931. By
September 1932 the island was 47 m high. It has continued
to grow rapidly as a result of successive eruptive
phases (including several lava flows). and in 1985 was
190 m high and 2 km in diameter (Bird and Rosengren
1984. Thornton 1986). The new volcano has directly
affected the other islands of the group by such influences
as wave damage, ash fall, fire damage, gas poisoning,
and earthquakes. Although incompletely documented.
the major recorded events are as follows.
.-lsh.fall and blast damage. -Ash fall and blast damage
are known to have affected Sertung in 1930. 1934,
1935 (Docters van Leeuwen 1936. Dammerman 1948),
1952 (Fig. 6 and Borssum Waalkes 1954. 1960) and
1953 (G.A. De Neve 1953a, b, 1982, personal communication
1984. 1985). Dammerman (1948) recorded
violent eruptions in July 1939 that totally buried
the pioneer vegetation on Anak Krakatau. and there
were eruptions during World War I1 of unknown effect
on the other islands (Borssum Waalkes 1960). It is clear
that R. Kecil received ash fall in the early years of
activity. e.g.,in 1932(Dammerman 1948),and in 1952-
1953(Hoogerwerf 1953,Borssum Waalkes 1960).There
have undoubtedly been other occasions on which Sertung
and R. Kecil have been affected by ash fall (see
Sudrajat 1982), one of the most recent being a light
fall on Sertung in 1981 (Simkin and Fiske 1983:359).
Indeed. in 1982 Shinagawa et al. (1984) recorded five
or six separate layers of post-1883 volcanic ash and
scorias on both islands, including very recent deposits.
Eruptions in 1961 are known to have produced andesitic
lava flows as well as pyroclastic fallout (Bird
and Rosengren 1984). and there were substantial eruptions
in the early 1970s, unfortunately without direct
observations of the impact on the other islands. The
available evidence (observational and stratigraphic).
however. is that Rakata has not been affected by significant
ash fall from the new volcano. The prevailing
winds tend to carry ash clouds away from Rakata and
towards Sertung in the dry season and towards R. Kecil
in the wet season (Dammerman 1948).
Gas damage. -Gases produced by Anak Krakatau
ma?/ have significantly influenced the vegetation of Sertung
in 1930 (Docters van Leeuwen 1936). and of both
66 R. J. WHITT'AKER ET AL. Ecolog~calMonographs
Sertung and R. Kecil in 1952-1 953 (Borssum Waalkes
1954, 1960), but Dammerman (1948) argued that the
damage of the 1930s might have been the direct product
of ash-fall (and rain-wash).
Earthquakes.-Landslides, and in particular, rockfall
down the north face of Rakata. have often been
associated with earth tremors centered within the group.
Several such events were witnessed in the early years
of Anak Krakatau's activity (Stehn 1929. Docters van
Leeuwen 1936) and were also observed in 1984.
HUMANINFLUENCE
One of the most significant features of Krakatau in
the present context is how little the islands have been
affected by human disturbance. During the period 1916-
1922,Rakata was inhabited by a small group employed
by a Mr. Hand1 in pumice extraction. A garden was
planted around their cottage on the southeast side. and
several weed species were introduced en route from
the landing stage. Most were lost soon after the concession
was abandoned (below). and none has had a significant
role in the vegetation communities of Rakata.
In 1919, visiting scientists accidentally started a fire
that burned a sizeable part of the west side of the island
(Fig. 3). The vegetation of the area consisted predominantly
of grass-steppe, which at the end of the dry
monsoon formed a highly flammable mass. It was principally
this material that burned, rather than the woody
parts of trees and shrubs. According to Docters van
Leeuwen (1936:193),"After but a few years not a single
trace of the fire was discernable. . . ." That is not to
say. however, that it had no medium-term effect on
the vegetation composition (and successional direction)
of the affected area. For example. Ficus spp. and
.%facarangatanarius apparently survived the fire better
than other tree species (Docters van Leeuwen 1936:
134).Nonetheless. it was his view that neither the fire
nor the inhabitants had more than a temporary effect
on vegetation development. Small-scale interference
has continued on the island, although without the establishment
of dwellings. In the early 1950s, a limited
amount of shifting cultivation was reported, including
an area of 500 x 50 m on the southeast side. which
had been cleared for growing coconuts (Hoogenverf
1953, Borssum Waalkes 1960).
Ernst (1908) speculated that a party of surveyors
might have been responsible for planting coconut away
from the beach on Sertung and for introducing Carica
papaya. In 1951,a small garden was found on Sertung,
but both the garden and an accompanying dwelling
were destroyed in the 1952eruptions of Anak Krakatau
(Borssum Waalkes 1960). Between August 1896 and
January 1897, a small topographical survey team was
stationed on R. Kecil. and in the period 1928 to 1931,
the Volcanological Service had an official observation
post there (Dammerman 1948).A few weeds were found
along the paths of the latter (Docters van Leeuwen
1936).but apparently none has survived. The Japanese
V O ~ .59. No. 2
are reported to have had an observation post on R.
Kecil in the early 1940s (undocumented) and pumice
extraction is also reported from the island in 1951
(Borssum Waalkes 1960).
Although the islands have a protected status (Genolaganni
1985), it is probable that intermittent smallscale
interference continues at and near the coast at
convenient landing points. These events constitute only
short-term, localized disruptions to the vegetation. One
way in which people may have provided a significant
influence on plant community dynamics is by introducing
certain animals. e.g.. Rattus spp. to each island
(Dammerman 1948)and possibly pigs to R. Kecil (Bush
et al. 1986b),but their impact on the vegetation succession,
if any. remains unknown.
Very little is known concerning the 1680-1 883 Krakatau
flora. Docters van Leeuwen (1936) listed six species
known from the coastal vegetation. These were Intsia
amboinensis, Mucuna gigantea (Leguminosae), Dendropthoe
pentandra Miq.. Viscum articulatum Burm.
(Lorantheaceae), Dysoxylum arborescens (Meliaceae)
and Dendrobium uncatum Lindl. (Orchidaceae). In addition,carbonized
remains of Macaranga tanarius(Baas
1982) have been identified from this period (Switsur
1982). Of these species. both Leguminosae plus D. arborescens
and M. tanarius have all been found on the
group since 1883.
HISTORYOF VEGETATION ONSUCCESS~ON
RAKATA,SERTUNG, 1883 TO 1953AND R. GCIL,
Rakata
The first explorations of Rakata took place in October
1883(when the summit was reached) and in May
1884. No plant life was detected on either occasion.
By September 1884 a few sporadic blades of grass had
appeared (Verbeek 1885). and in 1886 the pioneers of
the new vegetation could be seen from the coast to the
summit (Treub 1888),although the upper reaches were
only examined through binoculars (Docters van Leeuwen
1936). Among the colonists were six species of
blue-green algae, forming a gelatinous layer. suggested
to have been important in improving conditions for
the establishment of ferns which, at this early stage,
almost exclusively covered the interior. Only a very
few angiosperms were observed. most of which were
restricted to the beach.
By 1897 the interior of Rakata was clothed in a dense
savanna-type grassland, dominated by Saccharum
spontaneum and Imperata c).lindrica,interspersed with
small clusters oftrees. Ferns dominated only the higher
regions and the balance of species had also greatly shifted
in favor of the flowering plants. On the beaches a
Pes-caprae formation (a typical tropical formation
named after the creeper Ipomoea pes-caprae) was already
prevalent. backed in many places by the first
June 1989 RECOLONIZATION AND S1JCCESSION ON KRAKATAU 67
signsof the coastal Terrninalia/Barringtoniaand Casuarina
communities. By 1906, the vegetation had become
further enriched (99 species of angiosperms) and
the coastal vegetation had developed into discontinuous
young woodland. incorporating a large proportion
of Casuarina equisetifolia, with scattered Barrlngtonia
asiatlca, Terminalia catappa, Calophyllurn inophj,ll
u ~ n ,and Hibiscus tiliaceus (Ernst 1908). During this
period there developed among the lowland grasslands.
patches of woodland containing Ficus spp.,A14acaranga
tanarius, and other secondary forest species (Backer
1909).The shrub Cj,rtandrasulcata was common within
a particularly luxuriant patch of woodland. in a ravine
between 300 and 400 m altitude. Above 400 m,
the fern communities were slowly receding upwards
and also contained a scattering of trees (Docters van
Leeuwen 1936).
Over the period 1919 to 1934,a gradual change took
place from savanna grassland and Casuarina equzsetlfolia
woodland to a species-poorbut mixed secondary
forest. Since C. equisetzfolia cannot regenerate under a
closed canopy, the woodlands of the lowland regions
rapidly developed into a mixed .Macaranga-Ficus (especially
F. fulva) forest. with. for example, Prpturus
argenteus. Altitudinal differentiation was noted at an
early stage of forest development. in 1921, when Villebrunea
rubescens and ~Veonaucleacalycina were found
only above 300 m (Docters van Leeuwen 1921. 1936).
Both are common in the upland forests of Java. Above
this altitude. the trees remained rather more scattered.
while Ck,rtandrasz~lcataformed a thick, almost monospecific
scrub from -360 m to the summit. The young
trees observed among the C. sulcata included many
bird- and bat-dispersed Ficus spp., commonly F. ribes,
F. lepicarpa, and some already huge specimens of F.
pubrnervis. At this stage. the forest was still very poor
in tree species: only 47 had been found, 20 of which
were members of the coastal flora (Docters van Leeuwen
1923).While the composition of the coastal communities
remained little changed throughout. the fern
and grass savanna communities continued to decline
throughout the 1920s and early 1930s,remaining only
in small patches in the lowlands. on some upland ridges,
and on the summit. By 1929 the region from 400 m
altitude up to within 60 m of the summit (previously
Cyrtandra scrub), had become forest consisting mainly
of ,Veonauclea calycina. These developments were accompanied
not only by the decline, and in some cases
the loss of pioneer species, but also by the provision
of new habitats and by a peak in species immigration
(below, Whittaker and Flenley 1982). The epiphytic
vegetation was greatly enriched from that previously
described. and lianes, orchids. forest ferns. mosses. liverworts
and lichens. all increased in number of species
throughout this formative phase of forest development
(Docters van Leeuwen 1923,1929.1936, Boedijn 1940).
By 1951,h'eonauclea calyczna had become the princlpal
canopy tree from near the coast up to just below
the summit (Borssum Waalkes 1960). This is an interesting
development. in that all other marked changes
in community type involving an altitudinal progression
have been of lowland forms spreading up the island.
Neonauclea ca/j,cinamostly occurs in secondary
forest. When full grown it reaches a height of 20 m,
with a girth of 2 m and a rather dense crown (Borssum
Waalkes 1960). The relatively sparse undergrowth of
this forest was characterized by the shrubs Leea sambtlcina
(in ravines) and Leucosjlke capitellata (on ridges),
with Nephrolepis biserrata also very common in the
ground flora at lower altitudes. The 1951 Areonauclea
forest displayed a gradation with altitude, similar to
that emerging in the 1920s and 1930s. In coastal localities
and up to 50 m altitude. Terminalia catappa,
Ficus.fulva, F. ,fistulosa, F. hispida, Macaranga tanarius,
Tarenna fiagrans, and Melochia umbellata were
found. From 50 to 200 m, N. calycina was practically
the only species in the tree layer. Other species of the
zone included Tectaria polymorpha, Ficus ampelas, F.
annulata and Villebrunea rubescens. Between 200 and
500 m, the forest included Ficus ~lariegata,F. retusa,
F. gibbosa, F. querczfolia, F. pubinervis, and Parinarium
corymbosum. The ground flora (e.g., Selaginella
plana) and the cover of epiphytic mosses and ferns
(e.g., Antrophjwn reticulatum, Crepidomanes bipunctatum)
were also much denser than in preceding zones.
The forest above -500 m was characterized by a thick
moss layer, much stouter trees. and ferns such as '4splenium
nidus, lending it the appearance of a montane
rain forest.
The summit vegetation consisted of a dense shrub
layer. scattered trees and some dense patches of Saccharzlm
spontaneurn. The early dominant shrub Cyrtundra
sulcata had declined in importance. while SchefJera
polj,botrya, a species not previously recorded on
the island, was found to have replaced it at the highest
altitudes. Other species of this zone included Leucosjke
capitellata, Neonauclea calycina, Macaranga tanarius,
Piper blumei, Blurnea riparia,Aeschynanthus ~,olubilis,
and Medinilia speciosa. The moss flora was very rich.
covering ground and higher plants alike.
Sertung
The first description of the vegetation of Sertung was
provided by Penzig (l902), who landed briefly in 1897.
He found a small woodland of 5-6 m high Caszlarina
equisetlfolia on the south point of the island. There was
a beach vegetation of Pes-caprae, and some of the constituents
of the present Terminalia forest, e.g.. Termrnalia
catappa and Pandanus tectorius. Although unable
to explore the interior, Penzig described the
vegetation as consisting of closed stands of grasses. as
found on Rakata. In 1906,patches of Casuarina equisetzfolia
were found on the east coast. between which
were groups of trees and shrubs typical of the later
Terrninalia forest (Ernst 1908). Most of the interior
was covered by savanna grassland similar to that of
68 R. J. WHITT'AKER ET AL. Ecolog~calMonographs
vol 59. No.2
Rakata. and containing ferns. Compositae. terrestrial tervals between the events. It should be emphasized
orchids. and some scattered shrubs and trees, such as that the map reproduced in Fig. 3 was drawn in relation
Ficus,fi~lva,F. septica, F. hirta, and .Melastoma aflne. to the 1930 eruption, and that no such data exist with
By 1919 the hills of Sertung had become entirely regard to these later and possibly more serious erupcovered
by grass-steppe. within which were scattered tions.
trees. In the ravines, .Macaranga tanarlus-F~cus~ful~~a The next documented visit by a botanist was not
forest was already the dominant cover type. The coastal
Pes-caprae and 7erminalia communities were well developed.
especially on the level northern part of the
island. Sertung lacked the upland communities of Rakata,
but held a small area of mangrove in a lagoon. a
habitat absent from Rakata. Apart from these habitatbased
differences. vegetation succession continued to
follow a similar course on both islands during the rest
of the 1920s.
During the period 16 July to 7 August 1930, Sertung
was affected by directional eruptions from Anak Krakatau
(Fig. 3). The depth of ash deposited was not great
in comparison with the 1883 covering (Docters van
Leeuwen 1936). and the full impact of the eruptions
was not immediately obvious. By March 1931,half the
trees had died in some areas, and the most disturbed
parts resembled "a European wood in winter." Much
of the damage was suggested to have been caused by
poisonous gases or some sort of acidic washout. At
earlier stages of the emergence of Anak Krakatau, the
northern coastal forest of Sertung was damaged by high
waves associated with the eruptions of 1928 (Stehn
1929).
By 1931. a mixed forest, densely festooned with
climbers, had replaced the earlier Casuarina woodland
on the northern part of the island. In the northeast
there were large marshy patches covered with Ischaemum
muticum and Hibiscus tiliaceus, while the main
saltwater lake still contained a small area of mangrove.
Inland the damage was found to be greater (Fig. 3).
The ravines were the most disrupted areas, a pattern
attributed to landslides associated with earth-tremors
and to windthrow (Stehn 1929. Docters van Leeuwen
1936). Some of the standing trees had begun to sprout
again. and numerous seedlings had responded to the
break in the canopy. High Saccharum covered much
of the ground surface. probably largely from rhizomes
that had persisted through the preceding period of shade.
Those areas in the hills that had not been badly affected
were almost completely covered with a Macaranga
tanarius-Ficus fulva woodland, with only patches of
grasses and ferns.
Subsequent eruptions in the 1930s also hit Sertung.
although these events were not well documented. For
example, in 1934. a visitor described the island as having
a "wintry" aspect. Further damage occurred in 1935.
and Stehn wrote that Sertung ". . . looked grey and
disconsolate. Heaw showers of ash and sand have swept
across it . . ." (reported in Docters van Leeuwen 1936).
The damage was unlikely to be comparable with the
devastation of 1883. but the effect on the vegetation
was likely to have been compounded by the short inmade
until 1951 when Borssum Waalkes (1960) spent
2 h collecting on the island. There followed a period
of volcanic activity which culminated on 10-1 1 October
1952 with extensive damage to the forests ofboth
Sertung and R. Kecil (Fig. 6). Estimates of the depth
of ash-fall on Sertung vary from 0.5 m (Borssum
Waalkes 1954, 1960). to a range of from 0.5 to > 1.5 m
by De Neve (1953a, b, personalcommunication 1984).
De Neve reported an almost complete destruction of
the foliage, while Borssum Waalkes described the island
as looking as if a big fire had ravaged it, with only
the trunks and the thickest branches of the trees remaining.
This initial impression of devastation was
moderated by a closer examination. Casuarina forest
on the spit was found to be damaged. but apparently
as a consequence of storm or wave action, rather than
ofash-fall. On moving southwest along the beach. however,
the physical damage to the vegetation was seen
to have been tremendous. trees having been "broken
like matchsticks." Most also looked scorched (Borssum
Waalkes 1954).The coastal vegetation had been largely
defoliated, but already many shrubs and small trees
were sprouting from axillary buds. In addition. two
species of the Pes-caprae formation (Ischaemum muricum
and Cana~~aliamaritima) had already reached
the surface again. having grown through 15 cm of ash.
The inland forest was also badly damaged. although
the higher parts appeared to be becoming green again
in places. Despite the extent of the damage. Borssum
Waalkes (1960) concluded that the vegetation cover
would have "recovered" within a couple of years. providing
no other violent eruptions took place. That view
does not. however, preclude the possibility of effects
on the direction or rate of compositional changes. In
fact. further disturbance did occur in September 1953
(Fig. 3 and De Neve 1953a,b, personalcommunicarion
1984). and has occurred subsequently, unfortunately
without close documentation as to the ecological im-
pact.
Rakata Kecil
In 1896-1897, a dense vegetation cover was described
from the beach and parts of the interior of R.
Kecil (Penzig 1902). A few groves of Casuarrna equisetzfolia
were noted near the beach along with species of
the Pes-caprae formation. The communities described
were comparable with Rakata. although ferns appeared
less important. Ernst (1908) noted that R. Kecil. with
its steep coast, was almost without strand vegetation
in 1906.Trees and shrubs were sparsely scattered among
the grass savanna of the interior, but the vegetation
appeared less advanced than on either of the other
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 69
islands. Backer (1909) collected from the beach flora
in 1908, but no further details are available of the
vegetation succession until Docters van Leeuwen's
(1936) studies of 1928-1 932. Pes-caprae and Termirialla
woodland were well developed by 1928,but were
restricted to the small areas of gently shelving beach.
Mixed forest had developed in near-coastal areas. but
the hills were mostly covered by grass-steppe, dominated
by Saccharum spontaneum with Imperata cylind
r i c ~ .Scattered trees, mainly Macaranga tar~ariusand
Ficusfulva, were widespread within the grassland and
provided the dominant community type in the ravines.
Once underway, this stage of the succession proceeded
very rapidly. and by 1932 the grass-steppe had mostly
disappeared. except from a few ridges and recent landslide
scars. As on Sertung. the inland forest remained
poorer in species than the mixed near-coastal forest.
Tinloriius con~pressicaz~liswas already common in the
inland forest of R. Kecil. while the grasses had been
replaced in the undergrowth by ,Vephrolepis sp.
After the 1952 eruption, Borssum Waalkes (1954,
1960) described damage similar to that observed on
Sertung, although he did not actually land on R. Kecil.
De Neve @ersonalcotnnzunication) recorded that 0.7
m of fresh ash had fallen on the northern end of the
island and that 90°/o of the vegetation of the island
appeared scorched. Approaching the island from the
west in November, Borssum Waalkes observed that
some greenery was visible near the coast and to the
south. Rounding the southern tip of the island, the east
side (farthest from Anak Krakatau) was found to be
much less damaged. Some trees (mainly in coastal areas)
appeared completely unharmed. Eruptive activity affected
R. Kecil again in 1953. although the damage
appeared to be restricted to the southern part of the
island (De Neve 1953a, b, personal comtnunication
1984).
Succession 1883-1 953 on Rakata, 

Sertung and Rakata Kecil: concluding remarks 

Until 1928, each island experienced similar vegetation
successions, with the exceptions of the differing
proportions of particular habitats noted. In particular,
Sertung and R. Kecil are considerably lower than Rakata,
and this may be one of the reasons that the 1920s
lVeonauclea forests of Rakata, which developed first in
the uplands. were absent from the other islands. During
the 1920s. many species that were bird or bat dispersed
(e.g.,ilrdisla hurnilis. Cjrlea barbata, D~.so.xylutngaudichaudianunz,
and .Melra azedarach) arrived on the
group. as the habitat for these fauna became more suitable,
constituting a mutually reinforcing effect (Hoogerwerf
1953). Docters van Leeuwen (1936) suggested
that some differences between the three islands may
have been related to the time of arrival of particular
species to each island. In particular, Tinzonius conzpressicaulis
was abundant in the interior of R. Kecil,
but unimportant on the other islands. Thus, chance or
uneven distribution of favored points of landfall for
the avifauna may have been leading to some interisland
differences. Variations in the rate of successional
development were also evident. In particular, the vegetation
of west and northeast Rakata, and of R. Kecil
and Sertung. appears to have been discernibly slower
to develop towards forest than in south and south-east
Rakata (Docters van Leeuwen 1936:166). Moreover.
by 1931, the destruction wrought on Sertung had, at
least temporarily. introduced greater variation. Subsequent
eruptive episodes, for example in 1952-1953.
were known to have hit both Sertung and R. Kecil.
These eruptive influences have almost certainly had a
significant impact on the course of succession.
F ~ e l dmethods
The major vegetation surveys in this period were in
1979 and 1983 by the Hull University expeditions
(Flenley and Richards 1982, Bush et al. 1986a) and in
1982 by the Kagoshima University expeditions (Tagawa
1984). The vegetation analyses reported are based
on the work of the Hull expeditions and additional
observations by Bush in 1984,although all survey data
are incorporated in the floral analyses.
The expeditions of 1979, 1983, and 1984 enumerated
the vegetation communities of the main islands
by means of quadrats in which tree cover was quantified
and the diversity of the ground flora recorded.
Two factors ultimately restricted plot size: time and
terrain. Species-area curves indicated that plots as small
as 400 m2 provided an adequate local representation
of the vegetation of Rakata (Whittaker 1982). Most
vegetation plots were larger than this. the norm being
900 m2,and the maximum 2500 m'. The sample was
stratified. with the aim of representing the full range
of habitats within the group while minimizing sampling
effort (Fig. 7). Plot locations were chosen on the
criterion of suitable topographic conditions. Girth at
breast height (gbh) was recorded by species, for each
tree that exceeded 30 cm gbh. (Diameter at breast height
can be obtained from girth by dividing by T . ) In all.
67 species were recorded on this basis. from 19 plots
on Rakata, 13 on Sertung, and 5 on R. Kecil (see Fig.
7 legend for plot sizes). Within each plot the composition
and relative abundance of the ground flora, epiphytes,
and climbers were also recorded. On Anak
Krakatau, where the stands of consistent physiognomic
type were small, and generally aligned parallel to the
coast, the quadrat sizes were also smaller (250 m').
Percentage cover estimates were made for all species
of higher plants (reported in Bush et al. 1986~).
General plant collecting was carried out by each expedition,
with the aim of making as complete a survey
of each island's flora as was practicable, given the difficult
nature of the terrain. These data together with
FIG.7. Location of vegetation plots sampled In 1979, 1983.
and 1984 on Rakata. Sertung and Rakata Kecil. Site altitudes
(in metres) and areas (in square metres) are as follows: Rakata
(1)10, 2500: (2)l 10. 1250: (3)260, 400: (4)420, 1250; (5):1
(i.e.. beach-edge), 1250: (6)l. 1800: (7)1, 625: (8)670, 400:
(9)l. 900: (10)40. 625; (11)15. 500: (12)150, 1600; (13)170,
400: (14)85. 625: (15)250. 1000; (16)400, 750: (17)530, 625;
(18)730. 400: (19)500. 625: Sertung (1)5. 2500: (2)70, 400;
(3)5. 540; (4)35. 500: (5)3. 500: (6)45. 400; (7)70, 600: (8)70,
450: (9)lOO. 900; (10)35, 900; (1 1)80. 900: (12)170, 900:
(13)160. 900. R. Kecil (l)90. 900: (2)115, 750: (3)135, 1050:
(4)125. 900: (5)90. 900.
SERTUNG
RAKATA KEClL
0 1 km
LJ
the revised plant lists for all earlier surveys are recorded
in Appendix 1 (Rakata. Sertung, and R. Kecil) and
Appendix I1 (Anak Krakatau). Provisional identifications
were made at the Herbarium Bogoriense. Duplicate
specimens were sent to the Rijksherbarium, Leiden,
and to Hull University (1979, 1983, and 1984
collections). and Kagoshima University (1982 collec-
tion).
VEGETATION PLOTS
1979
1983
1984
,Vunzerical analysis of the vegetation data
-
RAKATA
N
7.
0 1 km
1
The tree girth data recorded in 1979, 1983. and 1984
were converted to cross-sectional area (i.e., basal area
or "ban) and standardized by site (Jones 1986a).Analysis
was performed by means of Detrended Corre'AKER
ET AL. Ecolog~calMonographs
Vol. 59. No. 2
spondence Analysis (DCA; Hill 1979a),and Two-Way
Indicator Species Analysis (TWINSPAN; Hill 1979h;
see Fig. 8). Additional information on the composition
of a selection of the sites is provided in Fig. 9. DCA
is an eigenvector ordination analysis that produces results
similar to principal components analysis. but
which is more effective at displaying strong floristic
gradients (Hill and Gauch 1980, Gauch 1982).
TWINSPAN is a polythetic. divisive classification
technique (Hill 1979b).This form of classification uses
a maximum of information and provides a hierarchy,
i.e., relationships between groups are discerned (Gauch
1982). The technique operates on a semi-quantitative
level, employing "pseudospecies cut-levels," which divide
species into crude abundance scales. The optimal
cut-levels and weightings are determined empirically
and, in this case. the most intelligible results were obtained
with pseudospecies cut-levels of 0, 2, 5. 10. 20.
40, and 70% ba and weightings of 1, 1. 1, 2, 2. 3, 4,
respectively (Bush and Whittaker 1986). In practical
terms this means that, for example. twice as much
weight is attached to values of 10-39% ba than to
values of <9.9% ba. Given the range of values in the
data. these appeared to be sensible levels. utilizing a
maximum of the information present in the data and
attaching greater importance to the forest dominants
than to the rare occurrences or understory species. The
stoppingrule used was that groups of less than five sites
should not be subdivided any further. The pseudospecies
preferentials at levels 6 and 7 (Hill 1979b)were
utilized to annotate the hierarchy. Essentially they indicate
species that accounted for ba in excess of 40%.
and which were preferential to the sites on one side of
a division. They thus provide an objective label for the
forest types separated at each division. For further explanation
of this technique. see Gauch (1982).
DESCRIPTIONOF THE VEGETATION
COMMUNITIESOF 1979-1 984
Zrztmductiorz: The T 61'Z1YSPP31\.'
class~jicationand DC.4 ordinationa
,framert.ork .for description
Hierarchical classification by TWINSPAN was utilized
to provide an objective framework for the full
description of the current vegetation communities of
the three main islands (Fig. 8A). The first level of the
classification distinguished between the .Veonauclea
calycina-Ficus pubinervis forests of inland Rakata and
the forests of R. Kecil, Sertung, and coastal Rakata
(Ti~noniusconzpressicaulis present). Subsequent levels
on the right of the analysis separated the inland forests
of Rakata in a pattern generally related to the distributions
of lVeonauclea calycina and various Ficus spp.
On the left side of the hierarchy. the second level of
the analysis divided five of the seven coastal/nearcoastal
Rakata plots (Ter~ninaliacatappa. Casuarina
equiset~folia,and Barringtonia asiatica-rich) from the
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 71
Rak Rakata
Kec R Kec~l
Ser Sertung
Ba Barr~ngtoniaasiatica Fa FICUSampelas Nc Neonauclea calyc~na
Ce Casuarina equisetfolia Fp FICUSpubinervs Te Term~naliacatappa
Dg Dysoxylum gaudichaudianum Fr Ficus ribes Ti Timon~uscompressicaulis
Ft Ficus tinctorla
Kec 2,3 I I
Rak 2-4 10,13 Rak 16.17
Ba
00 Te
A RAKATA
L R KEClL
SERTUNG
Upland Rakata
FP
TI 01 10 Nc
FIG.8. (A) TWINSPAN classification of the vegetation plots sampled in 1979-1984 on Rakata. Sertung, and R. Kecil.
Basal area data standardized by site. of the arboreal component of >30 cm gbh. The hierarchy has been annotated with the
strongest preferentials (6th and/or 7th cut-levels occurring on only one side of a division). Cut-levels 0. 2, 5. 10, 20. 40, and
70%. weightings 1, 1. 1. 2. 2. 3, and 4. After Bush and Whittaker 1986. (B) DCA axes 1 and 2 of the vegetation plots sampled
In 1979-1984 on Rakata. Sertung. and R. Kecil, annotated with the TWINSPAN groupings from Fig. 5A (solid lines). Axis
units are average standard deviations of species turnover (Hill 1979~).
11
Ce
000 Ba
generally Timonius compressicaulis-rich Sertung and /urn gaudichaudianurn-rich forest types (Sertung and
R. Kecil plots and the two remaining near-coastal Ra- R. Kecil).
kata plots. Within the latter group, further divisions One of the features of Detrended Correspondence
appeared to distinguish between lVeonauclea calj.cina Analysis (DCA) is that the ordination axes are scaled
(Rakata), T. catappa, T. cornpressicaulis, and Dj3soxj.- consistently (Hill 1979~);thus the axis units can be
Nc 101001 010 Nc
0100 Te
Ti 011 100 Fp
N c 0101 0110 TI
Rak 5.6. Rak 1
7.9
Dg 0111
Rak 14,l5,19
Fa
10100 Nc
1010 Nc
Ft 10101
Ser 1.2.3.4. Ser 10 Ser 6,8.9. Kec 1.4.5
Rak 11.12 11-13
Rak 18
Fr 1011
Rak 8
R. J. WHITTAKER ET AL. Ecolog~calMonographs
Vol. 59. No. 2
I
0
i49 50-99 S 100 i49 50-99 5100
GlRTH AT BREAST HEIGHT (cm) GlRTH AT BREAST HEIGHT (cm)
L,
i49 50-99 5 100 i49 50-99 3100
GlRTH AT BREAST HEIGHT (cmi GlRTH AT BREAST HEIGHT Icm)
Io01KECS
2 0 1 F ~ a F p ivrM~ Va N~ Va Nc
0
i49 50-99 3100 2 49 50-99 i100
GlRTH AT BREAST HEIGHT (cm) GlRTH AT BREAST HEIGHT lcmi
i49 50-99 3100 2 49 50-99 % I 0 0
GIRTH AT BREAST HEIGHT (cmi GIRTH AT BREAST HEIGHT (cm)
FIG.9. Tree-size histograms for a selection of the vegetation plots sampled on Rakata. Sertung, and R. Kecil in 1979-
1984. Species codes: Ce = Chsuarlna cquisetlfolia; Dg = Dysosylurn gaudrchaudianuln; F = Ficus sp.; Fa = Ficus ampelas;
Ff = F~cusfulca; Fi rihes; Fp puhinercis; Fr = Ficus retusa: Fs = Ficus septica: Fv = Flcus variegata: Ht == FICLLS = F ~ u s
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 73
TABLE1. Range of SD scores on DCA site axes, occupied by Rakata, Sertung and R. Kecil plots.* The values are standard
deviations of species turnover at the individual sites (Hill 1979a), and provide an indication of the vanability accounted
for by the vegetation sampled on each island.
Axis 1 Axis 2 Axis 3 Axis 4
Island n Range Span Range Span Range Span Range Span
Rakatat
Coastal 5 0.0-1.7 1.72 1.2-1.8 0.64 0.0-1.6 1.55 0.0-1.1 1.12
Inland 14 2.7-6.0 3.33 0.0-4.5 4.49 0.9-1.8 0.99 0.3-2.2 1.89
All 19 0.0-6.0 6.04 0.0-4.5 4.49 0.0-1.8 1.84 0.0-2.2 2.15
Sertung 11 1.3-2.5 1.20 1.4-2.7 1.34 0.0-1.5 1.54 0.7-2.3 1.53
R. Kecil 5 1.5-2.6 1.12 1.8-2.1 0.34 1.5-2.7 1.20 0.8-1.2 0.40
S and K$ 16 1.3-2.6 1.37 1.4-2.7 1.34 0.0-2.7 2.69 0.7-2.3 1.53
All sites 35 6.04 4.49 2.70 2.26
n = number of sites in each group. 

t The location split for Rakata is sites 1, 5. 6, 7, 9 = coastal, sites 2-4. 8. 10-19 = inland. 

$ S and K = Sertung and R. Kecil combined. 

* The eigenvalues for axes 1 to 4 are 0.832, 0.490, 0.313, 0.189, respectively. Axes 1 and 2 are displayed in Fig. 8B.
used as a measure of the amount of variation in vegetational
composition accounted for by the sites from
each island within each axis. The DCA ordination produced
a first axis similar to the overall layout of plots
in the TWINSPAN analysis (Fig. SB), with Rakata
coastal and inland plots occupying the extremes of the
axis. a span of 6.04 SD units in total (Table 1). The
second axis split the inland Rakata forest group into
upland stands at the positive extreme of the axis and
lowland stands at the negative extreme. Neither axis
accomplished any significant separation of the forests
of Sertung and R. Kecil. leaving them as a compact.
centrally located group. The third axis did not provide
an unequivocal pattern. perhaps due to the fairly large
proportion of zero entries in the data matrix, but at its
extremes did appear to separate D ~ ~ s o x ~ ~ l u mgaudichaudianum-rich
stands (Kec 1. 4, 5) from Terminalia
catappa-rich stands (e.g.. Rak 7. 9, and Ser 2. 4). Only
on this axis do the Sertung and R. Kecil stands combined
provide as much variation as the inland plots of
Rakata, and even in this axis the five coastal Rakata
plots contain greater variation than those of each when
taken separately (Table 1). The fourth axis was not
interpretable ecologically. These analyses clearly show
that of the forests sampled from the three islands, by
far the most varied were the Rakata stands, with Sertung
intermediate and R. Kecil the least varied.
Rakata
The first level of the TWINSPAN analysis and the
first axis of the DCA separated the coastal and nearcoastal
sites of Rakata from the inland forests (Fig. 8).
Coastal vegetation communities.-Eroding coastlines
along much of the Krakatau islands offer poor
habitats for plant colonization. Trunks fallen from the
cliff above often litter the intertidal zone, e.g.. on the
southern shores of Rakata. The forest at the cliff edge
may contain one or two light-demanding shrub and
herb species (e.g., Lantana camara and Ezlpatorizlin
odoratum). but often it is essentially a low-altitude secondary
forest community that has been exposed by the
cliff retreat (Bush 1 9 8 6 ~ ) .
In less extreme beach environments, coastal trees
and shrubs, e.g.. Morinda citrjfolia, Pandanus tectorius,
and Premna corj~mbosa,may establish on the cliff-top
and even at the base of the cliff. These individuals
seldom reach maturity before they are uprooted by
further erosive action. The canopy ofthe lowland forest
is broken at the cliff-edge. allowing the inland migration
of the coastal fringe community. The latter remains
a narrow belt as the outer edge is continually
pared by the action of the sea. Rakata also has areas
of gently shelving sandy beaches supporting Pes-caprae
backed by stands of Barringtonia asiatica and other
species of the coastal woodland fringe (Fig. 10).
1. Pes-caprae.formation. -Pes-caprae formations are
recorded from low-energy beach environments
throughout the Indo-Pacific (Whitmore 1984). This
formation of low-growing herbs and creepers commonly
includes Ipomoea pes-caprae. Canavalia maritima,
Vigna marina. Spin~fexlittoreus, and U'edelia
b~flora.Coastal erosion ensures the expanse of Pescaprae
on Rakata has never been great at any stage
after 1883. Being a formation of herbs and creepers. it
is not represented in the TWINSPAN analysis.
2. Terminalia.forest lBarringtoniaformation). -The
large fruits produced by Barringtonia asiatica are exclusively
sea-dispersed (Docters van Leeuwen 1936);
thus. unlike many other constituents of the coastal
vegetation. B. asiatica is restricted to coastal sites. AlHihiscus
tilraceus: Mc = \lorinda ci~rifolia:Mt = .\rlacaranga tanarius; Nc = ,Veonauclea ca!,:cina; Pa = Pipturus argenteus:
Rg = Raderrnachera glandulosa: Tc = Terrninalia catappa: Ti TI= Timonius cornpre.~s~caulis: = Tetrastlgrna lanceolarlurn:
Va = I2rnonia arhorea: Vr = I'~1lehrunearuhescens; X = Unknown.
74 R. J. WHITTAKER ET AL.
RAKATA 

KEClL 

ANAK
KRAKATAU
0 3 km
I 1
Ecological Monographs
Val. 59. No. 2
Barringroniar
rlch coastal
1Terniinalia LJ
rlch coastal
Casuarina
-
Dysoxyluni
[IIIIIl Neonauclea
Neonauclea~Ficus~
Ficus especlaly
F pubinervis
Schefflera scrub
Unknown on Rakata
A Hlghest polnt
above c 550 m forest
~ncreas~ngly'mossy
FIG. 10. Principal vegetation types of the Krakatau Islands. Generalized map derived from field survey between 1979
and 1984. Large areas of the islands were covered by communities dominated by single species. e.g.. the lowland ,Veonauclea
forest of southeast Rakata, and extensive areas of early regrowth T~moniusforest on Sertung and R. Kecil. In parts, however,
the canopy composition was less monotonous. Mostly transitions were not sharp edged. but rather gradations between forest
types (e.g.,between Timonius and Terminalla forests on much of Sertung). Exceptions appeared to relate to sharp boundaries
in topography, or to recent environmental disturbances.
though "Barringtonia formation" is the classical name
for the coastal communities. it is often not the dominant
canopy tree. On Krakatau, as shown by the
TWINSPAN results (Fig. 8), the canopy is dominated
principally by Terrninalia catappa. It is therefore fitting
to call these communities "Terminalia forests" (cf. Tagawa
et al. 1985).
Terminalia catappa is a common component of the
Indo-Pacific strand flora (Whitmore 1984) but. although
primarily sea-dispersed, the fruits may be spread
locally by rats. Dispersal by rats probably explains this
species' presence some 450 m inland at an altitude of
40 m (in Rak 10: Fig. 7). The seaward margin of Terrninalia
forest was often composed of a fringe of the
thick, irregular trunks of Barringtonia asiatica that had
been undercut by the sea (e.g., in Rak 5 and 7). Shrubs
and small trees growing in this fringing forest included
Hibiscus tiliaceus, Pandanus tectorius, and Morinda
citrlfolia, but immediately inland of this fringe Terrninalia
catappa was the dominant species. The canopy
of these forests was formed by understory trees 9-1 1
m in height with the larger emergent species. e.g., T.
catappa and Ervfhrina orientalis, rising to 13-15 m.
On moving away from the fringe, there was a change
in the understory species. as predominantly coastal
species were joined by species such as Ficus.fulva, F.
septica, and Macaranga tanarius. Other characteristic
species were Hernandia peltata, Calophyllum inophyllum,
Desmodiurn umbellatum, and, in the case of Rak
6. a stand of Casuarina equisetifolia, a remnant of the
once abundant coastal distribution described by Docters
van Leeuwen (1936).
In Rak 1 there were 17 species/800 m2 compared
with a maximum of 10 species in an equivalent area
of the other coastal plots (Rak 5, 6, 7, and 9). Many
of the additional species (e.g., Neona~icleacalj~cina)are
characteristic of the inland forest, indicating that this
plot was located in the ecotone between the coastal and
inland forests. This difference in floristic composition
was reflected at the third level of the TWINSPAN analysis,
where Rak 1was separated from the Barringtonia
asiatica- and Casuarina equiset~folia-dominatedcoastal
sites (Fig. 8).
3. Casuarina forest.-Casuarina equisetlfolia is a
characteristic tree of disturbed or unstable habitats,
and a pioneer in coastal habitats. Although once a major
component of the pioneer vegetation on Rakata.
by 1979 it was found to have become restricted to one
June 1989 RECOLONIZATION AND S1JCCESSION ON KRAKATAU 75
or two spots on the south coast (e.g.. Rak 6), and to
the precipitous north face of the island, where a normal
forest cover could not establish.
Inland.forests.-The coastal forest was found to grade
into the inland forests, forming a continuum. This is
exemplified by the positions of Rak 1, 11, and 12 (all
near-coastal) in the DCA and TWINSPAN analyses
(Fig. 8A and B). Rak I I was -50 m inland and Rak
12was located on the promontory above Zwarte Hoek.
Although a high proportion of the basal area (44 and
62% ba. respectively) was attributable to Neonauclea
calycina, the presence of Terrninalia catappa and Tirnonius
cor?zpressicaulisin both sites was sufficient to
place them on the left of the initial division of the
TWINSPAN analysis. The right side of the classification
contained only inland Rakata sites, divided into
four groups. The separation of the two highest plots,
Rak 8 and 18, from each other is viewed as an artefact
of the sampling, as the most abundant arboreal species
in both was Scheflera polybotrya, which had too small
a girth to be represented adequately in the data set.
These two plots were sufficiently similar for us to override
the structure suggested by TWINSPAN and to
treat these stands as belonging to one vegetation type.
The remaining sites did not segregate in a clear altitudinal
pattern but rather their placing was related to
the abundances of N. calycina, Ficus pubinervis, and
F. tinctoria.
1. Neonauclea ,forest.-Areonauclea calvcina was
found to be the dominant canopy tree over most of
the interior of Rakata, from 40 to >550 m elevation
(Fig. 10). Within this altitudinal range there are variations
in the associated species very similar to those
described in 1951-1 952 by Borssum Waalkes (1960).
Thus, Vernonia arborea was found mainly at higher
altitudes. whereas Pipturus argenteus and ,I.facaranga
tanarius were recorded only in the low-altitude plots.
In addition, there are variations within the forest that
may be ascribed to topography: for example, the shrub
Cvrtandra sulcata is particularly common in the ravines
(Tagawa et al. 1984).
Within the plots of the ,Veonauclea forest (Rak 2. 3,
4, 10, and 13). N. calycina varied from 52 to 89% total
ba, with individuals generally in the range 60 to 100
cm gbh (maximum 220 cm) (Bush and Whittaker 1986).
This was a relatively open forest, with the canopy at
1 1-! 5 m and with distinct ground and shrub layers. In
addition some large specimens of other species were
found, e.g.. Ficus spp. and Tirnonius compressicaulis.
The understory of the .Veonauclea forests included Clidernra
hlrta, Leucosvke capltellata, Leea sambuclna,
drdisia humilrs,and .Vacaranga tanarrus The creepers
Smilax zeylanlca and AVussaendafiondosa and ferns
such as Nephrolepis biserrata and Davallia denticulata
were common constituents of the ground flora, and the
forests also included climbers such as Tetrastigma lanccolarium,
Flagellaria indica, and various Asclepiadaceae.
With increasing altitude a gradual increase in
the cover of moisture-loving epiphytes was observed,
especially of bryophytes, although they did not achieve
the dense cover found within the upland Ficus and
Scheflera communities. Forster (1982)reported a similar
altitudinal trend in bryophytes, which he attributed
to the humidity gradient.
2. Neonauclea/Ficus .forest.-The explorations of
1979-1984 revealed some patches within and above
the fleonauclea forest. with a high Ficus spp. content
in the canopy (Fig. 10). Where Areonauclea calycina
(up to 134 cm gbh and 15 m tall) and F. tinctoria (up
to 262 cm gbh and 16 m tall) shared the dominance
of the canopy (Rak 16 and 17;420 and 550 m altitude,
respectively). the forest was generally composed of larger
trees than in the hTeonaucleaforest, with the canopy at
12-1 4 m and emergents attaining heights of up to 18
m. Among the canopy trees was the largest specimen
of Timonius compressicaulis (2.0 m gbh and 13 m tall)
recorded from any site on the islands. In Rak 17, the
canopy was merged with a dense understory so that
there was a tangle of branches from the forest floor to
-10 m. Emergents rose above this layer, e.g., a specimen
of Vernonra arborea of 176 cm gbh and 17 m
height. Understory species included 'Lfedinilla spp..
Leea sambucina in Rak 16, and Abfedinillaspp., Cyrtundra
sulcata, and Schefnera polybotrj~ain Rak 17. In
this latter plot the growth of these shrubs was so dense
that it was necessary to crawl on the forest floor. The
branches of these shrubs carried an epiphytic flora.
poorly developed at Rak 16,but more luxuriant at the
higher Rak 17, and which included .4splenlum nidus,
Dendrobiurn crumenatum, Pyrrosia spp.. and Selaginella
spp. The ground flora contained Srnilax zeylanica,
Costus speciosus. Davallia spp., and flephrolepis
SPP.
3. Ficus.forest.-Rak 14, 15, and 19comprisea group
at the third level of the TWINSPAN analysis, characterized
by low scores for hTeonaucleacalj~cinaand
high scores for Ficuspubinervrs. Rak 14 (70 m altitude)
was particularly interesting. being dominated by a
specimen of F. pubinervis (girth 495 cm, above the
buttress) and an unidentified emergent (girth 300 cm,
height 24 m) (Fig. 9 and 11). Of all the forests on the
islands, this small patch had the openness and size of
trees most closely approaching that of mature lowland
forest. The understory included Villebrunea rubescens,
Pipturus argenteus,Macaranga tanarius,with a ground
flora of Srnilax zej~lanica,Costus speciosus, Lygodium
circinnatum, and Selaginella sp. Rak 15 (400 m altitude)
contained three principal canopy species, F.pubincrvis
(48%). N. calj~cina(35%). and Tirnonius cornpressicau/is
(11%). Both plots Rak 15 and Rak 19 (520
m altitude) were located in areas of deeply dissected
topography, with almost all trees growing on narrow
ridges between steep-sided gullies. The canopy of Rak
19 was dominated by F. pubinervis, which accounted
76 R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59, No. 2
FIG. I I . FICI~.Y forest on Rakata. A very large specimen of F. pplrhirzervrs (495 cm girth) recorded in Rak 14.plthit~crri~
Note pcr5on at loner right for scale (M. Bush 1984).
tor 85% ba. largely due to one very large individual.
Other si~eabletrees included ~I'.culj~cina,I'ernonia
arhorc~u.I'illehrirrzea ruhcscen.~,and other Ficus species
(Fig. 9). The canopy formed at 8 m. with some specimens
reaching 13-1 6 m. Understory and ground flora
included .\Iedir~illa cpec,io.sa, Clwandra siilcuta, C'j~closorils
cf. interriiptiic. 7'ectariu r?zclar~ocaulu,Piper hlii~nci,and
Be~~otliaicoptera.
Thc two highest vegetation plots. Rak 8 and 18 (670
and 730 m altitude) were located in the near permanentl?
wet cloud forest. At these altitudes the covering
of mosses was even more luxuriant than in Rak 17
(580 m). covering virtually all branches. The forest was
low growing. with branching beginning at ground level.
The shrubs Schqffleru polj.horrya and Leucosyke capitc~llatuwere
the most abundant species in this layer.
The dcnse growth ofthe multiple-trunked S.poI~~hotr~.a
diflora (in Rak 18) protruded above this low canopy.
.Vponaucleucul~v.inuwas virtually absent from this forest
(3 and 0% ba. respectively. in Rak 8 and 18) (Bush
and Whittaker 1986). The low canopy produced a
shaded and species-poor ground flora.
4. S~trnnzitvcyetation.-Below the summit region,
Cjsrtandra siilcata remained an important but mainly
underston component of the 1983 forest. Nearer the
sun~mit.Schcfflera po1j~botr:l.uprovided most cover,
with only a broken canopy oftrees above. The summit
ridge was covered by the pioneer grass Succhariirn
cporztuneunz,with Eiipatoriilrn odoratunz and Lantana
canzara. The occurrence of "pioneer" species at the
summit edge may be attributed to frequent disturbance
events such as lightning strikes, rockfalls. and landslips.
characterized both these plots. Although this was by
far the most common arboreal species present in the
plots. the trunk girth seldom exceeded the minimum
s i ~ ecriterion for data collection: consequently this
species was seriously under-represented in the data set.
The two plots are thus viewed as part of the same
\.egetation type. despite being separated within the
TU'INSPAN hierarch! (Fig. 8A).Occasional FICUSrthes
(in Ruk 8). I~ill~~hrunca nu-rilhctcc,ns, and Sazirauia
Serturzg
The vegeta~ionplots recorded from Sertung and R.
Kecil were placed between the extremes of Rakata's
coastal and inland forest types in the TWINSPAN
analysis and by the first two DCA axes (Fig. 8). They
also contained less variation in vegetation composition
,than Rakata's forests (Table 1). The inland forests of
both Sertung and R. Kecil were predominantly made
up of two communities absent from Rakata. dominated
bq Dj~.so.x~hi~ngazidichazidianzi~n(formerly D.
77June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
amooroides)and Timonius compressicaulis (Figs.9 and
10). A third, coastal-edge community. in which Ficzis
ful~,a,F.septica, and Ter~ninaliacarappa were co-dominants.
was also without close parallel on Rakata. The
.Veonaziclea calj'cina- and FICZISpzibinervis-dominated
forests of Rakata were absent from these islands (Tagawa
et al. 1985. Bush and Whittaker 1986).The vegetation
of these elongated. low-lying islands does not
escape the coastal environmental influences to the degree
reached on Rakata. This is reflected in Fig. 8, and
in the occurrence of coastal species. e.g., Calophyllzim
inophyllum, in the interior.
Coastal and near-coasral com~nuniries.-The basic
constituents of the coastal communities of Sertung were
found to be similar to those described from Rakata,
although the importance of particular species differed.
Those Sertung plots placed in the coastal/near-coastal
group at the third level of the TWINSPAN hierarchy
(Fig. 8) were Ser 1. 3, 3. 4. and 10. The foreshore plot.
Ser 5. did not feature in these analyses, as it contained
no trees >30 cm gbh (Bush and Whittaker 1986).
1. Pes-caprae,formarion.-The best example of this
formation was on the eastern, accreting side of the spit.
It differs little from that described above (see also Partomihardjo
1985).with the exception of seedling Casuarlna
equiserlfolia that were encroaching on the upper
portions of the accreting beach. Elsewhere on Sertung,
the lack of suitable beaches explains the absence or
poor development of this vegetation type.
2. Terminalia ,forest.-In 1982-1 984 Barringtonia
aslatica was found on Sertung and R. Kecil only as
isolated specimens in a few very sheltered locations:
for instance. none was found on the spit of Sertung.
These coastlines are dynamic and rapid erosion has
led to the development of a forest type best described
as near-coastal. This forest extends inland, with Tertninalia
catappa widespread and often dominant in the
canopy. Most of the coastal species of Rakata were
observed on Sertung within T. catappa forest. It was
not until the third divisive level that the near-coastal
plots (group 010 in Fig. 8A) were separated from the
"inland" Timonius co~npressicaulisforest sites (e.g..
see Ser 12 in Fig. 9). Terminalla catappa shared the
dominance of near-coastal plots with Ficzis septica, F.
,fulva, and Timonizis co~npressicaulis.In addition. Calophj.llzitn
inophyllutn, Hernandia peltata, Pandanzis
tectorius, H~biscustiliaceus, AMelastotnauffine, and
Leucosykecapitellara were all abundant. Although most
trees in this forest were 30-60 cm gbh. forming a canopy
at 10-12 m. there were some larger individuals.
e.g., specimens of Ficus retusa (202 cm gbh: 19 m tall)
and Dysoxj>lzimgazidichaudianum (194 cm gbh; 18 m
tall) recorded in Ser 1 (Fig. 9 and Bush and Whittaker
1986).The ground layer was composed of .Vephrolepis
t~lserrata,Srenochlaena palusrris, Davallia denriculata,
Tacca leontopetaloides, and Ezipatorium odorarzim.
There were generally few epiphytes, but the canopy of
Ser 4 was festooned with the climber Cayraria trifolia.
At the northern end ofthe island,another near-coasta1
plot. Ser 10 (900 m2 area. Fig. 7). dominated by
Termlnalia catappa and Timonlzis compresslcaulis,
provided a more diverse forest than that encountered
at the southern end. It contained 33 species. compared
with fewer than 20 in each of Ser 3 and 4 (both 900
m2)and Ser 1 (2500 m2). Ser 10 also included some
species common in the north but absent from the south,
e.g., Gnetutn gnemon and Oncosperma tigillarizitn. The
relatively low values for Ficzis-fiilvaand F.seprica from
this plot. and the dominance of T. catappa, were sufficient
for it to be placed with the near-coastal forests
of Rak 11 and 12 within the TWINSPAN hierarchy
(Fig. 8).
3. Casuarina forest. -Casuarina equisetifolia covered
the length of the spit (Fig. 10) in a woodland of
varying density. Where it cast a dense shade. the undergrowth
was very sparse. but where the canopy was
broken. a poor grassland and herb association dominated
bq Ischaemum mzirlczim could be found. The
trees were often festooned by the climber Flagellarla
indica, and on the sheltered eastern side of the spit the
edges of the woodland were bordered by Caesalpinla
bonduc and Pes-caprae. This noticeable tree was elsewhere
found only on a few steep slopes on the eastern
side.
Inland-forests.-Two main types of inland forest were
found on Sertung, dominated respectively by Dj3so\-j>Izim
gazidichaudianum and Timonius co~npressicazil~s
(Fig. 10). This distinction was reflected in the fourth
level of the TWINSPAN analysis. by which R. Kecil
plots 1. 4. 5 (rich in D. gazidichaudianzitn) were separated
from sites rich in T. co~npressicaulis(Fig. 8A).
The D. gazidichaudianzi~nforests of Sertung. as described
by Tagawa et al. (1985) in 1982. were found
at the northern end of the island. In 1983-1984 (to
avoid unnecessary duplication) inland forest plots were
measured only in the south and middle of Sertung.
These were all found subsequently to be of the T. compressicaulis
type (group 0 1 10) so that the Dysoxylu~n
forests of Sertung were not represented in Fig. 8A (group
01 11).
1. Timonius-forest.-Only on R. Kecil and Sertung
does Timonius cotnpressicazilis constitute a community
dominant. TWINSPAN grouped Ser 6. 8. 9. and
11-1 3 as similar T. cotnpressicazilisstands. Almost pure
stands of 1oung, apparently even-aged individuals covered
substantial areas of inland Sertung. and along the
central ridge and eastern flank there were large areas
where it sudden11 gave way to dense stands of the
pioneer grass Saccharzi~nsponraneum, e.g., in Ser 7
(Fig. 7). Ser 12 (900 m2)is an example of an almost
monotypic stand: of the 120 trees enumerated. 1 12
were Timonius compress~caul~s(Fig. 9). The trees of
this woodland were remarkably uniform in sire. forming
a canopy at 10-1 2 m. The only other canopy species
were Ficus septlca and F.fulita. In the understory were
a variety of shrubs and sapling trees. perhaps the most
'AKER ET AL. Ecological Monographs
important of which were the saplings of Dj.so,~ylu~n
gaudlchaudianzi~n.These were commonly 7 m tall with
a girth of between 17 and 23 cm, and may be expected
to overtop the T. co~npressicauliscanopy. Also present
in the understory were ilrdlsia humilis. Leucosj.ke capltellata.
.2/acaranga tanarius, .2felasiuma affine, and
Piper aduncum. The ground flora was dominated by
Stenoc,hlaena palzistrls and LVephrolepisspp.
At Ser 13. Saccharutn spontaneu~ngrew in dense.
almost impenetrable stands, with individual flower
spikes reaching heights of 3 m. These openings were
fringed by a greater diversity of trees and shrubs than
found in the adjacent forest. Species recorded in these
plots included Ficus.fiilva, F. retusa, F. septica, Leucosj.ke
caplrellata. Morinda cirrlfolia, and lVeonaziclea
calycina. Ser 7 was not included in the TWINSPAN
analysis, but included a large patch of S. spontanczitn,
among which grew saplings of <30 cm gbh. The charred
stumps of trees larger than any found in the quadrat
suggest that this area is in an early stage of regeneration
following disturbance by fire. That sizeable areas of
central Sertung bear this Saccharzim/Ti~nonizismix is
indicative of recent and quite destructive disturbance
over considerable areas of the island.
9. Dysoxylum forest. -Specimens collected in 1979
and 1983 and initially identified at Bogor as Dyso,~j>lzim
purasiticzim (D. caulostachj~zim)have subsequently
been re-attributed to D. gazidichazidianzitn (D.amooroides)
(D. Mabberley personal comtnzinicatron 1986),
which was the first member of the genus observed,
being found on R. Kecil in 1932. We consider it highly
probable that the material collected in 1982 (Tagawa
1984. Tagawa et al. 1985). and also determined at Bogor.
will be found to belong to this species. and have
assumed this throughout.
The D~~so,~ylurn ongaudlchaudianzim-rich forest
Sertung. described by means of a quantitative survey
in 1982by Tagawa (1984. Tagawa et al. 1985). covered
the main ridge and east-facing slopes, commencing e0.5
km south of the spit. This forest type extended 0.5 km
farther south (Fig. 10)and was bounded to the west by
a deep11 incised gully. Individuals of D. gaudichaudlanzirrz
in this forest achieved quite large sizes, ranging
up to 95 m tall with a girth of 2 10 cm. Beneath the D.
gaudlchazidianu~ncanopy. Gnetum gnetnon was the
most abundant tree. with an understory of Ficus,fiilva,
F. septrca. Lezicosyke capirellara, Macaranga tanarius,
and occasional Titnonius compressicaulls. Tagawa et
al. (1985) suggest that approaching the coast, Terminalia
(,atuppa was mixing as a co-dominant with Dysosylutn,
in the manner of the T. carappa and T. compressicazilis
mix described above. The ground flora of
this forest was found to be denser than in the equivalent
forest on R. Kecil. with a tangled growth of Stenochlacna
palustris and ,VephroIep~shlrszitzila.
Gnetu~ngnemon is commonly associated with people
(its fruits are edible) and was planted in Handl's
garden on Rakata (Docters van Leeuwen 1936). LimVol.
59. No. 2
ited cultivation was practiced on Sertung for a while
prior to the 1952 eruption. and it is possible that it
may have been introduced to the island at that time.
R. Kecil
Examination of the coastal vegetation of R. Kecil in
1983 revealed communities consistent with those of
Sertung. and it was therefore felt unnecessary to quantify
them. This explains their absence from Fig. 8. The
true coastal communities are far less extensive than on
either of the larger islands. Conversely. as was found
on Sertung. the inland forests of this small, elongated
island do not entirely escape the influences of coastal
conditions. The plots enumerated on R. Kecil in 1983
were of two types. Ti~nonizisforest (group 0 110 in Fig.
8A) and Dj>so.xj~lzi~nforest (group 01 11).The third DCA
axis (not illustrated) may have been a reflection of a
Dyso,~ylumto Terminalia axis. i.e.. "inland" to "coastal"
forests of R. Kecil and Sertung. but due to the
peculiarities of sampling described. both extremes were
not recorded from either island. Thus. whereas Ser 4
and 10 (Terminalia-rich) appeared at the negative end
of the axis, Kec 1, 4, and 5 ( D ~ s o ~ ~ y l u ~ n - r i c h )were
placed at the positive end. This interpretation does
indicate. albeit tentatively, a third important gradient
of vegetational structure.
Coasral and near-coastal co~n~nunities.-Most of R.
Kecil is fringed by ash cliffs and lacks a well-developed
beach vegetation. a situation that has changed little in
the last 50 yr. Extensive growth of Pes-caprae seems
to be restricted to the gently shelving northern beach.
Behind this. a fringing forest included the common
coastal elements Tertninalla catappa, Pandanus tectorius,
Pre~nnacor~-~nbosa,and Hibiscus tiliaceus. Barrlngronia
asiatica was extremely scarce in the areas
examined. although Soeriatmaadja et al. (1985) recorded
it as common from an unspecified location on
the island. They also recorded Hernandia peltata, as
forming "consocies." including B. asiarica, T. carappa.
F ~ c u s j i l ~ . a ,and H. tlliaceus, which are broadly consistent
with the Terrninalia forests of Rakata and Sertung.
apart from the dominant role ascribed to H. peltata.
This is of interest. as such a stand-type was not
recorded in the 1982 or 1983 surveys, and the coastal
fringe areas of the northern half of the island explored
in 1983bore Terminalia catappa forest similar to that
described from Sertung.
1. Casuarina stands. -All three main islands of the
Krakatau group are more precipitous on the side facing
the interior of the prehistoric caldera. In the case of R.
Kecil. the inward slope also faces the predominant wave
direction. It is steep and rocky and remains clad in
Casziarina equisetlfolia. In addition, remnant stands of
old trees were noted from within a mixed forest of
Timonius compressicaulis, .Veonauclea calycina, and
D~~o.xylutngazidichaudianutn in the north of the island
(Fig. 10).
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKiTAU 79
FIG.12. T ~ ) ? Z O ~ I L ~ S forest on R. Kecil. Note the even-age structure of this young forest (T. Richards 1983).C O ~ ~ ~ I ~ ~ ~ S S I ( ~ I I I ~ / I S
It~land.forests.-The high scores of Tlnlonllts con?pr.r.s.sicau1i.s
in the R. Kecil plots caused them to remain
as a single group (01 1 in Fig. 8A) until the fourth level
of the TWINSPAN classification. The two subsequent
groups were characterized respectively by high scores
of T. cotnprc~ssicaulis(Kec 2. 3) and Dj~soxj~lltnlgaud~chaudiatlum(Kec
I . 4. 5).
1. Timonius forest. -The almost pure stands of Tin1on1u.sconlprrsszcaltlis
on Sertung were matched on
R. Kecil, where it was a dominant on high ground in
the south (Fig. 12).This forest was represented by two
very similar plots. Kec 2 and 3 (Fig. 7). In a 1225-mL
plot at Kec 3. 153 of the 163 stems (constituting 93%
of the basal area) were T. cotnprrssicaulis (Fig. 9). '4
forest of many small-stemmed trees (the largest was
only 89 cm gbh. and the great majority were between
35 and 50 cm gbh). it had the smallest stature of all
those described from the three islands (Bush and Whittaker
1986). It was clearly an immature forest at an
early stage of development. The only species that broke
the dominance of T. con~prrssicaulisin the canopy
were the invasive (and in these islands common coastal)
figs Ficus,fulvaand F. septica. The understory was
characterized by a greater variety of shrubs and sapling
trees. e.g.. .irdisia hutnilis. Leucosj.ke ca.r~itellara..Zfacaranga
ranarius, .l/elastonza affitlc~.Pipc3r aduncun~.
and perhaps the most important. Dj~sos~~lunigaud[chaurlianlrnl.
The latter were commonly =7 m tall.
with a girth of 17-23 cm. and were thrix-ing beneath
the T. con~pressica~tliscanopy. The ground Hora was
dominated by Stc.noc.hlac.na palustris and ~Vephro1epi.s
SPP.
The creeper Elac3agt1ltslatifbliawas also common in
the Tinlonius cotnpre.~sica~~/isforests of R. Kecil, providing
a dense. thorny ground cover and also. in parts.
matting the canopy. Interestingly. it is not common on
Rakata and Sertung. where S~nilavrrj31anica.and to
a lesser extent Fla,yt~llariainilica, respectively. appeared
to fill similar niches.
2. Dysoxylum ,forc>st.-Three plots were located in
Dj9so.uj91unzgaudichuudianutn forest. Kec 1. 4. and 5.
in the central and northern parts of the island. near the
main ridge at altitudes of = 100m. They were separated
from the other R. Kecil stands at the fourth TWINSPAN
le\-el (Fig. 8A). The ba values for D. ~gaudrchaudtanu~nranged
from 22% in Kec 1 and 51% in
Kec 5 to 76% in Kec 4. Kec 1 contained just two
specimens of D. gal~dichal~dianl~/~~.Both were very large
trees ( 162 and 254 cm gbh). and their presence accounts
for the location of the plot within the TWINSPAN
R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59. No. 2
framework. Nevertheless. that stand was somewhat different
from Kec 4 and 5, in that it was otherwise composed
entirely of Tirnor~iltscornpressicaulis (54.3%)and
.*r'eonauclea calycina (12.6%). This plot may represent
an intermediate stage between the Tirnonius-h'eonauclea-dominated
community described by Tagawa et al.
(1985) and the D. gaudichaudianunl-dominated forest
of Kec 4 and 5.
Kec 4 and 5 had the highest total ba-to-quadrat-area
ratios of the R. Kecil and Sertung plots (Bush and
Whittaker 1986: Fig. 3.2).indicative of the greater stature
of this forest type, which was comparable in this
respect to the inland forests of Rakata. Dyso.xy/unz gaudichaudianltnl
achieved a dominance in the canopy.
with T. conlpressicaulis the most important understory
species (Fig. 9). Few AT.caljrina were recorded from
these plots. In Kec 4. only 16 of the 58 trees measured
in the 900-m2plot were D. gaz~dichaudianunz,yet they
accounted for 76% of the ba. This compares with 33
specimens of T. compressicaulis, constituting only 21O/o
of the ba. The ranges in girth of the two species differ
in line with these figures, with many of the D. gaudichaudianum
exceeeding a gbh of 2.0 m, but the maximum
gbh of T. compressicaulis only 101 cm. Similarly.
D. gaudichaudianum achieved greater heights,
mostly exceeding 20 m. with the tallest measured
reaching 33 m. Beneath these specimens, T. compressicaulis,
Ficus montana, and F. tinctoria formed a canopy
at 10-12 m. This forest was relatively open in the
understory. with saplings of Buchanania arborescens,
F.fulva, F.septica and .tfacaranga tanarius, in addition
to the common T. compressicaulis and D. gaudichaudianur~z.In
total, 34 species of higher plants were recorded
in Kec 4 (900 mZ).including 10 pteridophytes,
which made up most of the ground cover. In particular,
Stenochlaena palustris was an important terrestrial
component in all three D. gaudichaudianum-rich plots.
Anak Krakatau IV appeared in the center of the
prehistoric caldera on 12 August 1930. Seedlings of
typical coastal species were described in 1932. but this
vegetation was destroyed by eruptions later in 1932-
1933, and in April 1934 only five species were found
(Docters van Leeuwen 1936). Further eruptions in July
1939 totally buried the island's vegetation (Dammerman
1948, Borssum Waalkes 1960), but the next botanical
observations were not made until June 1949,
when a beach vegetation on the northern part of the
island was examined. This consisted of young specimens
of herbs and ligneous plants, such as Barringtonia
asiarica. Calophyllum inophyllum, Cjperus pennatus,
Erj3thrina sp., Ipomoea pes-caprae, Pandanus tectorius,
and some 6 m high Casuarina equzset!folia. Further
inland, some scattered clumps ofSaccharum spontaneurn
were seen (Pijl 1949, Borssum Waalkes 1960).
In 1951, the vegetated area remained mostly limited
to the flat strip behind the beach on the east and north
sides of the island. The oldest part of this vegetation
was sampled by Borssum Waalkes (1960) and found
to be dominated by Spinifex littoreus, with Ipornoea
pes-caprae and Canavalia rnaritirna. Scattered bushes
and clumps of Saccharurn spontaneunz occurred within
this vegetation and the older Casuarina equiset~foliu
specimens were by then 10 m in height. There were
other small patches of slightly differing composition,
and on the slopes a vegetation of scattered tussocks of
S.spontaneurn persisted to an altitude of 25 m, and to
50 m in the erosion gullies. A species of moss and
several small ferns (e.g.,h'ephrolepis sp.)were also found
within these gullies. Between late August and 10 October
1952, eruptive activity covered this vegetation
in several metres of black ash. Only the skeletons of
the young C. equisetifolia trees rose above it, and Borssum
Waalkes (1960) concluded that all life on the island
may well have been killed. Vegetation development
has subsequently been affected by volcanic action,
for example in 1953, 1960-1961, 1972 and 1979-1982,
but mostly without direct observation. The only recent
botanical surveys have been in 1979. 1982, and 1983
(Barker and Richards 1982, 1986, Tagawa et al. 1985).
In 1979, the vegetated areas of Anak Krakatau
amounted to a few small patches around the eastern
coast and one large area covering the coastal foreland
on the eastern side. Barker and Richards (1982) examined
a transect extending from the beach into the
interior. The first 25 m was covered in Pes-caprae,
including species such as Ipornoea pes-caprae, Cassytha,fillformis,
and Canavalia maritima, and with some
Casuarina equisetifolia seedlings. There were some
young Barringtonia asiatica at the top of the beach,
but C. equiset~foliadominated the next zone inland in
almost pure stands. C. equisetlfolia is a light-demanding
species and in the more mature areas of woodland
its seedlings were absent, although there were young
specimens of, for example, Terminalia catappa, Calophj,llum
inophyllum, Hibiscus tilraceus, and Radermachera
glandulosa. The transect next crossed a (possibly
disturbed) patch of open grassland dominated by
Ischaemum muticum, in which some secondary forest
species were found, e.g., Dalbergia junghuhnir, Ficus
.ful~ta,F. septica, Morinda citrrfolia, and Neonauclea
calycina. Inland, as the marine deposits gave way to
volcanic deposits. the vegetation cover fell from nearly
100%to <5%, consisting of scattered Saccharum spontarzeunz
and C. equiset~fofoliawith some typical beach
plants and, on the sides of the erosion gullies. Eupatorium
odoratum. Imperata cylindrica, .tfelastoma a$
,fine, Kephrolepis hirsutula, and Pogonatherum paniceum
(Fig. 13). There appears to be a sharp physical
and/or chemical boundary between the beach and the
volcanic deposits on Anak Krakatau, such that a dense
vegetation cover has never been recorded on the latter
June 1989 RECOLONIZATION AND SUCCESSION OK KRAKATALI 8 1
FIG. 13. P~oncer\ egetatlon In a gull? on Anak Krakatau (T. R~chards1983)
(Fig. 14 and Barker and Richards 1986). From =130
m inland, the on14 vegetation consisted of scattered
clumps of S. spontatleuln.
Bq 1983, some di\.ersification of the forested area
was noted. with several new forest tree species, including
Titnot~ilrsconzpressicaulis. There had also been
a visible increase in the area of closed Ca~ztarir~a
cyui.rcf~/bliacanopq (Barker and Richards 1986). Se\--
cral lava flows dating from between 1963 and 1979
were examined by Tagawa (1984) in 1982 and were
found to be mostly devoid of plant life. Nevertheless.
where some volcanic ash had mixed with the 1973 lava
flow, Pitj.rogranz~nacalonzelat~os,~Vephrolepissp.. Ilnpetafa
c illr~dtrc a, Sacchat 10t1 rponiar~e~rtti,\fcIa5iot?zu
affrne,and Frclrs firha were found A similar but lounger
vegetat~on.of the tmo ferns onll. was reported from
comparable areas of the 1975 la\ a no\+
A clear gradient In arboreal communities with increasing
altitude has been established for Rakata. This
pattern was paralleled bq a similar gradient in bryophytc
communities. and bq temperature. humidity.
R. J. WHITTAKER ET AL Ecolog~calMonographs
Vol. 59. No. 2
FIG. 14. The closed canopy of Cas~rarinaequiset~fol~aforest on the south-eastem promontory of Anak Krakatau in 1983.
This photograph represents the most advanced vegetation yet recorded on this active volcano. Note that the vegetated area
is almost entirely restricted to the accreting coastal deposits, with only scattered clumps occurring inland. The island in the
background is R. Kecil (N. Barker 1983).
and soil properties (Fig. 2 and Forster 1982, Newsome
1982, 1986). The epiphytic cover of the uplands was
much more luxuriant and differed in composition from
the lowlands (e.g., see Appendix 111, Jones 1986b).The
change in tree species composition was less dramatic
than the alteration in structural appearance and epiphytic
cover, although the sudden rise of Scheflera
polybotrya as a dominant in the shrub layer was equally
notable. The main structural features were the squat
form of the trees and the merging of the ground, shrub.
and tree layers. Newsome (1982, 1986)and Shinagawa
et al. (1985) found no significant differences between
the lowland and upland soils in the levels of K, Na.
Al, Mg, Ca. P. and N. Despite an increased depth of
humus in the mossy forest (12 cm compared with O-
3 cm in the lowland forests: Newsome 1982), Bush
( 1 9 8 6 ~ )concluded that edaphic factors were not the
cause of stunting. Similar vegetation patterns on the
coastal Mount Victory in Papua New Guinea were
described by Taylor (1957)who reported an altitudinal
contraction of zones, with a change to dwarfed montane
(moss-covered) thicket at 900 m. The uppermost
100 m of Rakata is frequently shrouded in cloud, and
the gradients described in vegetation and environment
together suggest a transition to submontane or montane
mossy forest at ~ 5 5 0 - 6 0 0m. a much lower altitude
than the norm. Taylor (1957) suggests 2000 m
for the vegetational transition in the interior of Papua
New Guinea, while Whitmore (1984) observes that
clouds normally form around tropical peaks in excess
of 1200 m, but that this altitude limit is reduced on
offshore islands The cause of these effects is probably
best ascribed to coastal (1e , oceanic) contraction of
certain environmental gradients The plentiful atmospheric
moisture, high humidity. and the cooling influence
of the tropical seas result in the near permanent
presence of cloud in the upper parts, further lowering
temperatures Wind conditions near the summit may
also be important. especiallq with regard to the stunted
appearance of trees
The influence of geological variation on the vegetation
of the islands has not emerged as significant.
apart from its role in the differing initial colonization
patterns described on Anak Krakatau (Tagawa et a1
1985. Barker and Richards 1986, Newsome 1986)
These variations have more to do with the physical
than wlth the chemical properties of the substrate, and
indicate considerable differences in the rate of ecosqstem
development between scoria, ash, lava. and pumice
substrates
L7eLqetationdynamics and
environmental dynamics
The islands of the Krakatau group provide a set of
long-running tropical successions. These began as primarq
successions but now include various subseres or
secondarq successional elements The detailed surveys
of the 1979-1 984 period enable an update of the de-
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 83
scriptive summary schema o f Richards (1952),Whittaker
et al. (1984).and Tagawa et al. (1985).
Successional schema.-Tagawa et al. (1985) proposed
a summary scheme. relating to the entire island
group, which incorporates the vegetation communities
of Anak Krakatau as pioneer stages leading to midsuccessional
stages as found on the main islands in the
early part of the century. It is argued here that Anak
Krakatau is in several significant ways a poor analogue
for the early successions on the other islands. The alternative
schemata presented in Fig. 15 are intended
principally as historical summaries. W e have chosen
to deal separately with the successions on Rakata, and
on R. Kecil and Sertung. because o f the markedly different
course of post- 1883 events. W e have ignored,
for these purposes, the impact o f coastal erosion and
deposition, which may lead to the lateral migration o f
vegetation communities and ecotones. It is perhaps
paradoxical that the coastal succession is illustrated as
the simplest and most quickly realized o fall the islands'
seres. whereas the coastal fringe is actually one o f the
more dynamic environments. Fig. 15 reflects the essential
stability o fthe composition o fthe coastal communities.
The characteristic taxa became established
early and, despite the unstable nature o fthe coastlines,
relatively few have become extinct.
not appear to have differed.apart perhaps from the
19 19 fire. and the areas burned do not correspond to
all areas supporting Ficus-rich stands (compare Fig. 3
and Fig. 10).Alternatively. there may be an environmental
reason (e.g., aspect controlled climatic variation)
for the slower forest closure and subsequent
successional changes. Patchy seed dispersal o fF. pubznervis,
perhaps related to roost sites, may also be important
and, whatever the cause. it is apparent that a
number o f different successional pathways are being
followed on Rakata (Fig. 15A).
2. Dysoxylum.forest dorn~nance?-Theproposed role
o fDysoxylurn parasiticum as the next forest dominant
throughout the main islands (Tagawaet al. 1985)must
be viewed in the light o f its emended specific determination
to D. gaudichaudianurn (see Description o f
the Vegetation Communities o f 1979-1984: Sertung:
Inland Forests: Dyso,~ylumForests. above).D. parasltlcum
is apparently a canopy component o f mature
forest (Kartawinata 1977,cf.Whitmore 1984),whereas
D. gaudichaudianurn is a widely dispersed, early or
intermediate sera1 species (Mabberley.personal comtnunrcatron).
With the possible exception o f Planchonella
duclrtan, this re-identificationremoves the only
"primary forest" tree (cf.Whittaker et al. 1984) from
the floral list o f Krakatau (T. C. Whitmore. personal
Tagawa et al. (1985)have proposed that Dj~so.~j~/umcornmunication).
forest is the most advanced community o f the Krakatau
islands, and that both Timonius cornpressicaulis
and Neonauclea calycina forest will be dominated by
D. gaudichaudianurn in time. They suggest that the
order and timing o farrival on each island o fthese three
dominants can account for the broad differences in
vegetation between the islands. In examining these hypotheses.
three aspects are o f particular importance:
first, the spatial extent o f sampling has now been extended,
providing new data on each island:second, the
status o f the D~~soxj~lumforest may be less advanced
than previously thought;and third. the role o fash-falls
from Anak Krakatau may have differed significantly
between islands.
1 . Successional path~vays on Rakata.-We have
made a distinction between the lowland. near-coastal
secondary forest o f southeast Rakata. dominated by
hTeonaucleacalycina and a much less extensive submontane
secondary forest (Ficus ribes, etc.) near the
peak (Fig. 15A). The gradation between lowland and
upland forest was identifiedas early as the 1920s (Docters
van Leeuwen 1929). as well as in the surveys o f
195 1 and 1979 (Whittaker 1982). While no sharp
boundaries were evident in these surveys, an attempt
has been made to show the approximate distributions
o f the main forest types in Fig. 10. U p to 1932 the
western parts o f Rakata. from which the Ficus pubinervis-richforest
was sampled in 1983,were apparently
slower to develop a forest cover than the eastern (N.
calycina-rich)areas (Doctersvan Leeuwen 1936).The
post- 1883 environmental histories of these areas do
Despite the success o fDyso,~ylumgaudichaudianurn
on Sertung and R. Kecil, it is still a comparatively rare
tree on Rakata, where it appeared to be principally
near-coastal in its distribution. Even as a seedling it
was only recorded from Rak 1. 9. 10. 1 1. 12 and 15.
O f these only Rak 15 (250 m ) was at an altitude >40
m. This site lay close to the northwestern bluffo f Rakata.
and was therefore more exposed to coastal influences
than a site o fcorresponding altitude on the eastern
side o f the island The only sites where D
gaud~chaud~anurnwas recorded as being larger than a
sapling were Rak 1 (2.7% ba), Rak 10 (0.3O/o ba),and
Rak 1 1 (1.1O/oba) There seems little evidence to suggest
that D gaudzchaudranurnis in the process o f invading
the higher altitude or Ficus-rich forests o f Rakata.
3. Sequence of arrr~alofforest dornznants -Part o f
the reason for suggesting that Dl-soxvlum-dominated
forest would be a natural successor to the existing forests
o f Rakata was the inferred pattern of succession
on R. Kecil and Sertung and the sequence o farrival o f
potentially dominant species on each island (Tagawa
et al. 1985). In support o f this view. Neonauclea calycina
was first recorded on Rakata in 1905. the only
island on which it is widespread as a forest dominant.
but was not found on Sertung until 1920. nor on R.
Kecil until 1929 (Appendix I). Timonius compresslcaulis
was first found in 1929 in a single gully on Rakata.,and
in the same year on R. Kecil, where it was
noted to be already common in the interior (Docters
van Leeuwen 1936).Nevertheless, it is improbable that
these differencesin the timing o f initial establishment
84 R. J. WHITTAKER ET AL. Ecolog~calMonographs
Vol. 5 0 , No. 2
@Pes-caprae Terrninalia Ficus Neonauclea Mossy forest
Schefflera (& Cyrtaildra)

beach Barringtonia puhinervn forest Ficus 8 scrub wlth low trees lga3 

cornmun~ty forest forest Neonauciea etc.
A k
T TNeon;forist \Neonauclea Schefflera 8Cyrtandra 1951foyst scrub
t
Neonauclea Cyrtandra
Macaranga-Ficus forest scrub 1932
T TMature Saccharurn Cyrtandra Cyrtandra Saccharurn
1919 

with scattered trees scrub / 8 ferns
A / A
A \ ' / I
Tern~inaiia Casuarina
Cyrtandra?
I 1906
etc
Pioneer grasses A
I
(Saccharurn) I 1
I I
1897
I I 

Pioneer Ferns 8 Ferns & Ferns & 

1886 

Pes-caprae Cyanophyceae Cyanophyceae Cyanophyceae
COASTAL LOWER REGION UPPER REGION
SUMMIT
(to 550 m) (above 550 m)
Pes-caprae Casuarina Terminalla Timonius Dysoxylurn 1983
beach wood forest forest forest
community
Casuarina Terrninalia
T
t
/ Pioneer grasses
Pes-caprae 8
Casuarina tFerns & Cyanophyceae
COASTAL INLAND
FIG.15. Principal successional pathways on (A) Rakata and (B) Sertung and R. Kecil. (A) Rakata has experienced 100 yr
of ecosystem development, apparently uninterrupted by the volcanic disturbance that has hit the other islands. In 1979-1983
the inland forests consisted of a mosaic of stands in which Neonauclea calycina, Ficus pubinervis, and F. tinctoria were
dominant, either singly or in varying combinations, with a transition to a submontane mossy forest (F. ribes, Saurauia
nudiflora, Villebrunea rubescens) at about 550-600 m altitude. Adapted from Whittaker et al. 1984. (B) Eruptive activity of
Anak Krakatau has interrupted forest development on Sertungand R. Kecil on several occasions since 1930. The more severe
events caused a return to open grassland communities dominated by Saccharum spontaneum (as indicated downward pointing
arrows). It is postulated that such disturbance induced a deflection from the Macaranga-Ficus pathway, to Timonius followed
by D~~o.uylumforest types, although damage has presumably not been completely evenly spread (see Fig. 3). Dates indicate
the time at which vegetation types were first recorded.
85June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
are wholly responsible for the absence of 'V. ca1j)crna
forest on R. Kecil. and of T compress~caulzsforest on
Rakata. Rather the available evidence (small stature
of much of the T cornpress~caulrsforest, etc.) supports
a disturbance-related explanation for the presence of
the T compressrcaulrs forest (as Fig. 15B) This applies
not only to R. Kecil. but also to Sertung, on which it
was first recorded as late as 1982. In the case of D.
gaudichaudianum, the recorded order of arrival within
the group is clearly unrelated to the distribution of
forests it dominates. as it is dominant on R. Kecil and
Sertung, but not on Rakata, and the order of "arrival"
was R. Kecil 1932, Rakata 1979, and Sertung 1982.
Critical to this debate is that survey intervals. extents,
and efficiencies have varied greatly among the
islands (Table 2 and Whittaker and Richards 1986).
For example, with regard to the arrival times of A'.
calycina (above). between 1897 and 1929 collecting
was undertaken on R. Kecil on only two separate days.
Thus. dates on which particular species have first been
recorded on each island cannot be assumed to mirror
accurately the order of their arrival. The unequivocal
evidence can be summarized as follows: T. cornpressicaulis
was established in substantial numbers on R.
Kecil earlier than on Rakata: N. calycina was well established
on Rakata by the time T.compressicaul~swas
first found on that island; and Dvsoxvlurn gaudzchaudianurn
was the last found on all three islands (Appendix
I). These observations thus do not provide unequivocal
support for an explanation for inter-island
differences based on arrival times of the three domi-
nants.
4. lrnportance o f continued volcanism. -The distribution
of these forest dominants may also be explained
by different autecological requirements. Tagawa et al.
(1985)reported that Dj)so,~j)lumgaudichaudianum occupied
predominantly flat areas, east-facing slopes and
ravines, which were sites of a relatively high soil moisture
content. Tirnonius cornpressicaulis forest was reported
to occupy relatively drier sites on west- and
north-facing slopes. In our survey in 1983 and 1984,
however. extensive areas along the spines of Sertung
and R. Kecil were recorded as supporting a virtually
monospecific canopy of T. compress~caul~sforest, in
which D gaudrchaudranurn were present as understory
saplings. The slightly moister soils reported by Tagawa
et al. (1985) from beneath the D gaud~chaudzanum
forest may well reflect an increased soil maturity. perhaps
the result of a longer period of uninterrupted forest
development and pedogenesis, than below the T
cornpressrcaulrsforest. In short, the patchy distnbution
of D gaud~chaudzanumas a mature forest dominant,
combined with its widespread occurrence as a sapling.
would be more consistent with a response to past environmental
events (cf. Shinagawa et al. 1984), rather
than to time-independent edaphic limitations. On several
occasions (e.g.. 1930. 1932, 1934. 1935. 1952,
1953) since the 1883 "sterilization," Anak Krakatau
has caused the partial destruction of areas of forest on
both Sertung and R . Kecil. but apparently not on Rakata
(see Physical Environment: Volcanic and Tectonic
Activity since 1883. above: Fig. 3). Parts of both islands
have received a significant fall of ash on five or
six separate occasions (Shinagawa et al. 1984). It is
suggested here that volcanism is the key factor in understanding
the present distribution of Dj)so,~ylum
gaudichaudianum and Tirnoniuscompressicaulisforest
on Sertung and R. Kecil, and that T. compressicaulis
has acted as a "nursery crop." modifying the environment
and enabling the establishment of the later
successional D. gaudichaudianum (Fig. 15B).
5. Successional deflection.-The damage caused to
the vegetation of Sertung and R. Kecil by the eruptions
of Anak Krakatau has been varied. Docters van Leeuwen
(1936) and Borssum Waalkes (1960) regarded the
damage they observed as not comparable to the sterilization
of 1883. Both considered that "recovery"
would only take a few years. providing no further disturbance
took place, although in fact further damage
did occur shortly after both visits. The potential of this
environment to support the recovery of a vegetative
cover following disturbance should not be underestimated.
For instance. Docters van Leeuwen (1936) described
a stand of Casuarina equisetifolia trees -1 yr
old and 3 m tall. which developed in 4 yr into a woodland
with trees >20 nl tall. Similarly, in July 1924, 5-
6 m high Macaranga tanarius were found in an area
that had been cleared for a campsite in January 1922.
Yet ifthe null hypothesis that volcanic activity has not
caused mid- or long-term alteration to vegetation development
were to stand, why should the forests of
Sertung and R. Kecil not have reached a stature equivalent
to those of Rakata? Although some stands in the
Dyso.~j)lumgaudichaudianum-dominated parts contain
some large trees. none is as massive as those recorded
from the southern side of Rakata. Moreover.
Tirnonius cornpressicaulis specimens of 200 cm gbh
were recorded from Rakata. while the largest recorded
from the surveys of Sertung and R. Kecil was only 120
cm gbh. There was also a marked difference in the
stature of this species between differing patches of forest
on R. Kecil and Sertung. In the near-monotypic T.
compressicaulis forest of Kec 3, the largest trunk was
89 cm gbh. and only 4 out of 143 specimens were of
>70 cm gbh. Similar data were recorded from Sertung
plots Ser 12 and 13. In contrast. the D. gaudichaudianurn
forest, as exemplified by Kec 4. contained fewer
individuals of T.cornpressicaulis, but 30°/o were >70
cm gbh, with a maximum of 120cm gbh. These patches
must represent populations of differing ages. The stature
of some of the T.cornpressicaulis patches described
would suggest that it may have seeded in as late as the
early 1970s. It is ideally suited to the rapid invasion
of bare ground, its seeds are bird dispersed, it grows
rapidly. and can flower when only 1 m tall (Corner
1952). The presence of patches of Saccharum spon-
86 R. J. WHITT'AKER ET AL. Ecological Monographs
taneurn within some parts of the T. compressicaulis
forest (e.g.. Ser 7). in which young seedlings of T. cornpressicaulrs
were observed, suggests that disruption is
still taking place, and that the S. spontaneum patches
represent the first stages of recovery. This model is
supported by soils data that reveal several new starts
to pedogenesis (Shinagawa et al. 1984). Moreover. in
some areas at least, the "disturbance" horizons were
very recent (cf. Simkin and Fiske 1983:359).
The presence of stands of D. gaudichaudianum may
also relate to volcanic disturbance. It is a relatively
recent arrival on the islands. is capable of rapid growth
in the right circumstances, is characteristic of disturbed
sites, and certainly was not an important constituent
of the forests prior to the eruptions of the 1930s. We
suggest that the disruption of the forest communities
of Sertung and R. Kecil enabled a more rapid spread
of this species. Furthermore, the well-defined edge to
the present D. gaudichaudianum forests suggests that
they may be the remnants of a more extensive forest,
which was destroyed by one or other of the eruptive
episodes. Instead of Sertung and R. Kecil having the
ecologically most mature forests of the islands (Tagawa
et al. 1985).they have, compared to Rakata, very young
forests.
The importance of variations in seed availability
should not, however. be dismissed: the current dominants
have only achieved that status by having a sufficient
seed supply and transport to enable invasion
when the opportunity became available. In addition to
the species discussed. there have clearly been many
others that have shown uneven patterns of arrival both
between and within islands (Docters van Leeuwen
1936). For example. Ficus pubinervis, now a "dominant"
in areas on Rakata, appears to owe its position
to chance early arrival by bird/bat transport in that
area. Similarly, there was a patch of forest in northern
Sertung (Ser 10 and 11). in which the otherwise uncommon
Gneturngnemon was the principal understory
species. This species may well owe its distribution to
introduction by humans. The forest creeper Smilax
zeylanlca, a late arrival but now common on Rakata.
has not been recorded on Sertung or R. Kecil (Appendix
I). On Sertung, Cayratia rr~folia,Flagellaria indica,
and Hoya di~xersifoliafill a similar role to S. zeylanica.
In the case of R. Kecil, another late arrival. Elaeagnus
latifolia, achieves an importance it lacks on the other
islands, and in places (e.g., Kec 3) can be so abundant
as almost to obscure the foliage of the trees.
Although the extent of ash-fall and forest damage
has been incompletely documented. different-aged forests
occurring in well-defined areas of the island indicate
a clear causal link between volcanic events and
the current patterns of vegetation type. Further corroborative
data emerge from analyses of the floral data,
in which the overall richnesses of the R. Kecil and
Sertung assemblages do not appear to have increased
since the 1920s. in contrast to the pattern for Rakata.
Vol. 59. No. 2
which has continued to rise (Non-cumulative species
totals, below). The disturbances have clearly varied in
intensity, distribution. and interval. but their combined
impact has been not only to slow the progression
towards richer mature forest. but also to deflect the
main successional pathways of the communities of the
interior (Fig. 8B).
The stature attained by Dyso,~ylumgaudichaudianum
on Sertung and R. Kecil suggests that this species
may become an important component in the nearcoastal
forest of Rakata. However, as there is no sign
of this tree spreading in the forests at higher altitudes,
or among the Ficus pubinervis and F. tinctoria forests.
it would be rash to assume that it is the natural successor
as the forest dominant over the greater part of
Rakata. Rather it is anticipated that it will contribute
to an increased forest diversification and that the period
of large areas of monotonous forest numerically
dominated by single species may give way to a more
patchy mosaic.
Comparison of the early successions on old and new
Krakatau islands.-It has been proposed that Anak
Krakatau provides an analogue for the post-1883 period
on the main islands. which might fill gaps in the
early years of study. in particular of the fauna (Dammerman
1948. Thornton 1984). It is our contention,
however. that there are such major environmental and
ecological differences that the new island offers only a
poor representation of the early habitats on the other
islands.
The importance of ferns in the earliest stages of the
succession on Rakata was such that 1 1 of the 24 species
of higher plants found by Treub in 1886 were pteridophytes.
More important, they were responsible for
the majority of the vegetation cover of the interior.
The "soil surface" was principally of little-altered ash,
and the ferns and the few other plants of the interior
were species typical of minimally developed soils and
exposed localities (Appendix I, Docters van Leeuwen
1936). In contrast, only six species of ferns have been
recorded from Anak Krakatau (Appendix 11).and they
have never been an important constituent of the vegetation
cover. One of the critical factors differentiating
the immediate post-1883 successions of the main islands
and the post- 1930 succession of Anak Krakatau
is the presence of nearby sources of propagules and
some of the animal agents of their dispersal. Thus the
rain of propagules reaching Anak Krakatau is likely to
differ both qualitatively and quantitatively from the
post-1883 period. Nearly all of the species found on
Anak Krakatau are known elsewhere in the group (below.
Appendices I and 11). A further major difference
is the volcanic activity of Anak Krakatau. It has been
both regularly noxious and spasmodically violent, and
has caused repeated disruption of the developing vegetation
cover. on occasions, such as in 1952, amounting
to the virtual elimination of the vegetation (Borssum
Waalkes 1960).This history of disruption. in which no
June 1989 RECOLONIZATION AND ST.JCCESSION ON KRAKATAU 87
fixed starting date can be identified, contrasts with the
quiescent period between 1883 and 1927, the early
years of ecosystem development on Rakata, Sertung,
and R. Kecil.
Active gas vents were seen in 1984 near the crest of
the outer ridge of the volcano. and in view of the extremely
slow upslope spread of vegetation, gas release
co~lldbe one of the factors inhibiting vegetation development.
Pyroclastic fallout was also observed over
large parts of the interior in 1979. Perhaps a key factor,
however. in the remarkably poor colonization away
from the spit is the nature of the soil material. in particular
the structure of the surface (Newsome 1986).
Borssum Waalkes (1960) suggested that the hard ash
of Anak Krakatau in 1951-1952 would be relatively
impermeable to water and to penetration by the roots
of seedlings. while the indurated crust observed on the
surface of the outer cone in 1979-1 983 contrasts with
the friable ash cover recorded post- 1883 by Verbeek
(I885) and Treub (1888). Mineralogical differences between
the 1883 ashes and those from Anak Krakatau
(Shinagawa et al. 1984) are of unknown importance.
The two cuspate forelands where the vast majority
of the island's vegetation and resident fauna occur are
principally marine deposits. and are therefore atypical
of the rest of the island and of the majority of the
Krakatau island group. The very slow spread of vegetation
inland from these marine deposits, because of
substrate and/or disturbance, has no parallel in either
the post-1883 period, nor the more recent events on
Sertungand R. Kecil. For these reasons, it is considered
inappropriate to promote Anak Krakatau as an analogue
for the early post-l 883 period, and attempts to
incorporate the two together in successional schema
may be misleading.
Introduction
There is a long tradition of ecological and biogeographical
interest in island biotas, much of it concerned
with the nature and stability of island assemblages (e.g.,
see Gorman 1979, Williamson 1981). Krakatau provides
a "natural experiment" of known starting point
in the colonization of insular areas by both plants and
animals. The early plant and bird data for the group
as a whole were examined by MacArthur and Wilson
(1967) in the context of their "Equilibrium Theory of
Island Biogeography": by 1934 there was no sign of a
decline in the rate of plant colonization, as predicted
by their theory in its simplest form (MacArthur and
Wilson 1967:48). Furthermore. the apparent levelling
of numbers of bird species now appears to have been
a temporary feature of the data, as successional changes
in the vegetation led to the loss of bird species of open
habitat during the 1920s and 1930s. followed by the
gain of more forest species (see Hoogenverf 1953.
Thornton 1984). Surveys in 1951-1952. 1979, and
1982-1984 provide new data for analysis of the accumulation
and turnover of plant species over a
uniquely long time scale and enable a fresh look at the
relevance of island biogeographic theory.
The first question is whether there has been a significant
trend toward dynamic equilibrium of the form
predicted by MacArthur and Wilson (1967)? A second
facet of their model is also of interest: the hypothesis
that species number should be dependent on island
area, which they employed in part as a surrogate for
habitat diversity. Recent literature. as exemplified by
Buckiey's (1982. 1985)"habitat-unit" model of island
biogeography, has indicated that the possession of particular
identifiable habitat types may be critical, rather
than a more general measure of habitat diversity. On
the same theme, Bush (1986b) has noted that the butterfly
species richness of the Krakatau islands is more
closely related to the presence and extent of specific
vegetation communities, than to island size or overall
habitat diversity. It may thus be an opportune point
to revive the analyses initiated by Ernst (1908) and
Docters van Leeuwen (1936) of the roles of habitat
type and dispersal mechanism in the floral recolonization.
There is no a priori reason, however. to suppose
equivalent controls on the faunal and floral elements.
The broadly differing life history characteristics of fauna
and flora (cf. Sauer 1969, Whittaker and Flenley
1982), and the manner in which they interact, may
inhibit the successful incorporation of both into a single
unifying framework for island biogeographical analy-
sis.
There are a number of constraints regarding the analysis
of the Krakatau data and the derivation of rates
of immigration, extinction. and turnover. First, there
is the matter of the definition of immigration and extinction
events, which may differ among taxa. especially
when comparing faunal and floral data. Second,
data quality is a serious and for some purposes unquantifiable
problem. Third, survey intervals have varied
greatly during the study period 1883-1983, and
have differed among islands. Fourth, Anak Krakatau
has added new habitats within the group and has disrupted
and deflected the progress of succession on R.
Kecil and Sertung. This means that there are now substantial
differences in the ages and complexities ofcommunities
within the group, and, with the exception of
Rakata, there can no longer be assumed to be a fixed
starting point to re-colonization (Richards 1986a).Perhaps
the most fundamental consideration. clearly established
by the foregoing sections. is the key role of
successional processes in the floral history.
It is thus necessary to establish the nature and quality
of the available data, a problem hindered by the emotive
tone of some of the Krakatau literature (see Backer
1929. 1930, Docters van Leeuwen 1936). The weight
of evidence presented by Docters van Leeuwen (1936)
is convincing for the complete or near-complete sterilization
of the islands. for the long-distance transport
of propagules to the islands, and for the processes of
88 R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59. No. 2
TABLE2. Plant collecting on the Krakatau islands. Principal sources: Docters van Leeuwen (1936), Boedijn (1940). van
Borssum Waalkes (1960). Whittaker and Flenley (1982),Tagawa et al. (1984).
Anak
Collection period Principal collector* Year Rakata Sertung R. Kecil Krakatau
Time spent by collector (dayst)
seen
1886
1897 I
(Verbeek)
(Cotteau)
Treub
Boerlage
Penzig
Ernst
Ernst
Backer
DvL
DvL
DvL
DvL
DvL
DvL
DvL
DvL
DvL
Boedijn
vBW
vBW
Hull 1
Tagawa
Hull 2
Bush
* DvL = Docters van Leeuwen.In 1932-1934 Boedijn made six visits to the group, each of 5 or 6 d. but collectedprincipally
lower plants. vBW = van Borssum Waalkes. Bush collected a few species as part of the 1984 La Trobe Expedition: these
have been included in the 1983 survey.
t' Units are days unless marked "h" (hour) or "+" (short but unspecified time).
vegetation succession described above; however, he
clearly set out to support the worth of the botanical
studies, and to argue the various surveys to be as complete
as the evidence would allow. The general quality
of the evidence presented appears from a retrospective
viewpoint to be comrncndable, but the account and
interpretations are perhaps colored by the vitriolic attack
made by Backer (1929) (see review by Hill 1930).
We therefore paid considerable attention to the extents
and efficacies of the floral surveys.
Floral SUYI'PJ~S1883-1984
The number of collectors, their experience. the time
spent on each island, and the area covered have not
been uniform. Given the nature of the terrain it would
be difficult to achieve controlled survey conditions were
that aim rigorously pursued, but for many surveys it
is difficult to establish even the number of days spent
collecting (Whittaker and Richards 1986).
Rakata.-Verbeek, who reached the summit in October
1883, and Cotteau, in May 1884, found no evidence
of plant life (Verbeek 1885. Docters van Leeuwen
1936). Treub collected the first plants from Zwarte
Hoek beach and the lower parts of the interior in 1886
(Table 2). The early savanna vegetation was extremely
difficult to penetrate: Ernst (1908) reached only 50 m
altitude in his 1906 survey, while Backer (1909) extended
the trail up to 400 m in 1908.
Docters van Leeuwen (1936) visited the island several
times between 1919 and 1931 (Table 2). spending
most effort on the southeast side. On each trip but his
last he made an ascent to the summit and, except in
1929, collected from both beach and interior floras.
His last visit to the southeast was on 1 March 1931,
when he reached 300 m altitude. He did not camp on
the north side, but landed several times at Zwarte Hoek,
where he collected from the beach and the interior. He
also penetrated into west and northeast Rakata from
the landing points on the southeast side and from Zwarte
Hoek, but is not specific as to when and for how long
(Docters van Leeuwen 1936).
Boedijn (1940) collected mainly lower plants in six
visits to the islands between 1932 and 1934. On each
occasion he visited both the southeast side of Rakata
and Zwarte Hoek. The next botanical study was not
until 1951. when Borssum Waalkes (1960) made several
excursions along the shore and into the interior,
including the summit area. The first phase of the Hull
University-Krakatoa Centenary Expedition spent 16
d on the south side of Rakata in 1979, collecting being
carried out by up to three separate groups throughout
the period (Flenley 1980). A visit was also made to
Zwarte Hoek and to an area of shoreline on the northeast
side. Tagawa's 1982 expedition spent 7 d in various
research work, including plant collection (Tagawa
1984).The second phase of the Hull Expedition camped
at Zwarte Hoek. and examined mostly those areas not
investigated in 1979 and 1982.
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 89
Sertung.-Cotteau landed on Sertung on 26 May
1884 and found no plant life. The expeditions of Penzig,
Ernst. and Backer each landed for less than a day
on Sertung. Ernst (1908:37) actually specifies his collection
of 42 species to have been made by ". . . two
of us during a visit of barely one hour. . . ." Docters
van Leeuwen (1936) principally collected from the
northern end of the island, exploring the beach and
part of the interior. His main collecting effort was made
in 1920,when he traversed about one-third of the length
of the island. reaching an altitude of % 150 m. His only
exploration of the south was made in 1929. Borssum
Waalkes' (1954, 1960)two brief visits were both to the
northern end, the second after the vegetation was severely
damaged by volcanic eruptions. Tagawa's (1984)
expedition spent % 1 1d in various studieson the island,
and appears to have collected exclusively from the
northern end of the island. The second phase of the
Hull Expedition (Bush et al. 1986a) extended the area
studied by Tagawa to include the southern end of the
island.
R. Kecil. -Cotteau landed briefly and again recorded
no plant life (Table 2). The collection of Boerlage in
1896was made in a single day, during which he reached
the highest point of the island. He duplicated among
his collection all the species collected by Nolthenius (a
nonbotanist) during a longer period in the same year.
Penzig, in 1897, collected from the beach and from the
north end, as did Backer in the following year. Docters
van Leeuwen's visits spanned 1928 to 1932, and van
der Pijl and Boedijn also visited the island in the 1932-
1934 period, finding a few additional species (Docters
van Leeuwen 1936, Boedijn 1940). Tagawa's group
spent about 7 d in various investigations on the island
in 1982, apparently collecting mainly from the northeast
and central southwest (Tagawa 1984). The subsequent
phase of the Hull Expedition concentrated on
extending the 1982 survey. An additional survey of R.
Kecil was made by Soeriaatmajda et al. (1985) in 1982:
however. their species determinations contain significant
anomalies of taxonomy from the rest of the literature,
and. in view of the need for confirmation. their
reported taxa have not been incorporated into Appendix
I.
Anak Krakatau.-The first botanical records from
Anak Krakatau are from 1932. when three separate
but brief collecting trips were made. Eruptions subsequently
wiped out the seedling flora, and only two
species were found by Boedijn in 1933. This interrupted
pattern continued, and the flora sampled in 1949
and 1951 by van der Pijl(1949) and Borssum Waalkes
(1960) was wiped out in 1952. Barker (University of
Hull) spent 3 d in vegetational survey and plant collecting
in September 1979. This visit was followed by
5 days of investigation by the Kagoshima group in
1982, and a further 7 d by Barker in July 1983. The
1979 to 1983 studies constitute a virtually complete
floristic survey.
Although it is regrettable that the floral surveys have
not been conducted on a standardized basis, it is also
clear that in the early years the vegetation was indeed
very species-poor and monotonous. Thus, although
Treub (1888) explored only a small part of the interior
of Rakata in 1886. this deficiency is balanced by the
obvious species-poverty of the vegetation he described
(Docters van Leeuwen 1936). Similarly, he collected
from only one beach, a sheltered bay at Zwarte Hoek.
but there were very few such reasonably stable beach
environments at the time. all other areas being narrow
strips fronting perpendicular tuff-walls (Docters van
Leeuwen 1936).Thus his total of 24-26 species is probably
a reasonable indication ofthe diversity of the flora
at the time.
Very little of the interior of Rakata was explored in
1906 (Ernst 1908). yet on extending the trail from the
50 m altitude reached by Ernst up to 400 m altitude
in 1908, Backer (1909) found only 10 new species.
Docters van Leeuwen (1936) interpreted this as evidence
of the continued poverty of the flora, which remained
a feature when he first visited the islands in
1919.
Up to 1919 and even later it ~vasa striking-fact that
the vegetation was vcrj. monotonous. One could wander.for
hours through the ravines and over the ridges
without jinding a new species, after having collected
everything at the beginning of the excursion. . . .
(Docters van Leeuwen 1936:86)
Nonetheless, poor though the flora may have been.
the species totals for the early years cannot be argued
to be complete. While Docters van Leeuwen's surveys
were much more thorough. even his treatment was not
standardized. For example, the majority of the survey
effort on Sertung was carried out in 1919-1 920. whereas
he did not visit R. Kecil until 1928 (Table 2). Also,
the central section of Sertung appears not to have been
explored botanically at all, due to the extreme difficulty
of the terrain, until penetrated by Bush in 1984. His
observations provide no reason to suggest a radically
different flora in the central section of the island, but
effectively only a reduced area of the island has been
involved in sampling. Only on the much smaller (but
disrupted) Anak Krakatau can we assume that a thorough
investigation of the entire vegetated area of an
island was carried out. Each census on the main islands
must be considered as only a sample of the total species
present. It is clear from the quantitativesampling (Bush
and Whittaker 1986) that many tree species occur as
rare individuals scattered in a matrix of a few common
species. It is likely that some will always be missed. If
each survey were then to sample only % 80-90% of the
total flora of an island (cf. Nilsson and Nilsson 1985).
the resulting "pseudo-turnover" among the less common
species could account for a high proportion of the
RAKATA RAW DATA.
13 INTERVALS
..... RAKATA
6 INTERVALS
RAKATA
2 INTERVALS
- - - RAKATA SERTUNG,+
R KECIL. 2 INTERVALS
y SURVEY POINTS
' 1 ' I ' 8
1 I, ,I
FIG.1 6 Numbers ofnew species of higher plants recorded
over a variety of intervals. expressed as an annual rate. These
figures exclude re-invasions. Data from Table 3.
expected real turnover at "equilibrium." This is in itself
another clear argument against attempting to use
floral data to test island biogeographic theories without
very careful assessment of data quality. In addition to
these problems, taxonomic uncertainties (Appendix I,
Bush et al. 1986a:214-2 16) have resulted in a range
of possible values for species number calculations. The
nature of the data necessitates a cautious approach to
their analysis: there is much that is interpretative rather
than sound statistics.
Survey interval
The number of surveys in a given period may clearly
influence the efficiency of the sampling. When the surveys
have been very close together there is often a
strong case for combining them. They have tended to
overlap in personnel, who have concentrated during
later excursions on searching out new areas and species
not found on their previous visit (Whittaker and Richards
1986). Conversely, they may ignore areas searched,
or species known to have been collected, on their previous
visit: indeed it is probably more difficult to assess
the true pattern of species losses than gains. Thus by
considering such surveys as independent. species turnover
may be artificially increased. while if the data are
'AKER ET AL. Ecolog~calMonographs
Val. 59. No. 2
combined. the efficiency of the combined surveys is
much improved. If we first examine data for each separate
survey, following the approach of Whittaker and
Flenley (1982), the smoothing effect of subsequently
calculating immigration rates over greater intervals.
ignoring intervening data, can be seen (Fig. 16). Interestingly
the immigration peak of the 1920s remains,
despite the removal of adjacent survey data. This peak
is therefore not simply the product of increased frequency
of surveys. but is likely to reflect an important
phase of the recovery process. Despite thorough survey
efforts of the 1979-1 983 period, the number of new
species found is lower over the last 50 yr than over the
first 50 yr, a pattern repeated when data from the whole
island group (Rakata, Sertung, and R. Kecil) are considered.
This simple form of analysis can be improved
by the use of combined survey data for 1979-1983, as
developed in analyses below.
Dejinition of immigration and
extinction events
In studies of island biogeography various criteria
have been proposed to define immigration and extinction
events (reviewed in Williamson 19811,but in this
study the data take the most basic form, viz.. simple
lists of plant species that have been collected and identified
in a particular year (Appendices I and 11). Such
a list takes no note of the abundance of a species, and
can include a seedling colonist not yet independent of
its parental resources, or can exclude a forest giant that
could not be climbed for the necessary specimen ma-
terial.
The term "extinction" is used throughout in the local,
island biogeographical sense of the loss of a species
from an island. Whittaker and Flenley (1982), Whittaker
et al. (1984) and Richards (1986a, b) calculated
extinction on the basis of the lack of positive evidence
for the presence of a species in a particular survey. For
most plant species, extinction events can rarely be
proven for areas of the size of the Krakatau islands,
and artefactual specieslosses may lead to overestimates
of extinction and thus of turnover. In this paper we
make use of an alternative model. assuming minimal
turnover. i.e.. in calculating "extinction" a species is
only counted as having gone extinct if not found in any
survey subsequent to the survey in question. This assumes
that species simply went unrecorded rather than
becoming extinct and re-invading. Although a small
proportion of species, e.g., coastal ephemerals, may
indeed have been lost and then re-invaded, this assumption
probably fits the great majority of cases. In
particular, this can be argued for species of the interior
forests of Rakata, such as Ficus hispida and Smilax
zej-lanica, which, given their autecology and current
numbers, are highly unlikely to have gone extinct since
their initial recorded establishment, despite the lack of
a positive record in every survey. It should be noted,
however, that this approach is dependent on the further
June 1989 RECOLONIZATION AND SC[CCESSION ON KRAKATAU 9 1
assumption that the 1979-1983 sample is a relatively
efficient and unbiased sample.
Floral assemblages and the
cumulative curve of colonization
The data in Appendices I and I1 provide a complete
revised account of the higher plant floras of the Krakatau
islands. Summary data are given in Table 3. Lists
are also available for the mycetozoa, fungi, and lichens,
from collections made by Docters van Leeuwen (1936)
and by Boedijn (1940). Summary data in comparable
form of both lower and higher plants are given in Table
4. Given the difficulty of making a thorough collection,
especially of certain groups of lower plants, the values
for mycetozoa and fungi are clearly low estimates. Apart
from the higher parts of Rakata (>400 m), where Docters
van Leeuwen was the sole collector of lower plants,
the survey effort in the three islands was of similar
intensity (Boedijn 1940).The inter-island comparisons
are thus of greater interest than the absolute values. It
is nonetheless remarkable how impoverished the lichen
flora was up to 1934. None was collected on the
first post-1883 excursions, nor by Boedijn in 1932-
1934 on the new volcano. The species that were found
in this period were all epiphytic on higher plants (Boedijn
1940).
There is a consistent ranking in the number of species
in each taxonomic group in Table 4, with Rakata having
the largest flora, followed by Sertung and then R.
Kecil: however. the numbers are not proportional to
island area. Sertung generally had fewer species up to
1934than might be predicted on the basis of area alone,
but in contrast, also held a high number of species of
fungi not found on the other islands. This pattern is
not repeated in the higher plants. of which Rakata had
far more "unique" species up to 1934 than Sertung and
R. Kecil. By 1983, the 13-km2area of Sertung might
be expected to have collected a higher cumulative vascular
plant species total in comparison to R. Kecil's 3
km2;the numbers were 238-246 and 202-203 species,
respectively (Table 4). The variations in survey thoroughness
and timing may be partially responsible for
this, although the similarproportions of the 1982-1 983
floras of these two islands (Table 3) suggests that this
relationship is a genuine feature.
Larger islands provide not only more opportunity
for establishment but also a generally more diversified
nature (Boedijn 1940). R. Kecil and Sertung are both
long, thin, low islands, with a very similar range of
habitats. The major apparent differences beween them
are (1) the lagoons once found on Sertung, which enabled
only one or two additional species to colonize
(e.g.. Lumnitzera racetnosa and Halophila ovalis),and
(2) in the proportions of particular coastal habitats. In
contrast, Rakata is a rounded island, with a large expanse
of upland. providing habitats of environmental
characteristics very different from those of the other
islands. Many species have been recorded only in these
higher parts of Rakata, e.g., Acriopsis javanica, Agrostophj-llumbicuspidatum,
Crepidomanes bipunctatum,
C. humilis, and Schefflerapolybotrya (see also Docters
van Leeuwen 1936). The family that fits this pattern
most clearly is the Orchidaceae: of 51 species known
from the group, 33 have been found only on Rakata
(Appendices I and 11).These observations support the
view that the occurrence of major habitat types is of
overriding importance in determining the number of
species on these islands (cf. Buckley 1982, 1985, Bush
1986b). The low numbers of lichen species recorded
from Sertung and R. Kecil and the low numbers of
fungi on the latter cannot be explained on the basis of
constraints of area. Habitat differences, or environmental
history (such as volcanic emissions from Anak
Krakatau) may be the key, but data are insufficient to
resolve this question.
In general. the inter-island patterns shown by the
cumulative totals for 1883-1983 are similar to the
1883-1934 figures (Table 4). There have, however, been
a disproportionately large number of new species of
Pteridophyta found in the last 50 yr as compared to
the first, particularly so in the case of R. Kecil, although
the actual numbers involved with Rakata are much
larger. The cumulative curve for the whole group of
islands remains steep (Fig. 17A). with the gap between
spermatophyte and pteridophyte totals continuing to
increase. albeit at a lesser rate. The most similar pattern
to this is shown by the Rakata data (compare Figs.
17A-D), with the 1983 cumulative total representing
87% of the total for the group of islands. compared to
52 and 44% for Sertung and R. Kecil, respectively. The
latter two islands did not receive a proper survey in
1951, nor a 1979 data point, and thus have a flatter
curve between 1934 and 1982 than Rakata. Nonetheless,
the rate of increase in the flora is clearly less than
for Rakata in the post- 1934 period (cf. Table 3). These
figures are paralleled by the pattern in species found
on only one of the islands, for both the 1883-1 934 and
1883-1 983 collations (Table 4). A substantial proportion
of the Rakata flora has not been found on Sertung
or R. Kecil. amounting to 45% (of which half were
ferns). compared to totals of 17 and 8% for the equivalent
portions of the Sertung and R. Kecil floras. This
pattern is argued to be substantially based upon "habitat."
rather than "area."
h'oncumulative species totals
Rakata.-Although the comparability of the various
surveys is not directly quantifiable, the broad pattern
of the change in species number present on Rakata
remains of interest. The precise form varies. depending
on the initial assumptions made (compare Table 3.
Figs. 17. 18. 19). but the underlying pattern is one of
a continually increasing flora in which the gap between
cumulative and noncumulative totals has continued to
rise over the last 50 yr. We present two means of estimating
noncumulative totals for Rakata: (I)the num-
92 R. J. WHITTAKER ET AL. Ecological Monographs 

Vol. 59. No. 2 

TABLE3. Higher plant species numbers of the Krakatau islands. Nrec is the number of species recorded in each survey as
given in Appendices I and 11. The numbers in parentheses are species introduced to the islands by people. A range in the
data is indicated by two figures separated by a hyphen; this allows for uncertain taxonomy.
Pteridophyta Spermatophyta  P + S total
Date* Nrec Cumulative Nrec Cumulative Nrec Cumulative
a. Rakata 

1886 

1897 

1908 

1920 

1922 

1924 

1929 

1932 

1934 

1951 

1979 

1982 

1983 

29 + 32 

29 to 34 

79 to 83 

b. Sertung
c. Rakata Kecil 

1897 5 5 

1908 3 6 

1929 10-16 12-1 7 

1932 15-18 18 

1951 3 19 

d. Anak Krakatau 

1934 0 0 17-20 

1949 I 1 11-12 

e. Cumulative totals for Rakata. Sertung. and R. Kecil combined
Date Pteridophyta Spermatophyta  Total Total - (I)?
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 93
TABLE3. Continued
Date Pteridophyta Spermatophyta Total Total (I)?-
1934 6 1 264-265 (28) 325-326 297-298
1951 72-74 280-283 (32) 352-357 320-325
1979 89-92 328-339 (32) 4171131 385-399
1982 99-105 334-360 (32) 433-465 401-433
1983 104-1 10 35 1-378 (32) 4551188 4231156
* Combinations of different surveys are given as: '29 + 32' = 1929 and 1932, '29 to 34' = 1929, 1932 and 1934.
t Total - (I) is total higher plants minus introduced species. In addition to the species found on the main islands, 8 or 9
species have been found only on Anak Krakatau, 3 or 4 of these as seedlings in 1932-1934, 1 in 1979, 1 in 1982 and 3 in
1983(Appendix 11).Two of the species in the 'I' category have subsequently been found on a second island without necessarily
having been introduced by people.
ber of species actually recorded as present in a partic- from the 40-42 species known from 1920. Thus both
ular survey or combination of surveys (=Nrec); (2) the pteridophyte and spermatophyte components have
number of species present on the assumption of min- continued to increase through the study penod (Fig.
imum turnover, i.e.. Nrec plus species found both pre- 18).
viously and since (=Nmt). The Nrec model (Fig. 18) The noncumulative total may also be estimated ussmooths
the data, suggesting a gradual increase in the ing Nmt (Fig. 19A).By this "minimum turnover" model
size of the flora, rather than the fluctuations indicated it is assumed that species simply went unrecorded rathby
the raw survey data (Table 3. Fig. 16). The 1979 er than going extinct and re-invading (above). By this
data revealed apparent stabilization in the number of model, it is apparent that the noncumulative total is
pteridophyte species present on Rakata since 1920; underestimated in the 1920s by Nrec (see Fig. 19B).
however, 64-7 1species of pteridophytes are now known These analyses suggest that it would be unwise to atfor
the 1979-1983 period, indicating a clear increase tempt to make a precise estimate of the rate of increase
TABLE4. Cumulative species totals. Two figures separated by a dash indicate a range due to uncertain taxonomy. Numbers
in parentheses indicate species introduced by people. R + S + K indicates combined data for all three islands. Data are
from Appendix I (higher plants), and Boedijn 1940 (lower plants).
Rakata Sertung R. Kecil R + S + K
Area 17 km2 13 km2 3 km2
Subject Altitude 735-8 13 m 182 m 147 m
.A. For period 1883 to 1934 inclusive
HIGHERPLANTS
Pteridophyta
Spermatophyta
Total
Species recorded
on that island only
Pteridophyta
Spermatophyta
Total
Mycetozoa
Fungi
L~chens
Total
Species recorded
on that island only
B. For period 1883 to 1983 inclusive
HIGHERPLANTS
Pteridophyta
Spermatophyta
Total
Species recorded
on that island only
Pteridophyta
Spermatophyta
Total
R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59, No. 2
@ RAKATA ,SERTUNG & R. KEClL COMBINED @ RAKATA
1
500 7
1 

P PTERIDOPHYTA
S SPERMA TOPHYTA
Ip+s
..............
..........
......... pSURVEY POINTS
@ SERTUNG @ R. KEClL
300 -
P+SV)

II!
$
0
200 - 8! 200
u 

/
-iT
0
-/ 0
u
W - __-- iTm W
5 m
f -z C 

z 

100 - 100 .
P - ,
.......................... . P
.................... 

0
,....I
I
, I U I f , ............
'i 0 I I
1883 1903 1923 1943 1963 1983
I
I I
I
1883 1903 1923 1943 1963 1983
F I G 171-11 Cumulative species totals over time for Pteridophyta (PI,Spermatophyta (9,and all higher plants (P+ S)
for the three older Krakatau Islands. Data from Table 3; where a range is given in Table 3, only the minimum value has
been plotted.
June 1989 RECOLONIZATIONAND SUCCESSION ON KRAKATAU
in noncumulative totals on Rakata on the basis of the
raw survey data. Clearly the minimum-turnover calculations
(Nmt) are dependent on thorough surveys at
the end of the study period, and hence the later data
points are not reliable; 1951 was a poor sample, and
1979 was not independent of the 1982-1983 data;
therefore they both underrepresent the flora of the last
50 yr. Apart from the early portion of this curve, the
main interest in calculating the minimum-turnover
values is in the pattern of persistence of the early assemblages,
discussed below (see Rate of Loss of Early
Rakata Assemblages).
R. Kecil and Sertung. -Despite an intensive survey
effort, in which some parts were explored for the first
time, the 1982-1983 species total for Sertung is no
greater than the 1920 total (Fig. 18B). In the case of
R. Kecil, the number of spermatophytes has fallen dramatically
compared to the 1929-1 932 total (Fig. 18C).
In spite of a near doubling in the number of pteridophytes
(in line with the cumulative pattern), the combined
total for all higher plants on R. Kecil also falls
compared to 1929-1932. This pattern can be seen
equally well in comparisons of single survey points in
Table 3. A rise in extinction rate due simply to successionally
driven habitat loss could not provide an adequate
explanation for this pattern given that no such
fall has occurred on Rakata, and given that most of R.
Kecil had experienced forest canopy closure by the
time Docters van Leeuwen (1936) commenced his study
there. Species numbers on R. Kecil are remarkably low,
with Spermatophyta totals comparable to those on Anak
Krakatau, with its relatively tiny vegetated area (Table
3c, d). Although Anak Krakatau has undoubtedly been
more thoroughly surveyed, this pattern clearly is evidence
of an impoverished flora on the larger island.
Both islands have been subject to disruption, Anak
Krakatau more so than R. Kecil: thus the low species
number on the latter may reflect an impoverishment
of habitats caused by disturbance events so timed (and
of the right magnitude) to enable a few opportunistic
tree species, principally Timonius cotnpressicaulis, to
form the monotonous and species-poor forest described
above (pages 79-80). We interpret these data
as being incompatible with the application of an equilibrium
model, rather the patterns described are the
outcome of the partial destruction of the Sertung and
R. Kecil floras by volcanic action and the subsequent
vegetational response to the disturbances.
Betfileen-island comparisons.-Krakatau provides an
opportunity to examine not only the relationships between
area. habitat, and species number. but also the
extent to which different islands sample different subsets
of the overall species pool. The number of species
found only on one island showed a consistent ranking
from Rakata to R. Kecil in the cumulative data (above.
Table 4). This pattern is repeated within the 1979@
RAKATA
300 1
@ SERTUNG
FIG.18A-C. Speciesrecorded as present in particular survey
periods (Nrec)for Pteridophyta (P),Spermatophyta (S).
and all higher plants (P + S ) for the three older Krakatau
Islands. The ranges indicate uncertain identifications in Appendix
I. Collations are as marked above the horizontal axis
of each graph (e.g., 5th data point on [A]is for 1929-1934).
Data derived from Table 3.
R. J. WHITT'AKER ET AL. Ecological Monographs
......................... 

(........' y SURVEY POINTS 

1 CUMULATIVE A
FIG. 19. (A) Species present on Rakata for given survey
dates. calculated on the assumption of minimum turnover
(Nmt), i.e., cumulative totals minus species losses that were
permanent within the study period (i.e., up to 1979-1983).
Data from Appendix I. (B) Rakata flora build-up according
to three differing models, for all higher plants. From Figs.
17B. 18A. and 19A. The difference between curves A and B.
and A and C, is equal to the species extinction curve for each
method of calculation. Comparison of B and C suggest that
each method underestimates the number of species present
on the island at some points in time (see The Developing
Floras of Krakatau: Noncumulative Species Totals: Rakata.
pages 9 1-95).
Vol. 59, No. 2
1983 survey data, both for simple totals and as proportions
of each island's flora (Table 5). Relatively few
species occur in two-island combinations, especially
between Sertung and R. Kecil, whereas >50°/o of the
Sertung and R. Kecil floras are shared by all three
islands. Examination of Appendix I and Tables 4 and
5 indicates a core of shared species, presumably related
to the possession of common habitat types. with Rakata
effectively sampling a separate pool of upland taxa.
Similar proportions of the 1883-1 934 floras of each
island have been re-recorded in the 1979-1 983 period
(Table 6). ranging from 54% for Rakata to 49% for R.
Kecil: however. the early pteridophyte floras have persisted
better on R. Kecil than on the other two islands.
This may be hypothesized to be due to the reprieve of
early light-demanding pteridophytes on R. Kecil due
to recent volcanic disturbance and the consequent interruption
of successional processes (see Appendix I).
Particularly in the case of R. Kecil, however, the numbers
involved are small and the apparently high 'persistence'
of this flora could be a reflection of a low
initial sample. The pattern displayed by the spermatophyte
flora is of more interest, and displays an improving
trend of persistence from R. Kecil to Sertung
to Rakata, which is supportive of the disturbance
explanation outlined above. and of a variable response
rate to environmental change by the pteridophyte and
spermatophyte floras (seediscussion of dispersal mechanisms,
below).
Rate of loss of early Rakata assemblages
Of the 24 species identified from Rakata in 1886,
50°/owerefound on the island in the 1979-1983 surveys
(Table 7). Most of the species loss is accounted for by
pteridophytes. only 3 of the 11 species being found in
1979-1983. Ofthe 108 species ofthe 1908assemblage,
59% are still present on Rakata, with the pteridophytes
again accounting for the greatest proportionate loss,
only 40% of their number remaining. Table 8 provides
a summary of the fate of each Rakata assemblage, and
the overall shapes of the decay curves are given in Fig.
20. The percentage of each pteridophyte assemblage
that remained in the 1979-1983 period steadily increases
up to the 1922 datum, with a particularly clear
increase from the 41%for the 1908 assemblage, to 61%
for the 1920 assemblage. This is probably a result of
the colonization by 1920 of forest fern species, a group
whose habitat has remained undisturbed throughout
the remainder of the study period. The high persistence
of the early spermatophytes. especially of the 1897
assemblage. may be habitat-controlled in that a speciesstable
beach community constituted a large part of the
earliest assemblages (Table 8 and below). The persistence
of each of the 1920s spermatophyte assemblages
i,svery similar. with a marked increase in the figure for
the 1932 and 1951 assemblages. Interestingly. if these
data are converted to an overall rate of species lost per
year, the highest rate of loss is from the 1929 assem-
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 97
blage, declining thereafter (Table 8). Fig. 20 also suggests
a continual increase in the steepness of the decay
curves for each assemblage up to the 1929 starting
point, while the less thorough survey of 1951 has a
shallower slope. This pattern probably relates to the
completion of forest canopy closure in the late 1920s.
and thus to an increase in successional "turnover."
Habztat and spec~es-turnover
From data presented in Treub (1888)and Ernst (1908)
it is possible to follow the fate of the beach and inland
components of the early assemblages of Rakata (Table
7). It is evident that the 1886. 1897, and 1908 assemblages
show a greater loss from the inland flora than
from the beach flora (Table 7). These data indicate that
the earliest beach floras have persisted well and have
been little affected by "turnover." The floras of the
interior have shown a much greater rate of loss, with
a disproportionately high number of these being of the
pioneering species of pteridophytes. Two hypotheses
may be constructed: first. that there may have been
some under-sampling of the interior compared to the
beaches in 1979-1983. leading to artefactual differences
in extinction rates; and second. that the differing
natures of successional processes in the "inland" and
"coastal" habitats have resulted in more species turnover
in the inland flora. Neither hypothesis can be
rejected on the available evidence. Coastal floras may
have been more thoroughly surveyed. as it is difficult
to investigate the interior as systematically, but the
nature of the species lost also fits with a habitat-determined
explanation, in which much of the turnover
inland has been successional in nature, as fern and grass
savanna gave way to shrubland and forest. while the
coastal vegetation communities have changed little (Fig.
15). This pattern is clearest in the 1886 and 1897 assemblages
in which. respectively, 80 and 84% of the
beach assemblages were found in 1979-1983, compared
to 29 and 47% of the inland assemblages. The
data for 1908 indicate a weakening of the pattern, with
TABLE5. Species found on Rakata (R).Sertung (S). and Rakata
Kecil (K) in the period 1979-1983. P = Pteridophyta,
S = Spermatophyta. The percentage calculations are for
each cell as a proportion of the total species number for
each island (R. S. or K) for the indicated period. Data
derived from Appendix I.
O/o % %
of of of
Species present on P S Total R S K
R on11 36 93 129 49
S onl) 6 25 31 22
K onlk 3 4 7 6
R and S (but not K) 3 27 30 11 21
R a n d K ( b u t n o t S ) 8 21 29 11 25
Sand K (but not R) 3 3 6 5 5
R and S and K 17 59 76 29 53 64
Overall total 76 232 308
TABLE6. Fates of the species found within the first 50 Sr on
Rakata. Sertung and R. Kecil. i.e.. of the cumulative assemblage
of the period shown. PI. S1, and Totl are the
numbers of species of pteridophytes. spermatophytes. and
their sum. respectivel~,.P2, S2. and Tot2 are the percentage
ofeach ofthese floras found within the period 1979-1983.*
PI P2 S1 S2 Totl Tot2
Rakata 1886-1934 58 53% 194 55% 252 54%
Sertung 1897-1934 25 52% 148 52% 173 52%
R. Kecil 1897-1932 18 67% 118 46% 136 49%
* The introduced species (I in Appendix I) have been excluded
from these calculations. as they show a disproportionately
high rate of loss (as shown in Table 3).
an increased susceptibility of the beach flora and a
continued improvement in the persistence of the inland
flora. Overall, these data support the view that the
characteristic strand-line taxa of these islands established
early and have been little affected by "turnover"
sensu MacArthur and Wilson (1967). The data presented
by Docters van Leeuwen (1936:77) indicate that
the size of the beach flora for all three islands combined
increased from 68 in 1920 to only 75 in 1934. despite
the fairly comprehensive surveys of the period, indicating
a divergence from the pattern for the flora as a
whole, which has continued to rise throughout.
.Means of arr~valof the Krakataujloras
Using the characteristics given by Ridley (1930),
Docters van Leeuwen (1936). and Backer and Backhuizen
van den Brink (1968). data for those plants
recorded on the islands (excluding Anak Krakatau) between
1979 and 1983 have been added to the data for
dispersal mechanism given by Docters van Leeuwen
(1936:240) (Fig. 21). The cumulative totals for spermatophytes
in each dispersal category for the entire
1883-1983 period are wind = 99. sea = 103. animal
= 123. humans = 32 species (compare with Fig. 21).
Clearly it is difficult to prove that a given species has
arrived by any one particular dispersal agent, but the
general pattern is probably fairly reliable. In a few cases.
it was not possible to decide between two alternative
mechanisms and a score of 0.5 was then assigned to
both categories.
The wind-dispersed component.-The first colonizers
recorded in the interior of Krakatau after 1883 were
principally blue-green algae and pteridophytes, with
only a few flowering plants. The large production and
small size of cyanophyte and pteridophyte propagules
pre-dispose these groups to long-distance wind dispersal.
In the pioneering species. these features are
combined with the ability to tolerate the extreme climatic
and edaphic conditions on the islands. The initial
vegetation cover of the interior was dominated (in terms
of both cover and species number) by pteridophytes,
a situation that had changed by 1897. The early windborne
flora changed the nature of the soil and microclimate,
thereby improving the conditions for other
98 R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59, No. 2
TABLE7. Fates of early floral assemblages of Rakata, assuming minimum turnover. Each dated assemblage is made up of
the cumulative species total to the year given. minus those species not found in either that or any subsequent survey.*
a. The 1886 assemblage
Census date
1979- Yo
Habitat? Order 1886 1908 1920 1929 1951 1983 persisting*
Beach Pteridophyta 1 1 1 1 0 0 

Beach Spermatophyta 9 9 9 9 8 8 

Total Beach = 80%
Inland Pteridophyta 10 9 8 6 3 3
Inland Spermatophyta 4 4 4 3 1 1
Total Inland = 29% 

Combined total 24 23 22 19 12 12 = 50% 

b. The 1897 assemblage
1979- YO
Habitatt 1897 1908 1920 1929 1932 1951 1983 persisting*
Beach Pteridophyta 7 2 2 2 2 1 1 

Beach Spermatophyta 2 i 23 23 23 22 21 20 

Total Beach = 84%
Inland Pteridophyta 11 11 10 8 7 3 3
Inland Spermatophyta 19 19 17 15 13 11 11
Total Inland = 47%
Combined total 55 55 52 48 44 36 35 = 64%
c. The 1908 assemblage
1979- YO
Habitat? 1908 1920 1929 1932 1951 1983 persisting*
Beach Pteridophyta 2 2 2 2 1 1 

Beach Spermatophyta 38 36 34 32 29 27 

Total Beach = 70%
Inland Pteridophyta 15 14 12 11 7 6
Inland Spermatophyta 53 49 46 40 32 30
Total Inland = 53%
Combined total 108 101 94 85 69 64 = 59%
d. The 1920 assemblage
Species group 1920 1922 1924 1929 1932 1951 1979-1983
All Ptendophyta
All Spermatophyta
Combined total
Introductions
Total minus Introductions
e. The 1922 assemblage
1922 1924 1929
All Pteridophyta 48 47 47
All Spermatophyta 145 141 137
Combined total 193 188 184
Total minus Introductions 184 182 178
* As an illustration, in part c. 8 (inland) species of the "1908 assemblage" were not collected in 1905-1908, but were found
both earlier and later, and have therefore been included in the starting figure of 108 species. Subsequent cells to the nght give
the number of species remaining on the island on the assumption of minimum turnover (i.e.. extinctions are counted only if
permanent up to 1979-1 983 inclusive).
t The breakdown into beach and inland components follows Ernst (1908) and Docters van Leeuwen (1936) and reflects the
habitat In which each species was first found. Species of uncertain taxonomy have not been included unless known to be the
only member of the genus found. Data from Appendix 1.
*The percentage figures are the proportion of the starting total found in 1979-1983.
nonxerophytes. We cannot necessarily assume that the prior to their eventual colonization yet failed to estabwind-borne
seed/spore bank has remained constant lish due to unsuitable environmental conditions. Elevthrough
the period since the 1883eruption. but doubt- en of the initial 16 anemochorous species were pteriless
propagules of many species arrived several times dophytes (Fig. 2 1). but as the succession proceeded the
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
early dominance of this group declined, and in 1908
only 12 of 32 anemochorous species were pteridophytes.
The proportion of Pteridophyta fell from 42%
of the total vascular plant flora in 1886 to 10%in 1908.
During this period, a Ficus-,Macaranga forest had
begun to develop on the lower slopes of Rakata and
the upper areas had a cover of Saccharurn grassland.
As the forest of the low to middle altitudes developed,
new habitats became available for colonization. This
was evidenced by a substantial increase in the number
of pteridophytes, especially forest species, between 1908
and 1920 (Fig. 21). The forest cover was not complete
at this time, resulting in a mixed flora of shade-tolerant
and heliophilous species. Almost all of the pteridophytes
that colonized during this period were epiphytic
or shade/moisture demanding species (e.g., Asplenium
nidus, Davallia denticulata, and Lygodium spp.) (Appendix
I). There then followed an increase in the rate
of arrival of anemochorous flowering plants. as they
colonized this new habitat. There appears to have been
a slight lag (up to 12 yr) between the upturn in pteridophyte
and spermatophytecolonization (Fig. 21).The
number of pteridophytes on the islands continued to
increase over the period 1934-1983, and accounts for
the majority of the net increase in the anemochorous
flora. Approximately 45 species of pteridophytes and
37 anemochorous spermatophytes were recorded for
the first time in 1979-1983. with only 50% ofthe 1883-
1934 anemochorous spermatophytes persisting (Table
9). There has been a slightly higher proportion of pteridophytes
lost of the 1883-1 934 Rakata flora than of
the equivalent R. Kecil flora (Table 6), and the winddispersed
spermatophytes found only on Rakata in
1883-1934 also show a poor degree of persistence (TaTABLE8.
Overall fates of Rakata floral asscmblages. Each
assemblage is made up of the species counted as present in
the respective year (timel) on the assumption of minimum
turnover. P 1.S1, and Tot 1are the numbers of Pteridophyta,
Spermatophyta, and their sum. respectively. P2. S2, and
Tot2 are the percentage of these floras found within the
period 1979-1983 inclusive (time2).
Annual 

Assem- loss 

blage PI P2 S1 S2 Totl Tot2 rate* 

*The proportion of Totl lost between timel and time2
expressed as an annual rate.
t The Introductions noted in Appendix I have been excluded
from these calculations. as they show a disproportionately
high rate of loss (see Table 7).
1883 1903 1923 1943 1963 1983
FIG.20. Decay of Rakata floral assemblages (all higher
plants) calculated on the assumption of minimum turnover.
The dates indicate the starting point of each assemblage (see
The Developing Floras of Krakatau: Rate of Loss of Early
Rakata assemblages, page 96). Data from Appendix I.
ble 9). As those species lost were very often the most
strongly heliophilous members of the early savanna
vegetation (Appendix I), these results support the interpretation
of turnover as in large part successional
in nature.
The sea-dispersed component.-The early importance
of the thalassochorous plants reached a peak of
>50% of the total flora 25 yr after the eruption. Since
then the net curve for sea-dispersed taxa has levelled
off. and over the last 50 yr has fallen slightly. This is
in part because relatively few new sea-dispersed species
have been recorded in 1979-1 983, the figures for sea-.
animal-, and wind-dispersed components being 16,39.
and 37 respectively. Small losses from the 1886, 1897,
and 1908 assemblages of Rakata suggest that the early
beach assemblages (broadly equivalent to the sea-dispersed
species) formed a species-stable community. In
contrast. only 53% of the 1883-1934 sea-dispersed flora
(ofthethree islands) wasrecordedin 1979-1983, which
is almost as low as for the wind-dispersed flora (50%),
and considerably lower than for the animal-dispersed
flora (71%) (data in Table 9). This indicates a considerable
increase in turnover among sea-dispersed species
colonizing in the 1920s and 1930s.
Several factors may be important in explaining this
apparent contradiction. First. there are few accreting
beach environments on Krakatau: coastal erosion has
been the dominant process throughout the post- 1883
period. Thus certain coastal habitats have been noncontinuous
or restricted in their extent, and the loss of
some sea-dispersed species can be directly attributed
to the disappearance of their habitat (e.g.. the brackish
lake on Sertung). These species include: Centella asiatica,
Halophila ovalis, Lumnitzera racemosa, and Xylocarpus
granatum. Species on the spit of Sertung may
have been lost because of either coastal change or erup-
100 R. J. WHITTAKER ET AL Ecological Monographs
'1583 '9Q3 1923 '943 1963 '983
FIG.21. Means of dispersal of the Krakatau flora: all higher
plants and for all islands (combined) except Anak Krakatau.
Data from Docters van Leeuwen (1936) for all points except
1979-1 983. data from Appendix I, with dispersal characteristics
culled from Ridley (1930). Docters van Leeuwen (1936).
and Backer and Bakhuizen van den Brink (1968). The totals
are for collations, rather than only the dates indicated.
WINDIS and WINDIP = wind-dispersed Spermatophyta and
Pteridophyta. respectively.
tions: of 15 sea-dispersed species recorded only on Sertung
in the 1883-1934 period. only 1was found within
the group in 1979-1983. Some of the other apparent
losses leading to the decline in this component of the
flora were of species that never really colonized successfully.being
collected (largelyin the 1920sand 1930s)
in juvenile form from the strand-line. An example of
this "over-sampling" is the mangrove Avicennia alba,
recorded on Rakata: the largest specimen had only 6-
10 leaves (Docters van Leeuwen 1936:413). and the
island clearly lacks the necessary habitat for successful
mangrove establishment. Other examples of such juveniles
or "ephemerals" include: .4eschynomene inVol.
59, No. 2
dica, Crotolaria striata, ~tfesserschmidia argentea,
Opuntia elatior, and Spondias mang~fera.It would be
difficult to be consistent in removing such ephemerals
frbm the data, we therefore retained them for the calculations.
These factors provide a partial explanation
for the apparent increase in turnover in the 1920s (see
Rate of Loss of Early Rakata Assemblages. above).
We have few data on the frequency of particular
species in the strand-line flora: however. a crude indication
of the commonness of groups of species can
be derived from the number of islands on which they
have been found through time (Appendix I). Table 9
shows the dispersal mechanism compared to the island
combinations on which each species was found
in 1883-1 934. Speciesfound on only one island display
the poorest persistence, and those occurring on all three
islands the best persistence. This pattern is shown in
each of the dispersal categories taken separately, but is
strongest in the sea-dispersed category, in which 42 of
the 47 species persisting in 1979-1983 were found on
all three islands in 1883-1934 (Table 9). This corroborates
the suggestion that most losses have been of
species of restricted distributions (e.g., many of the
"ephemerals") and few. if any, of the characteristic
species of the early strand flora have been lost (above).
The animal-dispersed component. -Six zoochorous
taxa. probably all bird-sown, were recorded in 1897
(Docters van Leeuwen 1936). The zoochorous component
has increased steadily to a total of -99 in 1983,
showing the highest rate of increase from 1934 totals
of the four spermatophyte components (Fig. 21). The
continued increase in this component may be related
to a positive feedback in which more fruiting trees
attract greater numbers of visiting birds and bats. These
visitors drop more seeds, introducing more zoochorous
species (Thornton 1984). There are now four species
of frugivorous bats and 11 species of frugivorous birds
on the islands (Thornton 1986. Tidemann and Zann
TABLE9. Fates of 1883-1934 floras by dispersal mechanism. The combined 1883-1934 floras of Rakata, Sertung. and R.
Kecil (R. S, and K respectively) are broken down into island vs. dispersal mechanism combinations.*
Persisting in 1979-1983 Absent in 1979-1983
Island Wind Sea Animal Row totals Wind Sea Animal Row totals
RSK 12.5 42 20.5 75 6 6.5 3.5 16
Col. tots 32.5 46.5 58 137 32.5 41 23.5 97
* To be counted as "persisting" in 1979-1983 a species had to be recorded on any combination of R, S, and K, e.g., ten
animal-dispersed species were found on both R and S (but not K) in the 1883-1934 period and on one or more of the three
islands in 1979-1983. The numbers of species of 1883-1934 which were not found in 1979-1983 are given in the right half
of the table, as 'Absent' (e.g.. for the same case = 1). In a few cases it was not possible to decide between two possible
mechanisms and a value of 0.5 was entered.
101June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
1986. Thornton et al. 1988). Of the main inland forest
types of Krakatau (Dysoxylum,Ficus, Areonauclea and
Tzmon~usforests), all except the h'eonauclea forest are
dominated by zoochorous species. The zoochorous
component shows both a comparable number of new
species to the anemochorous component (above) and
a significantly lower proportion of losses from the 1883-
1934 flora (Table 9). The implications of these findings
are discussed below.
Introducedflora. -In Appendix I. 32 species are recorded
as having been introduced to the islands by
humans. Of these. only 3 (i.e., only 9%) were found in
the 1979-1 983 period. They have thus sustained a remarkably
high proportion of losses compared with all
other groups of species. It is instructive to consider the
details involving each island.
1. Rakata. -Docters van Leeuwen (1936) lists 17
species of weeds and cultivated plants found around
Handl's cottage in 1919,to which can be added a specimen
of Citrussp. found at ~ 4 0 0 - maltitude, and probably
introduced by visitors. Most of these species were
shaded out shortly after the abandonment of the site.
In 1931, only Gnetum gnemon, J14ang~'$eraindica, .4ntigonon
leptopus, and Boesenbergiapandurata could be
found, and only 3 of the 18 were found in 1979-1 983.
Cocos nuczfera has been planted on all of the islands
at various times. but since there is every reason to
believe it to be a natural colonist as well (Docters van
Leeuwen 1936)it has been excluded from the I category
in Appendix I.
2. Sertung.-Borssum Waalkes (1960) observed a
cottage garden on Sertung in 1951.containing crop and
weed species. 8 of which were new to the island (Table
3).Three other "garden" species had been found earlier
and could have been introduced by earlier temporary
inhabitants (cf. Ernst 1908). All were destroyed as a
result of the 1952eruption of Anak Krakatau, and none
has been found since. Gnetum gnemon, found for the
first time in 1982, may also have been introduced by
humans (above), although it could have been animal
transported. and has also been found on R. Kecil. where
it is far less likely to have been introduced by humans.
3. R. Kecil. -Nine species of weeds were recorded
by Docters van Leeuwen (1936) in the period 1928-
1934 as having been introduced near the Volcanological
Service camp (species marked I in Appendix I).
None has been found since, and it is probable that they
were shaded out very shortly after the post was aban-
doned.
Dispersal mechanisms and-families.-Certain plant
families have been particularly important in shaping
the dispersal curves. For instance, the Orchidaceae accounts
for half of the wind-dispersed spermatophytes
both for 1883-1983. and for 1979-1983 (respectively
52 out of 99 and 35 out of 69). Anemochorous Asclepiadaceae
(13 species). Compositae (17 species) and
Orchidaceae account for 82 of the 99 wind-dispersed
species of 1883-1 983. The wind-dispersed component
is thus mainly made up of nonarboreal species, including
many epiphytes. A third of the 103 sea-dispersed
species of 1883-1983 have been Leguminosae,
but this component of the flora is otherwise fairly diverse
in its composition. Animal-dispersed species
provide the largest group of spermatophytes. with 123
species between 1883 and 1983. The two largest family
groups within this are the Euphorbiaceae. 14 of which
are zoochorous (10 found in 1979-1983), and the Moraceae,
with 22 figs and one other zoochorous species
(19 found in 1979-1 983. Appendix I). Apart from these
families. the animal-dispersed component is also a diverse
group. It will be noted that this group is the most
important in supplying inland forest tree species. Only
the h'eonauclea calycina forests of Rakata are dominated
by a wind-dispersed species. and the trend evident
in these data is a continued diversification of the
inland forest, in which species attractive to birds and
bats (e.g.. Ficus spp., Dysoxylum spp.. etc.) are anticipated
to play an important role.
Thefloras of<4nakKrakatau
The repeated interruptions to the colonization of
Anak Krakatau have resulted in a flora that may well
post-date the 1972 eruption. Disruptions to the processes
of recolonization and vegetation development
may have occurred at many points. and certainly occurred
where major eruptions are noted, e.g., 1932-
1933.1952-1953,1960-1961.1972.1979-1982. Thus
there is no known starting point for the colonization.
and rates of immigration or extinction cannot be calculated.
The present stature of the Casuarina equisetlfolia
forest. its rate of expansion, and the pace of the
1979-1983 increases in the flora (Appendix 11. Table
3d) would be consistent with a post- 1972 revegetation
of the island. The 1979-1 983 surveys recorded a combined
total of 80-83 species of higher plants. a considerable
increase on previous totals. If the diversity of
the flora is an accurate guide, it would suggest that this
period represents the longest period of relatively undisturbed
colonization in the island's history. Not only
has diversity increased, but the composition of the flora
has changed (Appendix 11). Prior to 1979 only one
animal-dispersed species and three wind-dispersed
species had been found, and while the majority of the
cumulative spermatophyte flora (Table 3) are sea-dispersed
species ( n = 45). both wind-dispersed species
( n = 17) and animal-dispersed species ( n = 14) have
increased in importance (the remaining four species
were of unknown dispersal mechanism). In particular
the recent surveys have revealed that a few species
typical of forest habitats elsewhere in the Krakatau
group have begun to colonize. e.g.. Dysoxylum gaudichaudianum,
Ficus spp. and Timonius compressicaulis
(Appendix 11).The low count in 1982 (Table 3d)
is probably attributable to collecting efficiency, but the
minor eruptions of the period cannot be totally disregarded
in their possible effect on this assemblage
(Barker and Richards 1986).
The species found on Anak Krakatau since 1930 are
essentially a subset of those found on the main islands.
Although 8-9 species have been found only on Anak
Krakatau (Appendix 11), 3-4 of these were as seedlings
in 1932-1 933 and can be viewed as ephemerals, with
the remaining five being found within the 1979-1983
period. These figures support the importance of the
local seed source. in particular for species such as Dysoxylum
gaudichaudianum, which has probably been
introduced from within the group by birds. There has
been some debate within island biogeography as to the
extent to which stochastic vs. deterministic rules operate.
and in this context it is interesting to note that
all but one of the 23 species of the 1949-1951 vegetation,
destroyed in the 1952-1953 eruptions (Borssum
Waalkes 1960). have been found subsequently. This
demonstrates a strong deterministic element. presumably
controlled jointly by habitat and dispersal opportunites.
Anak Krakatau remains remarkably poor in
Pteridophyta compared to the other islands, and
whereas. in the cases of some early surveys of R. Kecil
or Sertung, this might be attributed to survey efficiency.
Anak Krakatau has been very thoroughly surveyed.
and its impoverishment must be due to the unfavorable
and disruptive environmental conditions operating.
DISCUSSION:SPECIESBUILD-UPAND THE
COMPONENTSOF TURNOVER
The unique facet of this study has been the analysis
of re-colonization of an insular locality in terms of both
successional ecology and island biogeography. To understand
the factors controlling the pattern of species
turnover and the shape of the colonization curve it is
clearly important to examine the relationships between
community dynamics and floristic dynamics. In 1983,
>50 yr after forest closure, the Krakatau islands remained
characterized by large tracts of species-poor
forest, with a few dominant canopy species, all ofwhich
were typical early sera1 species. Of the lowland forest
communities. those of Rakata were the most mature.
Large areas of Sertung and R. Kecil were covered in
very young forests of Tirnoniuscompressicaulis, an early
stage in recovery from disturbance. Not only were
the vegetation communities and soils of these islands
significantly less mature than those of Rakata. but the
floral data also followed a clearly different pattern, with
Rakata the only island showing continued increase in
species richness.
Perhaps the major factor explaining the inter-island
differences in vegetation and in the curves of species
colonization has been the intermittent disturbances, of
varying severities. which have originated from Anak
Krakatau. On Rakata, there has not been opportunity
for Timonius compressicaulis and Dysoxylum gaudichaudianurn
to invade large tracts of disturbed vege'AKER
ET AL. Ecological Monographs
Vol. 59. No. 2
tation in which the canopy has been broken or destroyed.
In the absence of such disturbance it is unclear
if D. gaudichaudianurn will play a major role in the
forests of the main island. on which its distribution in
1983 was principally near the coast. The explanation
for the relatively low species numbers recorded on Sertung
and R. Kecil in 1982-1 983 is probably linked in
some way to the disturbances. but demands further
field studies. It may be that insufficient time had elapsed
since disturbance-induced losses. or it may be that the
renewed space was occupied so rapidly by the few common
species (especially T. compressicaulis and D. gaudichaudianum),
that they have delayed the colonization
of further species. It is anticipated that in the
absence of major disturbances the dominance of the
canopy of all the islands will become increasingly shared
and that species number will undergo further increases.
On Anak Krakatau, frequent volcanic disturbance.
inhibition of vegetational spread away from the accreting
coastal deposits, and the short distance from
large local seed sources (i.e., the other islands). make
the island a poor analogue for the early post-1883 period.
The major dispersal group has been the sea-dispersed
species and the flora contains a deterministic
corewhich re-colonized following disturbance. The flora
of Anak Krakatau has increased in recent years. its
composition indicating that it has been strongly influenced
by the surrounding islands: recent colonizers include
the commonest tree species of the inland forests
of the other islands.
Analyses of the floral data by habitat and by dispersal
mechanism have revealed an underlying pattern to the
accumulation of species number and species turnover
on the main islands of the group. The relationships
revealed are interesting for several reasons. First, the
coastal environments of the Krakatau islands are clearly
very dynamic, yet the early colonists of the strandline
of Rakata have been subject to a very low proportion
of losses, relative to the flora of the interior.
This trend decreases as the starting point is shifted from
1886. through 1897 to 1908. and later sea-dispersed
species arriving on the group have undergone a relatively
high rate of losses compared to the animal-dispersed
species. This is at least partly because of habitat
losses (due to coastal change rather than autogenic processes).
and oversampling of ephemerals in the 1920s.
Wind-dispersed species appear to have colonized in
two phases. providing the bulk of the primary colonizers
inland, and then after a period of little change
(possibly a reflection of low sampling intensity) a steep
increase in numbers as forest habitats became available.
In both phases. the pteridophytes were faster to
colonize than the anemochorous spermatophytes. Underlying
the curve for anemochorous spermatophytes
has been a relatively high rate of turnover. much of
which has been due to succession (cf.Docters van Leeuwen
1936). The animal-dispersed component was the
slowest to colonize,as would be expected. but has since
103June 1989 RECOLONIZATION AND S1JCCESSION ON KRAKATAU
shown the most consistent pattern of increase in numbers,
suffering a very low rate of losses. Only 29% of
the 1883-1 934 animal-dispersed flora was not found
in 1979-1983, compared to values of -50% for the
other components. Tree species turnover has probably
been unimportant (especially so for animal-dispersed
species), among those species that once established a
viable population, with most real "turnover" being of
the nonarboreal species of the open successional phase.
Large arboreal species have continued to arrive on the
Krakatau islands, although few if any that could be
termed characteristic "primary" forest species. The animal-dispersed
species may nonetheless be viewed as
the most advanced seral group, forming a second
species-stable component (along with the early beach
species).We expect that the majority of further arrivals
of forest tree species on these islands will also be as a
result of the migratory movements of birds and bats
(cf. Thornton 1984).The anthropogenic impact on both
the course of succession and the composition of the
floras of the group remains remarkably slight. Those
species known to have been introduced by humans
have shown a disproportionately high rate of loss. While
those on Sertung were destroyed by eruptions in 1952.
those introduced to Rakata and R. Kecil were shaded
out by the forest.
Floral diversity appears to be only loosely related to
island area, but is a function of ecosystem maturity
and habitat diversity. Much of the pattern within the
curves of species number through time, and in the loss
of species, can be explained with reference to habitatbased
successional changes. Furthermore, the possession
of definable habitat types (e.g.. eroding and
accreting coastal habitats. lowland and submontane
habitats) appears important in determining the size and
composition of the floras of these islands (cf. Whitehead
and Jones 1969. Buckley 1982, 1985). Of the
species found in 1979-1983, 129 were found only on
Rakata (50% of that island's total). the only island with
upland. with the next largest island combination being
Rakata, Sertung, and R. Kecil with 76 species. Only
44 species were found on Sertung and/or R. Kecil but
not on Rakata. The common core of each successive
"new" flora on Anak Krakatau, and the similarities
and differences established among the floras of the main
islands, indicate clear differences in the probabilities
of dispersal and establishment within the overall species
pool. Nevertheless, the composition of the forests of
Rakata shows a gradual variation with altitude (rather
than a boundary at which lowland switches to upland
conditions),illustrating that the "habitat model" is also
a simplification.
In conclusion.the status of Krakatau as both a classic
case study of tropical forest succession (Richards 1952)
and of island biogeography (MacArthur and Wilson
1967) demands review. While a primary successional
framework may be applied to Rakata, the other islands
now include substantial secondary successional elements.
This may be viewed as adding to the value of
this "natural experiment," rather than detracting from
it. The deflection of succession on R. Kecil and Sertung
exemplifies this, showing unpredictable transition
probabilities between different successional paths.
In examining the Krakatau floral data from an island
biogeographical perspective we conclude that the rigorous
data required for a testing of "equilibrium theory"
are impracticable to obtain for islands of this size
and geoecological character. and that there are also
several strong reasons for rejecting the model as being
fundamentally inappropriate. The one island of the
group where an uninterrupted history is available is
Rakata, and its flora has continued to increase in diversity.
Furthermore. far from species turnover being
a random process, it is apparent that: (I)certain groups
ofspecies do not contributeto "turnover." (2)the species
of differing habitats may behave differently in this respect,
and (3) much of the apparent turnover involves
"ephemerals." species lost due to habitat destruction.
and species introduced by humans. Of the rest, much
can be attributed to the processes of vegetation succession
(i.e., it is "successional turnover") and accompanying
environmental and zoogeographical changes.
Neither the pattern of change in the flora, nor that for
some groups of fauna, e.g., the birds and butterflies
(Hoogerwerf 1953, Thornton 1984. Bush 19866)can be
understood without reference to vegetation succession
and the key period in the 1920s when the savanna
vegetation of the interiors gave way to forest. Attempts
to calculate simple immigration and extinction rates
for the total species population are for these reasons
inappropriate to an understanding of the Krakatau data.
Instead. a successional model of island recolonization
is required, involving evaluation of habitat and dispersal
mechanisms.
It is important to emphasize. finally. that the forests
remain of an early seral character. and that the timescale
of seral progression will become increasingly
slower. if for no other reason than the lengthening generation
times of the succeeding canopy species. Despite
the protected status of the islands. the influence of
humans may be expected to become increasingly significant,
indirectly. in removing the source pool of potential
further colonists on Java and Sumatra.
We thank all those who contributed to the two Hull University:
Krakatoa Centenary Expeditions, in particular John
Flenley and Peter Jones for encouragement and comments.
Provisional identifications were carried out at the Herbarium
Bogoriense, Bogor, and where appropriate were checked by
staff of the Reijksherbarium. Leiden and the Royal Botanic
Gardens. Kew. We are indebted to the following for the supply
of information and/or for comments on text: G. A. De Neve,
J. Dransfield. D. Mabberley, D. Newsome, the late C. G. G.
J. van' Steenis. I. W. B. Thornton, and T. C. Whitmore. We
thank J. J. Ewel, E.G. Leigh, Jr., F. E. Putz and W. H.
Schlesinger. for their valuable suggestions in respect to an
earlier version of the manuscript. This work could not have
104 R. J. WHITT'AKER ET AL.  Ecolog~calMonographs
been carried out without the cooperation of L.I.P.I. (the Indonesian
Institute of Sciences). The Herbarium Bogoriense
provided invaluable support and expertise. and we are particularly
indebted to Dr. Kuswata Kartawinata. Gregori Hambali.
Harrq Wiriadinata. Mohammed Amir. and Ramlanto.
Major financial assistance was provided by The National Geographic
Society (U.S.). P.T. BAT Indonesia. The Royal Society.
The British Ecological Society. and The University of
Hull. M. B. Bush thanks the La Trobe 1984 Krakatau Expedition
for funding to participate in that project. and Mark
Walker. Mark Harvey. and Pat Vaughan for being staunch
field allies. We thank the Geography Departments of Hull
University, Birkbeck College and Oxford University, and the
Oxford University Computing Service, for technical assistance
and computing facilities. Figures were drawn by Angela
Newman and Sarah Rhodes.
LITERATURECITED
Baas. P. 1982. Identity ofthe carbonised wood sample from
Krakatau. Pages 181-183 1n J. R. Flenley and K. Richards,
edltors. The Krakatoa Centenary Expedition: final report.
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RECOLONIZATION AND SUCCESSION ON KRAKATAU
APPENDIX I.
THECOMPLETE PLANT LIST FOR RAKATA,
SERTUNG, 1883-1 983.AND R. &CIL
Survey data are combined as shown by the collection periods in Table 2. Upper case R, S, and K indicate species recorded
from Rakata, Sertung, and R. Kecil respectively. Lower case r, s, and k indicate species recorded, but with some ambiguity
in Docters van Leeuwen (1936) as to the year. "?" = uncertain identification. "*" = identification to genus only, when other
species in the same genus have been found. "I" species recorded as having been introduced by humans. ?, *, and I are placed
in the column of the island on which they were recorded. Names in parentheses indicate synonyms, and in square brackets,
either varieties or grouped species. Further taxonomic notes are given at end of table.
Sources:Ernst 1908, Doctersvan Leeuwen 1923, 1929, 1936,Steenis 1938,Boedijn 1940,Borssum Waalkes 1960,Whittaker
and Flenley 1982, Tagawa 1984, Tagawa et al. 1986, Bush et al. 1986a.
P T E R I D O P H Y T X
ANGIOPTERIDXCEAE
Anyzopterzs ewecta (Forst .)Hoffni.
Ar~yzopterzsla~~czfolzatav.X.v.R.
A~~qzopterzspalnazforrnzs (Cav.)C'. C'hr
R R R R R
ASPLENIACEAE
A s p l e r ~ z ? ~ n ~lor~gzsszrnurnBI.
Asple~~zlirnnLacrophyll?irr~Sa..
A sple~~zurnnzdus L.
Asplerizurn th1~7~beryzzKunze
(A,sple7~zurndecorlirr~G.Kuntze)
( A s p l e n z ~ ~ n ~belar~gerzO.K. serisu auct.
- jav.)
-
RS
R
K
R
R
R
R
R s
R
R
K s K
r
K
R
R
R
R
R
R
K
R
RSK
K
BLECHNACEAE
B l e c h ~ ~ u r norzentale L.
Ster~ochlaeriapril~istrzs(Burm.f.)Bcdd.
R
R
R
R
R
R S R R RSK RSK RSK K RSK RSK
C'YATHEAC'EAE
Cyatl~eac o r ~ t a n ~ z ~ ~ a ~ ~ s(Hook.)C'opcl
(Alsophzla gla~rcaJ.Sm.)
Cyathea sp.
G f ~ ~ u szqr~ota
R K R K R K R
CRYPTOGRA11\1AC E X E
CJr~ychzurr~I Z ~ Z ~ I L ~ O ~ ? L T RC C't~r R R R
DALrALLIACEAE
Davallza der~tzculata(Burm.f.)lIett.
Davallza solzda (Forst.)Sw.
Davallza trzcl~ornar~zozdesBI.
(Dauallza dzsserta J.Sm.)
Hurrlata heterophylla (Sm.)Dcsv.
Hurnata repens (L.f.)Dicls
Scyphularza perztaphylla F'cc
R S R
K
R
R
R s k
R
RSK
K
R R
R
R
R
R
R
K
R
R
RSK
SK
R
K
DENsSTAEDTIXCEAE
Lzridsaea repens (Barry) Thwaites
(Lzridsaea pectzr~ataBI.)
Pter-zdzorn ari~izlzriurn(L.) K u h n
( Eupterzs ar~?~zlzr~aNewm.)
hfzcrolepza spelur~cae(L.)lloorc
Sphenornerzs chz~?e~?szs(L.)hIaxon
( S t e n o l a n ~ achlisa~~urnC'hun.)
S
R
K
R
R
R
K
R
R
DRYOPTERIDACEAE
Dzplazz~irnpolypodzozdes BI.
Pleocr~ernza(.on]?~gata(BI.)Pr.
K K
R
K
R K
'!
R S
108 R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59. No. 2
APPENDIX I. Continued
P l e n r ~ ~ e n ~ z acf. hernztelzzforn~zs(Racib)Holtt R RSK
Pli,oc~?en~zuzrregula7-zg (Pr.) Holtt . R K
(Arcypterzs zrreqularzg (Pr.)Holtt.)
Str~~oserrlzaawrzta (Sw.)Pr.
T e c t a ~ z adzggecta (Forst.) Lellirigcr
(Ctrriztzs dzsserta (Forst.)Ctiing)
Tectarza herpetocualos Holtt. R K
Tertarza n~i,lurioca~~lu.C'opel. R R R R R R R K
(ilspzdzarn rnelariocaulo~~B1.)
Tectarzu gzzfolza
( Tertarza polymorpha \Vall.Copcl.)
Tf,rtarza sn.
EQIISETAC'EAE
Eqazsf~til7rr dehzle Koxt) R R R K R
c:RAhIlIITIDAC'EXE
Ctrriopterzs alata (BI.)Holtt. R R K
(Prosnptza alata Christ.)
Ctrnoptf'rzs blech~?ozdes(Grev.)LZ'agncr -
Grether
(Ctrrioptorzs r r i o ~ ~ l i o r ~ ~( C ~ p r l . ) A d c l b c r t )
(Polypodzurn rno7~1torizC'oprl.)
Grurnrnztz,s rvervzcorria (v.X.v.R.)Adcli~crt
HYLlENOPHYLLACEAE
C'rrpzdon~u~?r,,shzpurictatarri (Pi~ir.)C'nprl R R R
(Trzchr~mar~egb z p l i ~ ~ r t a t a n ~Poir.)
Rppdzellr~ILILTILZ~ZS(Fasd.) Pic. Ser. R R R R R
( C7-epzdopterzg ILILTIIZ~ZS(Forst . ) C ~ ~ r l . )
( Trzcliori~a~?f~,shurnzle Forst .)
H y n ~ i ~ ~ ? o p h y l l u n ~cf. jai1unzr7~n~
LYC'OP0DI.AC"AE
Lyropodrarii curz~~atrlnLDrsv.
Lyropodl~~rrirernaurr~L. R R R R K R R
Lycopodzurr~riurnn~ularzfolzurn
Lycopodrurri ~ q a u r ~ o ~ ~ ~ ~ t rForst. R R R
OLEANI3RXCEAE
Nephrolrpzs acunaz7auta (Houtt .)Kuhn R
.\'ephrolrpzg bzsrrrata (Su,.)Schntt R R K RSK R S R R RSK RSK R K SK RSK
(Nephrolepzs eraltata (S~v.)Sctiott)
~Vrphrolrpzs hzrs1~t7~ln(Forst.)Pr. R
POLYPODIXC'EXE
A g l a o ~ r ~ o r p h aheracli,a (Kzc)C'oprl. K R R K
(Polypodzurn hf.7-arlel~n~Kze)
Belzrzsza rallzfolza (C'hr.)Coprl.) R K R R R
( l l y n ~ t r ~ o l r p z scallzfolzu Ctir.)
Beltlzsza r e i ~ o l l ~ t a(BI.)C'opel. R K R R R R
( H y r i ~ o r ~ o l o p z ~7.i ~ ~ o l a t aBI.)
Brltlzsza 5p. *
( I T ~ P ~ Z ~ L I L St7'2~0blL~( H o u ~ ~.)C'<>pFl. R K R
Dr?jrnoglossurr~pzlosrllozdes (L.)Pr. K R R R R K SK
D r l j ~ ~ a r z r ~qaf,rrzfolza (L.)J.Sm. R R R S R K R S K R 5 K RS R RSK RSK
1 + Dry??arza sparczsora (Drsv.)hloorc]
Lrcanopfi,rzs 9zr~aoga(LZ'all. r u Hookrr)Copcl R R S
(Phyrirutodi,~sznuoga (\Vall.),J.S111.)
( P o l y p o d z ~ ~ n ~zriuosurr~\fill.)
109June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
APPENDIX I. Cont~nued.
-
1886 1897 1908 1920 1922 1924 1929 1932 1934 1951 1979 1982 1983
Len~rnaphyll1~7rr R R R R R R R K Rar redens (Bl.)Donk
(M.'eatherhya arrf.de??s C'opel.)
(Polypodzurn a c c e d e r ~ ~BI.)
L e p z ~ o r u ~ (BI.)Holtt.lor~gzfolz?~s
(Paragrurnrna lonqzfolza (B1.) XIoorc)
Lorogramma uoer~za(BI.) Presl. K
A2fzc~-o,sorurnLzng?rzformr (hlr,tt.) C'opt,l. R
hfzcrosorun~p i ~ r i c t a t ? ~ n ~ - R R S R K R i k R s k RSK(L.)C'npel. seiisli
- allct. jav. 

(Polypodz~~rn Swcct .)
p l ~ n r t a t l ~ r n
.bTzcro~orurnr u h z d ? ~ n ~(Klinzr) C O ~ C I . R R
(Phyrnatode,\ lo~~gzsszrna(BI.)J.Sni.)
(Polypr>dzurnL O T L ~ Z S S Z T ~ L I L ~ ~ L BI.)
(Plrope1tz.s lr~r~gzsszrnaXloorr)
M Z C T O T O ~ ? L ~ I L R K RS KSKS ( oloperidrza (Burni. f.)C'opcl.
(I'iiyrnatodes scoloperidrza (Burni. f.)Ctiiiig)
(Polypodz~~nrphyrr~atodesL.)
Mzcrosorurn ~ L I ~ T ~ ~ c ~ T ? , T KS K R R s k R s k(Dl.) Copt-1.
( I 1 / ~ y ~ n u t o d ~ sr~zqresceris(BI.)J.Sni.)
(Polypodzurri nzgresceris BI.)
*.bTzrrosor~~rr~sp.
P y r r o s ~ alariceolata (L.)Faru,. R S R RSK KSK K R R K KSK
(Pyrro,zu arlria.9cer~9(Fnrst.)Ctiing)
( C y c l o p h o r ? ~ ~ Dcsv.)a d r i a ~ c e r ~ s
Pljrroszu longzfolzu (Burni. f.)hIortnn
((:?irlophoru.s ucrostzrhozdes Pr.)
P?jr,rosza ~~rlrn~rrularzfolza(S~v.)C'tiing
(Cyrlopiiorus r ~ ? ~ n ~ n ~ ~ ~ l a r z f o l z u sC'.C'tir.)
R K R R
SK S R i K r s K
PTF:RIDAC'EXE
Acn~ntzci~urna ~ ~ r e ~ ~ r nL. R K K P RS R R KSK RSK
Acrostzci~urri T ~ C ~ ( . Z O T ? L T ~ LLVilld. R K K R S
Pztyrograrnrnu calornelanor (L.)Link R R S K R KS R R K S k RSK R K K RSK SK
((:i,ropterz~ r.alornelanos I i i d . )
Pterz.9 asperuln .I.Sni.
Pterzs eriszforrnzs Burin .f.
Pterzs puczfiru Hirron.
Pterzs quadrzai~rztaKrtz.
Ptrrz,$ tr~purtzfaSa.. R
P t r r z ~uzttata I,. R K K S K R S K R R R K
SCHIZ.AE.AC'E:\E
Lyqodzl~ni( . z T ( . L T L ~ L ~ ~ ? L ~ L( B ~ ~ r n i . ) S u , . R KS RSK
Lyqodzum fleruoi7~rn(L.)Sa..
Lygodzurn rnzcrophyll1~7rr((:av.)K.Br.
(Lygodzurn i c u r ~ d e ~ ~ s(L.)Su,.)
Sciiizaea dzrhr~tornu(L.)Snl.
SELAC;INELLXC'EAE
Selaqznella ,:ai~leirer~.sSpriiig
Si,layzriella hrlfrrz \\'arb.
S r l a g z ~ ~ e l l aplilriu (Drsv.)Hirri~n. R R R R H R
Sr~lugzriella~r,zldr,~ro~r'zz(Dcsv. r x Poir.)Bakrr
Splagznellu sp.
THELYPTERIDACEAE
A r r ~ p l i ~ r ~ ~ ? ~ r ~ nz r n r r ~ e r ~ u n ~(B1.) Hnltt liin r S r R R i R s
( Dr!jopterz~zrn~rrf.rsaO.K.)
Ciirzstr,lla urzrlu (D.Don) Holtt~ini
(('yclo.sor~~s,:f.arzdu~(D.Don)C'tiiiig
sc.nsrl ; i ~ ~ r t .jav.)
C'hr.25ti~llapurrzgztzra (I,.) I x v . S
( D r y o p f e r z ~arnbozrie7~~z.sO.K.)
C'i~r~zstella~ u h p ~ ~ h r s c e ~ ? ~(Dl.) Hnlttum
( Thi,lypti,rzr ~ ~ r m a t r a n a(v.X.v.R.)K.Ia.ats.)
110 R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59. No. 2
ilPPENDIX I. Continued.
1886 1897 1908 1920 1922 1924 1929 1932 1934 1951 1979 1982 1983
Cyrlosorus cf.z~~terr?rptus(\\'illd.)Ito
Marrotiielypterzg polypodzozdeg (Hook.)C'tiing
Macrothelypterzs setzgera (BI.)C'hing
( Thelypterzg setzgera)
hlucrotiielypterzs torregzana ( G a ~ l d . )Ctiing
(Dryopterzs ulzgzriosa C.C'tir.)
AZfetuth~lypterzsflacczda (BI.) Holttum
(Dryopterzs flacczdu O.K.)
P~~eurnatopterzgtruncata (Poir.) Holttum
(Cyrlosorus trunratus (Poir.)Fara..)
S p i ~ u e r o s t e p h a ~ ~ o sper~r~zger(Hook.) Holttum R R R K R
iCyclosorlis m r g n p / ~ y l l ~ ~ s(hlett.) C'hing)
(Dryopterzs n~egaphyllaC'.Ctir.)
(Tl~elypterzsrr~egaphylla(hlett.)K.Iu~ats.)
Sphaerostephanos polyrurpur (B1.) Copel. S
( M e s o c i i l a e ~ ~ upolycarpa Bedd.)
Spl~aerostepiiario,sI L T L Z ~ ? L S (L.) Holttunl K R K R S R S R R RSK r S K
(Llryopterzs ~ i ~ ~ z t aO.K.)
\'ITTAKIXC'EAE
A ~ ~ t r o p h y u r n R R R RSKretzrulatlin~(Forst.)Kaulf.
[ + Ar~trophy~irn Bl.]~ a l l z f ~ l z ~ ~ ~ n
Vzttarzu u~~gurtzfolzuBl. K
Vztfarzu elongatu Sw. K RSK
Vztturza eriszforrr~zgSIV. K R
Vztturzn rogterzfolza L2'illd.
S P E K N A T O P H Y T A
AIZOXC'EAE
Ses7~vzun~port7~lacagtrurn(L.)L
AhIARANTHAC'EAE
A r n a r a r i t h ? ~ ~ L.s p z ~ ~ o s u s
Cyatliula prostrata (L.)BI
R K R R R
XSAC'ARDIACEAE
B ~ ~ c l i a ~ ~ u ~ ~ z aa r h o r e s c e ~ ~ s(BI.)BI
Gluts rengiiag L.
,\la~~gzfcraZ ~ L ~ Z C UL.
Spor~dzasrnornbzn L.
( S p o ~ ~ d z a s1uteu L.)
Spor~dzugpznnata (L.F.)Kurz
(Spondzag rnarigzferu \\'illd.)
R
R
RSK
K K
RSK
APOC'YXXCEXE
A l s t o ~ ~ z nsciiolarzg (L.)K.Br.
Cerbera n~ar~gliu,sL.
Ochroszu opposztzfolza (Lmk)K.Sctium
(Ochrosza sallihrzg BI.)
R R K R S
S
R S K r r s k r s k
XRXC'EAE
Alocasla lor~gzlobaLIicl. R K R R
AK.-\LI.-\CEAE
Arthrophyll~irnjuuanzcunL BI.
Polysrzas nodosa (BI.)Sccm.
Sciieflera polyhotryu (Lliq.)\'ig.
R s K KSK
K
K
R
RSK
K
K
R
ARISTOLOC'HIAC'EAE
Arzitolorhza tagala C h a m RS K R KSK RSK KSK
ASC'LEPIADXCEXE
Ceropegzu ruruzflora Hassk.
Cy~~anciiunLovulzfolz~irnLVight
(Cyriurirliurn laeve (Bl.)K.Sctium.)
R
S
R R s
K
R s K R SK RSK
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 111
APPENDIX I. Continued
Dzschzdza cochleata Bl.
Dzschzdza hzrgata (BI.)Drcnc
Dzschzdza ~ ~ ~ ~ r n n ~ a l a r z aR.Br.
Heterosternrr~aacurnzriutanL Drcnr
( H e t e r o s t e n ~ m ac h r y s a n t h u n ~(Hassk.)Borrl.)
Hoya dzvergzfolza BI.
Hoya l u c l ~ ~ ~ o s aBl
Hoya sp.
A2far,sderi~asp.
Raphzsternn~ahooperza~~urn(BI.)Drcnr
Raphzsternrnu sr).
Tylophora agthrr~atzca(Koxh.)LV.& A.
Tylophoru erzlzs C'olrt~r.
Tylophora ter~azsBI.
BEGONIAC'EAE
Bego~?zazsoptera Drvand.
BIGNONIAC'EXE
Cresreritza c?yete I..
Raderrnarheru ylaridulosa (BI.)XIicl
BOhIBAC'XC'EAE
Darzo zzbethzr~a~Xlurr.
Bornbur rezba L
(Salrnalza rr~aluharzca(DC)Sctiott & Endll.)
C'ARICXCEAE
('arz~ u papaya I
C'XC'TXCEAE
Opuritza elatzor hIlll
( Opuritza ~ I L T L UXIiII )
COXIBRETXCEXE
Lurnnztzera racrnLo5a LZ ~ l l d
Termz??aLzu rutuppu L
C'OhlhlELIUACEAE
C'on~melznabenqhuler~gzgL
Pollza cf iec~~ridzflora(Bl )Bakti f
COhIPOSITAE
Aqeruturn cor~yzozdr.,~L.
B l a n ~ r abalsurnifr.ra ( L . ) D C .
B l u n ~ e ulacera (Burnl.f.)DC'.
Blurr~eulaczrizata (Roxt).)DC'.
Blurneu rzpurzu (BI.)DC.
(Blarnea rhznqrigtr DC'.)
Bll~rr~eagylvatz(:u (BI.)DC'.
Bliin~eateriella DC.
(Blurnea humzfi~sa(Xliq.)Clarkc)
Eclzpta prostrata ( L . ) L .
(Erlzpta alba (L.)Hassk.)
Eleutheranthera ruderal7s (Sw.)Scii.-Bip
R
K
R R S
S R K K K S
K RSK KSK
K KS
*
K S
R s K r s K
*
R
K R R K R R R R K R
S K R S K R RSK RSK S RS R S H
RSK RSK KS R R KSK RSK S RSK R KSK RSK
S S S
RSK RSK R S R R KSK RSK S RSK K RSK RSK
K R R K
R K RSK S K K
R K RSK R S R R RSK RSK R R S
R R
K R K K R
R R R R R K
S
I12 R. J. WHITTAKER ET AL. Ecologrcal Monographs
Vol. 59. No. 2
APPENDIX I. Continued.
Err~zlzaorichzfolza (L.)DC. r x LVight R
(Ser~eczor o r i c h ~ f o l z ~ ~ , ~(L.)lIornch)
Ereci~tzteri~zeraczfolza(L.)Rafin, r u DC'. R S RS
Ereci~tztesvulerzarizfolza (LVolf)DC'. R
Erzqerori lznzfolzus \\'illd. ! R K R
*Erzgcror~sp.
Eupator.zurn odoratarii L. R RSK RSK
Gy??uraprorl~rnhe??~(Lour.)hIcrr. R R r r k r k R R S R
hfzkar~zucordata (Burm.f.)B.L.Rohinion R S S R r R s r s K R K R RSK R
Placheu zridzca (L.)Lcss. ! R K RSK RS R R RSK RSK R R R S
Poroph!jllarr~raderale (Jacq.)C'ass. R R
Sy~?rdrr,llnnodzflora (L.)Garrtn.
Verno??ia arhorea Burti.-Hani. R r R r R R
Verr~oriiuczriereu (L.)Less. R K R K R S R R RSK RSK R R RS
K'edelza bzfloru (L.)DC'. R R K RSK R S R R RSK RSK RSK R R S RSK
CON\'OL\'T-LAC'EAE
Iporrioea albu L.
Iporriora dzgztutu L.
Ipornoeu glaherrzrria Boj.
Ipornoeo graczlzr R.Br.
Iporrioea pes-raprue ( L )R Br
Ipon~oeastolo~~zfera(C'yr.)Gniel.
Ipon~oeatuba (Sctilcchtcnd )G.Don
A2ferrerr~zupeltata (I,.)llcrr.
Operrulzriu sp.
R R K
RSK
RSK
RSK
S
RS
RS
R S
R
R
R
R
R
R
R
R
S
RSK
RSK
RSK
R
S
RSK
RSK
RSK
R
RSK
RSK R
R
R
S
K
RSK
R
K
RSK
R K
R
C'RASSIJLXC'EAE
Kalarici~oepzr~riata(Ln1k)Pcrz
CUCURBITACEAE
Bryor~opszslacznzosa (L.)Naud.
Cocczriza gra??dzs (L.)\'olgt
(Cocczriza cordzfolza Xuct. non C'ogn.)
Luffu rglzr~drzcaRoerli.
Luffa 711.
Afelothrza sp.
Trzchosarithes hracteata (Lmk)\higt RSK R S r r s k r s k
C'YC'ADXC EXE
C'ycas run~phzz\Iiq R K RS R R RSK RSK
C'YPERAC'EAE
Cyperus rylzndrostuchyr Boeck.
Cyperur ~ a v a ~ ~ z c ~ ~ sHoutt
(Cyperus peririat~~sLamk)
Cyperus kyllzngzu Endl.
(Kyllznga rno~~orephalaRot t h.)
C'yperus odorat~lsL
Cyperus pedur~culat7~s(R.Br.)Kcrn
(Re~rizrearriarztzrnu Aubl.)
C'yperai a r i c z r i a t ~ ~ ~Pnir.
Fz.rr~hrzstyl,srynLora R. Br.
(Fzrnhrz,stylzs spatiiacea Rotti.)
Fzrnbrz,stylzr s p .
Sclrrza czlzarzs Nccs
R
R
RSK
R
R K
RSK
R
R S
R
R S
RS
KS
R
R
R
R
R
RSK
S K
RSK
RSK
R
R s k
RSK
DIOSC'OREAC'EAE
Dzorcorf,a bulbzfera L.
Dzoscorra ~ L I L T ~ T ~ I L ~ U ~ Z ULarlik
(Dzoscorra opposztzfolza L.)
Dzosrorf.a spp.
ELAEAGNAC'EAE
E l a r ~ ~ g r ~ a slatzfolza L
ELAEOC'XRPXC E X E
Elaforarpui glabrr B1
113June 1989  RECOLONIZATION AND SUCCESSION ON KRAKATAU
APPENDIX I. Continued.
1886 1897 1908 1920 1922 1924 1929 1932 1934 1951 1979 1982 1983
ET-PHORBI-\C'EXE
Acalyphu z ~ ~ d z c aL. 1 I
Ar~tzdf,srna~ U T L Z ~ S R(L.)Sprrrig.
Antzdt gnLa gl~aesernt~zlla RC;arrtrl.
Ar~tzdr,srnar n o ~ z t a n u ~ nBI. K R RSK RSK
Brtvzl~~zac e r r ~ a u(Po~r.).\l.A. S s s SK
B r z d f . 1 ~ ~ S r s R R R K RSKrnonr~zra(Lour.).\Icrr. R s
(Brzdf,lza tvrrzrr~toguBI.)
Brzdrlza gtzpularzs (L.)Bl. R R s R s K S
* *cf Brzd(,lza SII. ( ~ i o tB. rr~oriozra)
C'luorylon polot (B~irnl.f.)hIrrr. R R r S r s
Eupl~orhzuatoto F ~ r s t . f . R K RSK R R R RSK RSK S S
Eupl~orhzahzr.ta I.. I
Euphorbza th,yrrlzfolzu L. 1
Errmrcarza aqallorl~aL. K S K S R R RS s
Glochzdzon b o r n e e ~ ~ s f , R(hl.A.)Bor,rl.
* * * *Glvchzdzori sp.
Horr~aluntl~uspop1~1nf.1~~P a x R R R R R R R R R
A2fucaranqatnnnr.zus (I,.).\l.X. K RSK R S R R RSK RSK RSK R RSK RSK
hfallotas ~naltzqlaridalosu(BI.)Rchh.f.& Zoll. S S s s K
(Mallr~tusr r l ~ l a c ~ a r iU T .\I A . )
*hfallotl~ssp.
Marizhot erculrrlta C'rantz I I
(AZfur~zhutatzlzssz~nuPohl)
P h y l l a ~ ? t h ~ ~ , s (Dalz.).\l.X.zndz(~~,s R
Ph!/lla??th~~s (Brrltti.)hI.X.r r ~ z c r o r a r p ~ ~ s  R
*cf. P h y l l a r ~ t h r ~ rsp.
RZC.ZTLILS L.r o r r ~ n i ~ ~ n z s  I
R RS RSK R R R RSK RSK
GESNERIXCEXE
Af!,schy??u??thi~slorigzfloras (BI.)DC'. R
( Trzciiospor.urn longzflorug)
Aeschyriaritiias pulciirlirr~Bl. R
(Trzrho,sporarri palciirurrr BI.)
Aehrhy??a??thas r.adzcari 7 .Jack var pulcher - K R R R
- (BI.)G. Don
Aesr.l~y??anthar,,olabzlzs .Jack  R R R R R
(Trzcho,,por.~~rnvoluhzle Yees)
Cyrtu??dra salcata B1. R R S R R R s R s R R R R
+ C'yrturldra sa??df!z D r \'r.]
~ z k ~ n L o t a r ~ u , s R
*
harbuta Jack
Dzdyrnocarp~~ssp.
<:00DENlX('E.-\E
Scarwolu tacrada (<:aertn.)Roxi~. R RSK RSK R S R R RSK RSK R K R RSK RSK
(Scarvola fiutrsrf,ns Krause)
(Sruewola serzcra Vahl)
(Sruewola koerizgzz Vahl)
c;RXhIINE.AF: 

Cyrtororcun~oryphyllun~(Hochst. r x 

- Stcrid.) Stapf 

(Parizcurn pzlzpeg srrs & Xrn.) 

C'yrtococcum patens (L.)A.C'amus 

( P a n z r u n ~trzgonurn Rrtz.)
Dactylortenz7~n~o e g y p t z ~ ~ ~ r ~(L.)Richt
Dzgztarza rhopalotrzrl~aBusc.
Elt 7~sznt.zndzca (L.)C;arrt n.
Eri~grostzsarnahzlzg O . K .
Erzochloa proceru (Rctz.)C'.E.Hui~t~.
(Erzochloa rurrlosa (Rctz.)O.K.)
Irr~peratacylzridrzca (L.)Brauv. R K R K R S R R RSK RSK R R S RSK
I s c l ~ a e ~ n u r nT ~ I ~ L ~ Z C Z L T RL. R K RSK R S K R RSK RSK KSK R RSK
114
ilPPENDIX I. Continued
Lepturus repens (Forst.f.)R.Br.
(Morierma repens (F0rst.f )Beau\.
~Veyraadzan~adagagcarzenszsHook..
ivar. zollz~~gerzHook.f.1
Oplzsrne~~uscon~posztas(L.)Brauv. 

( H ~ p l ~ s ~ n f ~ r i u s 
C O T ~ ~ O S Z ~ U S )
O ~ ~ Z S ~ I L ~ T L I L ~aridalatzfolzas (Ard.)Brauv.
Pagpalarn cor~jagatarnBrrg.
Paspalurn wagz~~aturnSwartz
P e r ~ r i z s e t ~ ~ r nrnacrostachyan~(Brogn.)Trin
P o g o ~ ~ a t h e r u n ~parizcearn (Lan1k)Hack.
SaccharanL o f i c z ~ ~ a r u r nL.
SaccharanL s p o n t a ~ ~ e u mL.
Spzrizfer lzttoreus (B~irm.f.)hIcrr.
S p o r o b o l ~ ~ sherteroari a s Hitctic.
T i ~ u a r e azr~volatu(Forst.f.)R.& S.
GIJTTIFERAE
Calophyllurn zriophyllun~L
HEKNXsDIXCEAE
Herriar~dzapeltuta XIrissn
[ + H e ~ n a n d z asonora L.]
HYDROC'HARITAC'EAE
Halophzla oualzs (K BI )Hook f
LABIXTXE
Hyptzs b7-euzpes Poit
I.AIIRACEAE
Cassytha filzformzs L
LEC'YTHIDAC'EAE
Ba71~7~gt07~zaaszutzcu (L ) K I I ~ Z
P ~ U T L ~ ~ I ~ I T L Z Uualzda (Dl )B1
LEC~II.\1ISOSAE
Aderiurithe~apauor~znaL.
A e s c h y n o r n e ~ ~ e L.z ~ ~ d z c a
Alhzrza ciizner~szs(Osb.)hIrrr.
Alhzrza lrahbeck ( L . ) B t h .
Alhzrza retasa B t h
Cuesalpznza b o ~ ~ d ~ ~ r(L.)Roxt]. 

(Caegalpznza h o n d ~ ~ c e l l a 
Flrm.)
[ + Caesulpzriza crzsta L.]
Canauulza rnurztzrnu ( A u i ~ l . ) L r t ~ .
Canaualza rrlzrrocarpa (DC.)Piprr
(Car~avalzaoht?rszfolza Auct. rlorl DC'.)
Casszu szurrlea Lrnk
Crotolarza m u c r o ~ ~ a t aDrsv.
(Crotolarza strzata DC'.)
Dalbergza rundenateriszs (Drnnst.)Prain
Derrzg ellzptzra (Roxh.)Btti.
Derrzg i ~ r t e r o p i ~ y l l a(LVilld.)Back.
Derrzs s r a n d e ? ? ~(Roxi~.)Btti.
Derrzg trzfolzata Lour.
Desrnodz~~rntrzfloran~(L ) D r .
Desrrlodzurn urnbelluturn (L.)DC.
Dolzchog sp.
Eritada phageolozdes (L.)hlrrr.
Erythrzr~afasca Lour
Erythrzna orze~~talzs(L.).\lurr. 

(Erythrzna uarzegata L. var. -

- orzeritalzs hIrrr.) 

I~~dzgoferazollzr~gerzar~ahIiq.
ITL~SZU T t i ~ l l .~ T ~ L ~ I ~ I Z T L ~ T L S Z S
Leucuer~aleacorephala (Ln1k)Dc LVit
I L ~ I L ~ U T L U DC'.u c a n ~ z r ~ u t u
R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59. No. 2
K KSK r S r K r s k r s k
R S R K R s K R s K R R K RSK
R R K
R K
R K
R K
RSK
KSK
RSK
KSK
S
R S
RS
R S
1
RS
K
R
K
R
R
R
K
R
KSK
RSK
KSK
S
S
RSK
RSK
RSK
s
R
R
1
RSK
R S
KSK
K
R
S
R S
S
RS
KS
S
R SK KSK RS R R RSK KSK KSK R KSK RSK
K KSK R S K RSK KSK KSK R K RSK
R r r R
RSK RSK R S R R RSK RSK R K R RS SK
K K RSK KS R K RSK KSK KS RSK R RS
S
RSK
R
S
S
S
I
R K
R
~
R S k
R K
KSK
R S
KS
R
R
S
R K
KS RSK
RSK RSK R S R K RSK KSK R S KS
R K K
RSK
K
K
S
K
K
KSK
K
RSK
K
R S
KSK
R S
R S
S
RS
R
R
K
R
R
R
R
R s k
RSK
KSK
r s
K s k
I
RSK
RSK
K
r s K
S RSK R
R
K
K K
R
RSK
K
RSK
K
R R R R R
115June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
Mucuna gzgantea (\\',lld.)DC. 

Mucuna prurzens (L.,DC. 

Mucu~rasp. 

P h u s e o l ? ~ ~ C;.F.hIa?;.
udrnantl~?rs
Pzthrcellobz~~rrl~ ~ r r ~ b e l l u t ? ~ r r ~(\'ahl)Bth 

(Pztl~ecolobz~~rn
urrrbellaturrr B t h . )
Pongarrlza pzn~rata(L.)Pierre
Serzanthus grandiflora Bth.
Sopl~oratorne~atosuL.
Vzyna marzna (Burm.f.)hIrrr.
LIL1AC:EAE 

Pleorrlele ellzptzca (Thunh.)'J.E.Br. 

Srrrzlas zevlanzca L. 

XIALPIGHI-ACEAE 

Trzstellateza australastae A.Rich 

MALVACEAE 

flzbzscus tzlzaceus L. 

Thespesza popul~aea(L.)Soland. ex Correa 

MELASTOXIATACEAE 

Clzderrlza hzrta (L.)D.Don 

hledznzlla esznaza 

hledznzlla ~ f .pterocaula BI. 

Medtntlla spectosa (Reinw. ex BI.)BI 

Melastonla afine D.Don 

(Melastoina polya~athuinBI.)
XIELI.AC:EAE
Dysosyluin arborescer~s(BI.)Miq.
Dysosyluna yaudzchaudzanurrr (A. Juss.)hIiq
(Dysosyluin anaoorozdes hIiq.)
Melza azederach L.
Xylocarpus gra~aatunlKoeli.
Xylocarpus n~oluccenszsRoem.
XIEN1SPERMAC:EAE
Cyclea barbata Miers
Pertcainpylus ylaucus hIirrs
Stepha~azajaponzca (Thunh. ex XIurr.))
'var. dzscolor (hIiq.)Formanj
~ t n o s p o r aglabra (Burm.f.)Merr.
(Tznospora corzacea (BI.)Beumee)
(Tz~aosporacrzspa (L.)Diels)
XIORACEAE 

Artocarpus elasttcus Reiliw. csx B1. 

Artocarpus zTaczsa (Thnlih.)L.f. 

Ftcus arrrpelas Bu1m.f. 

Fzcus annulata B1. 

Fzcus asperzuscula Kulith & Bouche 

(Fzcus leptorrynclra Val.)
Ftcus callosa \trilld.
Fzcus elastzca Roxb.
Fzcus fistulosa Reiliw. ex B1.
Ftcus fulva Reinxv. r x BI.
Ftcus glonaerata Roxh.
Fzcus heterophylla L.f.
Fzcus hzrta Vahl
Ftcus htspzda L.f.
Fzcus leptcarpa BI.
Fzcus rrrontar~aBu1m.f.
(Fzcus yuerczfolza Roxb.)
Fzcus pada~aaBurm.f.
(Fzcus toxtcarta L.)
Fzcus pubznerl~zsBI.
Fzcus retusa L.
KS R R RSK RSK R K K RS KSK
s
*
K RS RSK
KS RS K K S
K RSK RS r r s k R s k RSK R R RS
S S S
K RSK S s k s k R
R K RSK RS R R RSK RSK R R R K RSK
R R r r R
R R R R R R R
R K RSK RS R R RSK RSK RS RSK R RSK RSK
R S R r r s r s
S S S R R R R
R R R
R R
R RS
S RSK RS R R RSK RSK R K R S S
R
K R RSK RSK
R r K R S R K R K
R R R R
R
RS R R RSK RSK R R R RS
RSK SK
RSK SK
R
R s s s
R
RSK RSK R R RSK RSK
RSK RSK R R R RSK RSK
R
R
R
r s k R s k R R S K
R K
R R K
RSK RSK
S
116 R. J. WHITTAKER ET AL. Ecolog~calMonographs
\'ol. 59. No. 2
APPENDIX I. Continued.
1886 1897 1908 1920 19221924 1929 1932 1934 1951 1979 1982 1983
FZCILSrzbes R P ~ I I W . R R R R R R R RSex Bl.
F Z C ~ L Sseptzca Burrn.E. K SK RS R R RSK RSK R RS R RS RSK
F7cus szrhulata BI. R R R R R
F ~ C Z L S Miq.1 z ~ n ~ a t r 1 ~ r ~ a S
F ~ ( , I L stznctorza L.f. ssp. gzbbosa - S s k s k R R RSK RSK
- (BI.)Corlier
( F z c . 7 ~ ~gtbbosa Bl.)
Fzcu.s uarzegafa U1 R R r R R R R R K RSK
hIYRSIN.\CE.\E
.4rdzsza I L I L ~ I L ~ ~ Z SVabl
[ r 4rdz5za ellzptzca Thunh.!
RSK R R R RSK
R R K R
Y\ CTAGIA 4CE 4 E
Doe rhnuza erer ta L
R s K 1 s
ORCHIDACEAE
.4cu~~thephzppznrnparutflorun~Hassk.
.4cr.topszs 3at;aTizca Rpinw.
A ~ Iostopliyllu~r~btcuspzdatzrn~J..T.S.
Ag~ostophyllzrindenbergert .J..T.S R R R R
A p ~ ~ r n d z c u l areflexa BI. R R R
ilrundtna yrarnznzfolza (D.Don)Ho(.hr. R K R K RS R R RSK RS S
iA7~undznaspeczosa BI.)
B71lhophyll1~~r~p z ~ r p ~ ~ r a s c e ? ~ ~T . & B.
B ~ ~ l b o p h y l l u n ~1 ~ n g z ~ t c z ~ l a t 1 ~ 7 1 ~Rcbb.f.
Bulbopllyllun~sp.
Calanthe angusttfolza (Bl.)Lindl.
Culanthe sp.
Coeloyyne longzfolza Lilidl.
Coelogyne rocllusseriz De l'r.
C!j7r~btdzurr~finlaysonzanuin Lindl.
Cy7r~bzdzun~pubescens Lindl.
Ct~7r~btdzu71~strr~ula~isRolfe
Dcridrobzuin acz~rnznatzssz~nu~n(B!.) Lindl.
Dr7adrobzurri cru7nenatun~Swartz R r R R
De7~drobzurr~~ r ~ u t a b t l e(BI.)Lindl. R R R R
Drndrobzun~secundu7r~(BI.)Lindl. R R R R
De~~drobzurr~sp. (or spp.)
E7.za anriulata (BI.)B!.
Erza oblttterata (Bl.)Rchh.f.
Erza retasa (BI.)Rchb.E.
E u l o p h ~ agrarr~zneaLindl.
E ~ ~ l o p h z amacrostachya Lilidl. RS R R RSK HSK
Ezrlophza syzralzda Lindl R R K K R
Eirlophza zolltngorz (R(.hh.f.)J..I.S. R
Galrola kuhlz~(R(.hh.f.)Rchh.f. R
Gendorurn purpureurn R.Br. R K R
Goodyera colorata (BI.) BI.
Goodyera cf. repens
Goodyera sp.
(~rain7r~atopl~yllu71~spectosurn BI. S
Habenarza sp. R
1,zparzs uzrzdzflora (B!.)Lindl. R R R R H
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
APPENDIX I. Continued.
1886 1897 1908 1920 1922 1924 1929 1932 1934 1951 1979 1982 1983
Lzparts wrayt Hook.f.
Ltparzs sp.
hlacodes petola Lindl.
Malaxzs latzfolza J.E.Smith
RS
S
R
R
R
R
R s
R
R s
R
*
R
(Mtcrostylzs lntzfolza (.J.E.Smith).J..T.S.)
"V'en~zlzaarayoana Gaudi(.h.
Nervzlza puri<.tata(BI.)Schlect.
Obrronza n~onstruosa(BI.)Lilidl.
Oberonta sp. (not 0 . rrlo~astruosa)
Pt~rtstylusyoodyerozdes ( D DonjLindl.
Perzstylus graczlzs BI.
Prrzstylus yrandts Bl.
Phazus ta~akert;tlltae(\V.Ait.)BI.
Pllazus sp.
Pl~olzdotazrrrbrzcata Lindl.
Podo<.l~zlus6ari.1:ari.u~
RS
R
R
RS
R
RS
S
R
R
R
R
R
R
R
RsK
R
R
R
R s K
R
R
R
R
R
R
R
R
R
R
RS RS
R
RS
R
* *
R
Spathoglottzs plzcata BI.
Taenzophyll~~n~sp
T l ~ r z z s p e r n ~ ~ ~ n ~corrra~as.J..T.S.
Tl~rzxsperrrru~r~sp.1 (not T , corrlans)
Thrzxsperrrli~rrrsp.2
Tropzdza cu7~cultgozdesLilidl.
Vrydagzyneu alhzda BI.
Vrydagzynet~sp.
Zeuxt~aeyraczlts BI.
R K RSK RS
R
S
R
R
R
R
R
R
r
RS
R
r s k
RSK
R
R
r s k
R
R S RS
P.ALXI.AE
Calarrlus unzfartus BI.
Calarrlus vz~r~znaltsLVilld.
Calarrlus sp.
Coros nurzfrra L.
Corypha utari. Lamk
Lzcuala spznosa Thunb.
O~acospermatzg~llarzurrr(Jat.k)Ridl
(Or~cospe7~rrrafilan~entosun~BI.)
R K RS RS
S
R R RSK
R
RSK
K
K
S
S
RSK
R
R
R
R
S
S
RSK
RSK
K
RSK
PAKDANAC:EAE
Freycznetza ip.
Pa~adanustvctorzus Soland. ex Park R K RS RS R R RSK RSK RSK
R
R RS RSK
PASSIFLORACE-AE
Passzflora foetzda L
PIPERACEAE
Pzper aduncurrl L.
Pzper blurnez (hIiq.)Back.
(Pzper inalain~rzs(non L.)BI.)
Pothonrorphe suhpeltatu (\Villd.)XIiq
(lfeckrrza ~ ~ r r ~ b e l l a t a(L.)Kth. var.
- subpeltata DC.)
R R R r R
R
R
RS
R
RSK
R K
POLYGOK.ACE.AE
.4ri.tzyo~ao~~11,ptopusHook. br Arn
PORTITLAC:AC:EAE
Po, tulac(~i~ler-acmaL
RAKCNCULACEAE
Clenratzs sn~zlac~folzaVv'all. R R K R K
RHAXINAC'EAE
Colu6rtri.a a,zatzca (L )Brogn RSk s k R K R RS S
118 R. J. WHITTAKER ET AL. Ecological Monographs
Vol. 59, No. 2
APPENDIX I. Continued
1886 1897 1908 1920 1922 1924 1929 1932 1934 1951 1979 1982 1983
RTrBIACEAE
Guettarda speczosa L. RSK RS R R RSK RSK RSK R RSK RSK
Hedyotzs dtffusa \Villci. R R R
(Oldenlandza dzffusa (\Villd.)Roxb.)
Morznda cztrzfolza L. R K RSK RS R R RSK RSK S RSK R RSK RSK
Mussaenda frondosa L. R R R R R R R S
Mycetza 3at;ar~tca(BI.)Rrinw. ex Korth. R R
Nauclea excelsa (BI.) LIerr. ?
Neor~aucleacalycz~aa(Bartl. ex DC.)Mrrr. R RS R R RSK RSK R R RSK RSK
(Nauclea purpurascens Korth.)
Tare~anadasypl~ylla(LIiq.)Valet, ex Steeli. R
Tarer~nafragra~as(BI.)Koord. et Valet R R R
Ttnaonzus corrrpresszcaulzs (hIiq.)Boerl. R K r K R R RSK RSK
ll~acarzaferrea (BI )DC. R S R Rs R s
RT-TACEAE
Cztrus sp.
SAPINDACEAE
Allophyllus cobbe (L.)Raensch. S
Dodonapa .r~zscosa.Jacq. s S
Enoglossunl rubzgzr~osurrr(Roxb )BI R r r
(Erzoglossunl edule BI.)
SAP0TAC:EAE
Planchonella duclztari. (B1anco)Bakh.f R R K
(Planrhonella nztzda Dub.)
R R R K R
SCROPHTLAR1AC:EAE
Lz~ader~azacrustacea (L.) F.v.hI.
Steinodza ?~ertzctllata(Mill.)Bold
SOLANACEAE
Capszcuin frutesce~asL.
Lycza~atheslae?~zs(Duna1)Bitt.
(Solanunl hlurrrzz Nees ex BI.)
Lycoperszcon lycoperszcunl (L.) Karsten
(Solar~unilycoper.szcuin L.)
Solanuin naelongena L.
Solanuin toruuna Swarta
Solanurrl verbasczfolzurrr L
RS
R R
r
R
r s k
R
r s k
R
STERC:TrLIAC:EAE
Melochta urrrhellata (Houtt.)Stapf
Sterculza foetzda L.
Sterculza urceolata .J.E.Smith
R RS RS R R RSK RSK
K
RSK R
R
RSK
S
SK
T.\CC.\CEAE
Tacca leor~topetalozdes(L.)O.K
Tacca palnlata BI.
S
R R
S
R
S
R
R RS R R RSK RSk
1-MBELLIFERAE
Centella astattca (L.) 1-rb S
TRTIC-\CE.\E
Dehregeasza longzfolza (Burm.f.)\trrdci, - R
- var. afir~zs
Leucosyke capttellata (Poir.)\Vedd. R RS R R RSK RSK R K R RSK RSK
(Mzsszessya capztellata (Poir.)Bakh.f.)
fzpturus argenteus (Forst.f.)\trrdd. RSK RS R R RSK RSK R R RS SK
(Pzpturus tncanus (Bl.)\trrdd.)
Pouzolzza zeylanzca (L.)Belili. R ' R R
119June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
APPENDIX I. Continued.
Vtllebrunea rxbescens (BI )Bl. R R R R R R R R RSK
(Oreocnzde ruhescens (BI.)X\.liq)
VERBESACEAE
Avzcen~azaalba BI.
(A?~zcer~ntarr~arzna(Forsk.)Vierh.
jvar. alba (BI.)Bakh.) ]
Clerodendruna dz~partfolturrlBI. R R R R
Cleroder~drurrrznerrrre (L.)Gaertn. RS RS r r R s K r s k
Lantana carrrara L. RS RS R R RSK RSK RSK R RSK RSK
Preinna coryrrlbosa (Burrn.f.)Rottl. & Wrilld RSK RS R RSK RSK RSK R R K RSK
(Preinna zntegrzfolza L.)
[ - Prenana obtuszfolza]
Stachytarplleta zndzca (L.)Vahl
Vztex glabrata R.Br.
Vztex panzculata Lamk
VITACEAE
Cayratza trzfolza (L.)Domin RS RS R R RSK RSK R R RSK RSK
(Colurr~ellatrzfolza XIerr.)
( Vztzs trtfolza L.)
Leea aequata L. R R ? R R R K R K R
Leea sanahuczna (L.)\Villd. S R R RSK RSK R R R RSK RSK
(Leea tndzca (Burrn.f.)hIerr.)
Leea sp. *
Tetrastzgina la~aceolartuin(Roxb.)Planch RS R r r s r s R R S RSK
ZINGIBERACEAE
Boese~abergzapandurata (Roxb )Schlrct. 1 1 1 1 1
(Gastrochzlus pa~aduratusRidl.)
Costus speczosus (Korn.)J.E.Smlth R R S R R R R R R R R
(Costus serzceus BI.)
Notes: 1. Lumnitzera racemosa, Excoecaria agallocha, Crotolaria mucronata and Casuarina equisetfolia were recorded on
Sertung in 1921, but have been placed in the 1920 column for simplicity. Only Crotolaria mucronata had not previously
been recorded. 2. Specimens of Dysoxylum collected in 1982 were attributed to D. caulostachyum (Tagawa 1984) but have
been assigned here to D. gaudichaudianum (for details see page 20). 3. It has sometimes been necessary to re-combine certain
taxa in the table as compared to earlier authors (e.g., we treat Nephrolepis biserrata as synonymous with N. exaltata, although
some authors have split them). For a complete list of such taxonomic revisions and problems see Whittaker and Flenley
(1982:25-29) and Bush et al. (1986a:2 14-2 16).
120 R. J. WHITTAKER ET AL Ecolog~calMonographs
Vol. 59. No 2
APPENDIX 11.
The complete plant list for Anak Krakatau 1930-1983.
BLECHU,\CE,\F
Stenochlaena palustrzs (Rurrn f )Redd
OLE.AhUR.ACE.4E
hephrolepzs cf cordzfolza (L )Pr
Aephrolrpzs lazrgutula (Forst )Pr
SCHIZ A r ACT 4 r
Lygodzuna czrcznraaturn (Burm )Sv
Lygodzun~Jlexuo~una(L )Sa
AKIS? OLOCHI,\CE,\F
Arzstoloclaza taqala Cham
ASCLTPI AD ACE AE
('yriarichurn oralzfolzun~ ight
Tyloplaora asthmatzca (Koxh )W k .A
Tylopliora cf tenuzs R1
Tylophoia sp
BIG UOUI.4CF.4F
Rndernaachera qlandulosn (B1 )lIiq
C.4KI(5.4CF.4E
C'arzcn papaya L
C.ASI.4KI\J.4CE.AE
Cnsuarzna equzsetz~olzaJ.R. k- G.Forst
COlIF3KETXCEAE
Termznalza catappa L
C'Ohll'OSITXE
C'msst~cephalurncrrpzdzozdes (Benth.)'
- S. lIoore]
Eclzptti prostrata (L.)L.
Erechfztes sp.
Erzgrron lzrizfolzus \t1illd.
Eupatorzum odoraturn L.
,tlzkaraza cordntn (Rurm.f.)B.L.Kobi11~~11
Porophylluna rudrrnlr (Jacq.)Cass.
IVedelzn bzJlora (L.)UC.
C'ON\.OL\-LL.4CE.AE 

Ipomoea grnczlzs K.Br. 

Ipornoea pes-capmr (L.)K.Rr. 

Ipornoea stolonzfera (Cyr.)Gmel 

June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU 121
APPENDIX 11. Continued.
Ipomoen tuba (Sch1echtend)G Don
1934 1949 1951 1979 1982 1983
A
CYC'ADACFAP
C'ycns rumphzz XIiq
CYPEK.AC'T..AF
ryperug jaranzcus Houtt
C'yperus peduriculntus (K Br )Kern
E I PHORBIACEAE
Aratzdesma ghnesenabzlla Caertn
Antzdesma sp
A!lacarangatannrzus (L )LI .A
COODTUI ACE AE
S c a e ~ola taccadn (Gaertn )Koxb
GKXhlIXE-AE 

Chlorzs barbata (L.) Swartz. 

In~peratacylzridrzcn (L.)Reauv. 

Ischnrmum mutzcun~L. 

Panzcum sp. 

Pogoriathrruna parizceum (Lamk) Hack. 

Saccharun~sporataraeum L. 

Spzrazfex lzttorrus (Burm.f.)LIerr. 

Thunrea zn7~olutn(Forst.f.)K.& S. 

HEKh.AUD1 ACE.AF
tfernaradza prltata LIeissn
+ flrrraaradza sonora L ]
LT.CYTHID.ACT. AE
Barrzngtoraza aszatzcn (L )Kurz
LEGI-1lIKOS.AE 

Albzzza rrtusn Bth. 

C'arsalpzraza boriduc (L.)Koxb. 

(:anal:alzn n~arztzmn(.Aubl.)L-rb. 

Llalbrrgza ~unghuhrazzBth. 

Dalbergza sp. 

llerrzs trzJolzata Lour. 

L)rsmodzurn un~bellatum(L.)DC. 

Erythrznn orzeritalzs (L.)\lurr. 

.tlzrnosa pzgrn L. 

Alucuraa gzgnritea (\Villd )DC. 

Phaseolz~ssp. 

Pzthrcellobiun~umbel la tun^ (17ahl)Rth 

Pongamza pznnata (L.)Pierre 

Sophora ton~entosaL 

l'igraa naarznn (Burn1 f )hlerr
\l ALV7.ACT.AE
flzbzscus tzlzaceus L
Thegpesza populnea (L )Soland ex C'orrea
122 R. J. WHITTAKER ET AL. Ecolog~calMonographs
Vol. 59. No. 2
APPENDIX 11. Cont~nued.
1934 1949 1951 1979 1982 1983
hlEL.ASTO\I.AT?IC'F -\r.
Ailelastoma a f i n e D Don .A .A A
LIELI.ACFAF
Dysoxylum gnudzchaudzanum (A Juss.)lIiq
Xylocarpus grnriatum Koen
hlOK.ACE.AE
Ficus fu11:a Keinlv. ex R1
Fzcus septzcn Rur1n.f.
llUS.ACE.AE
Musn paradzszaca L
OKCHIDACr A r
C'alnnthr sp
Dendrobzum crunarnatuna Suartz
Dendrobzum sp
kulophzn granaznea Lindl
Spathoglottzs plzcata R1
P.AKD.AN.AC'E.AE
Pandnnus trctorzus Soland. ex Park
P.ASSIFLOK.ACE.AE
Passzflorn fortzda
KH.AlIK ACE AE
C'olubrzna nszatzca (L )Brogn
KHIZOPHOR ACE.AF
Rhzzophora stylosn Griff
R17RIAC'E.AE
Morznda cztrzfolza L
Nronauclea calyczna (Bart1ex DC )Rlerr
Tznaonzus compresszcaulzs (lliq )Boer1
KL T.AC'F.AE
Murrnya exotzcn L
STERCILI.ACE.AE 

hlelochza urnbelleta (Houtt.)Stapf 

cK71C'ACEAE 

Pzpturus nrqentrus (Forst.f.)\Vedd 

\TKBEN AC'E.AT.

Premna corymbosa (Burrn f )Kottl k \Villd 

\'I TAC'E.A F
rnyratza trzfolza (L )Dormin
('zssu9 rrpens Larnk 7
-
1934 = collections in 1932, 1933 and 1934, all being 'seedling' floras. 1949 = collections by Petroeschevsky and van der
Pijl. A = species recorded on Anak Krakatau. a = species recorded only on Anak Krakatau, ? = uncertain identification. * =
identification to genus only, when other species in the same genus have been found. Names in square brackets indicate either
varieties or grouped species. For synonyms see Appendix I.
Sources: Docters van Leeuwen 1936, van der Pijl 1949, Borssum Waalkes 1960, Whittaker and Flenley 1982, Tagawa 1984,
Tagawa et al. 1986, Bush et al. 1986a.
June 1989 RECOLONIZATION AND SUCCESSION ON KRAKATAU
APPENDIX 111
Two species of unidentified mosses were found on Rakata
as early as 1886. but the first identifications were of Bryurn
~,oronarurnand Philonoris sectrnda, collected in 1906 (Ernst
1908). Between 1919 and 1932. Docters van Leeuwen (1936)
recorded over 33 speciesof mosses. The difficulty of collecting
and identifying these taxa has prevented a comparable collation
for the 1979-1983 period (Jones 1986b). At least nine
taxa recorded in the 1920s are still present on the islands:
Florlbur7darlaflorihunda (abundant in upland Rakata), Aerobryopsrs
longrssirna (ditto). Pelekrum velarurn, Tasithelium
ncpali7nsc,,I'tsicularia reticulata, Ectropothecium sp.. Calj.rnpt,rt,s
cf. tencrurn. Leucophanes sp.. Fissidens sp.
Mosses. commonly Fissidens sp.. were often found on the
bare. unconsol~datedash at low altitudes. They were also
found along termite trails. on the few rocks to be found, and
on dead wood and tree trunks. In the upper reaches of Rakata,
the covering of bryophytes was more ubiquitous and differed
in composition (Docters van Leeuwen 1936. Forster 1982).
The lack of a similar altitudinal range on Sertung and R. Kecil
is reflected in a less dlverse moss flora, from which those
speciescharacteristic of the cloud or "mossy" forest of Rakata
are largely absent (Jones 19863).One genus, Calyrnperes, has
been recorded from Anak Krakatau in 1982 (Tagawa et al.
1986).
Data for the Hepaticae are poor. Only one specieswas found
prior to 1919. but during the 1920s Docters van Leeuwen
(1936) recorded 38 taxa. mostly from Rakata alone. The canopy
habitat of much of this flora makes undersampling particularly
likely for this group. Of the recent surveys, only
Tagawa et al. (1986) have produced any identifications (six
taxa), these to a generic level. On Anak Krakatau in 1982,
Jones (19866) recorded a hepatic. tentatively identified as
.Ifarchanria sp., growing as a pioneer on the side of the island
remote from the vegetated areas. Further work on the collected
bryophyte material is in progress (Jones.personal com-
rnunicarion).
We are grateful to Dr. Barbara Parris (Royal Botanic Gardens, Kew) for revisions of the fern
taxonomy received subsequent to acceptance of this paper. These revisions were incorporated into
the text (including tables and appendices)but arrived too late for revision ofthe figures. In consequence
some graphs of species number against tlme contain minor inaccuracies. However, these errors do
not exceed eight species on any island in any single year, and in most cases the error is zero, one, or
two species. Such changes would be barely perceptible on the graphs.