}Science of relations between living organisms and their environment (Ernst Haeckel – 1866) } }Ecosystem is the basic system of ecology, not only the organism-complex, but the also the whole complex of physical factors forming what we call the environment (Tansley - 1935) }structure (parts) and }function (processes) and is }dynamic (orderly change called succession) } }Two main functions are ◦Transfer/Exchange of energy ◦Cycling of material (particularly nutrients) } Energy is the ability to do work Forms of energy: potential, kinetic, thermal, chemical, electrical, etc. 1st Law of Thermodynamics: energy cannot be created or destroyed 2nd Law of Thermodynamics: energy goes from a high quality to a lower quality during each energy transformation; while energy is conserved, it’s ability to due work decreases http://www.marietta.edu/~biol/102/ecycle.gif http://ideonexus.com/wp-content/uploads/2009/04/coalformation.jpg Image result for carbon cycle ecosystem Tracing these cycles helps to understand how we have modified them Image result for hydrological cycle Image result for hydrological cycle human impacts infiltration Impervious surfaces Withdrawal for agriculture, energy, and urban use Land use change Photosynthesis ßà respiration Image result for carbon cycle 1.Burning fossil fuels 2.Deforestation Diagram of nitrogen cycle above and below ground. Atmospheric nitrogen goes to nitrogen-fixing bacteria in legumes and the soil, then ammonium, then nitrifying bacteria into nitrites then nitrates (which is also produced by lightning), then back to the atmosphere or assimilated by plants, then animals. Nitrogen in animals and plants become ammonium through decomposers (bacteria and fungi). Image result for nitrogen cycle diagram Fertilizer production Burning fossil fuels Image result for phosphorus cycle Fertilizers Wastewater Detergents FEEDBACK as a consequence of interconnections Ecological Systems possess capacity for (a) self-regulation: negative feedback - deviation damping, stabilizing (b) self-adaptation: positive feedback - deviation-amplifying, destabilizing http://www.gerrymarten.com/human-ecology/images/02-8-english.gif Ecosystems are dynamic Biological systems are characterized by a capacity for directional change – the cumulative manifestation of positive feedback. Succession – ordered pattern of growth and development Increase in complexity and order as the result of controlled growth – decrease internal entropy http://www.dwtutorials.com/tutorials/images/stories/tuts/change_direction%5b1%5d.jpg Population dynamics Unconstrained Growth Constrained Growth (environmental resistance) Density dependent mechanisms (negative feedback) As population ↑, increasing mortality or decreasing birth rate As population ↓, decreasing mortality or increasing birth rate http://www.dls.ym.edu.tw/lesson/eco/expgrowth.gif Community and Ecosystem Dynamics r species (ability to reproduce rapidly), fast growing, effective dispersal mechanisms, wind borne seeds, short lived, vegetative or asexual reproduction, do not compete well with other species, numbers fluctuating widely, strong influence of density-independent factors K species (ability to maintain populations at their carrying capacity) species, slow growing, low reproductive rates, low dispersal rates, time lag to sexual maturity, diverting production or energy to defense. http://www.world-builders.org/lessons/less/biomes/bgifs/beartwocubs.gif Image result for fruit fly http://www.windturbinesyndrome.com/img/k-graph.gif Early stage Late stage Succession These are paralleled by two distinct environments: r-selecting environments – ephemeral, extreme, unpredictable K-selecting environments – equable, predictable, stable. DCP_1542.JPG DCP_3592.JPG Succession Mature communities with the highly developed interdependence of their constituent species and their complex network of interaction with the environment are the result of inherent processes of change – directional change akin to the growth and development of the organism. Organisms modify their environment, but in such a way as to allow other species to enter the community. This is the facilitation model of succession, a positive feedback process reinforcing change. Art:Primary succession begins in barren areas, such as the bare rock exposed by a retreating glacier. The first inhabitants are lichens or plants that can grown on bare rock. Over hundreds of years these “pioneer species” convert the rock into soil that can support simple plants such as grasses. These grasses further modify the soil, which is then colonized by other types of plants. Each successive stage modifies the habitat by altering the amount of shade and soil composition. The final stage of succession is a climax community, a very stable stage that can endure for hundreds of years. Primary succession – initial establishment and development of an ecosystem in an area devoid of an ecological community http://www.cas.vanderbilt.edu/bioimages/ecoregions/w70202lava-sea04214.jpg http://www.countrysideinfo.co.uk/successn/images/index1a.jpg Primary succession Island formation; dune formation, glacier retreat http://cache.eb.com/eb/image?id=95198&rendTypeId=36 Secondary succession – reestablishment of an ecosystem from the remnants of a previous biological community following disturbance Almost all old growth forests have been cleared in the US By Hannu - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5190488 Boreal forest one year and two years after a wildfire The Heathland Project area at the Woodland Education Centre. Cleared in 1993. Secondary succession The Heathland Project area at the Woodland Education Centre. Cleared in 1993. Secondary succession Human induced succession – agriculture, forestry, plowing, mining, fisheries, damming rivers, war, etc. Towards establishment of a climax state organic matter increases development of soil balancing of weathering soil chemistry reaches a balance water and drainage patterns established climate is modified by microclimate diversification and segregation of ecological niche development of negative feedback loops During Succession – how nature restores itself Organisms modify their environment in such a way as to allow other species to enter the community. A positive feedback process reinforcing change. Development leads to co-development Biodiversity begets biodiversity – the tree is habitat for many more organisms C:\bfath\biol105\biomes.gif Biomes of the world How do systems change over time? C:\bfath\Research\Misc\salzau\untitled.jpg Logistic growth from early to late successional stages Trends to be expected in ecosystem development (Odum 1969) Ecosystem Attribute Developmental Mature Stage Stage Community energetics Gross production/community respiration (P/R ratio) >1 ~1 Gross Production/standing crop biomass (P/B ratio) high low Biomass supported/unit energy flow (B/E ratio) low high Food chains linear weblike Nutrient cycling Mineral cycles open closed Nutrient exchange rate rapid slow Nutrient conservation poor good Overall homeostasis Stability (resistance to external perturbations) poor good Entropy high low Information low high Bioenergetic model of succession In early stages of succession, P>R and excess is channeled into growth and accumulation of biomass. Increase capacity and complexity of the energy storage compartments (total biomass of all species and trophic levels) as well as the complexity of energy transfer pathways. In late stages of succession, P=R as maintenance costs increase respiration Negative feedback maintains steady state, with little or no change in biomass (network, feedback, cycling). Logistic growth from early to late successional stages C:\bfath\Research\Misc\salzau\untitled.jpg Production Growth Quantity Protection Stability Quality Ecosystem services are extracted to exploit growth phase Human induced succession –deforestation, agriculture– moves the system back to earlier stage. Compartment model of the basic kinds of environment required by humans P1010701.JPG P1040239.JPG partitioned according to ecosystem development http://i43.photobucket.com/albums/e358/urbanscout/succession-subsistence-1.jpg Complex Systems Cycle: Holling’s 4-stage model of ecosystem dynamics Logistic growth only captures part of the cycle Exergy stored Connectedness Exploitation – pioneer stage Conservation – mature stage Release – creative destruction Reorganization Ecosystem succession in the collapse dynamic http://www.flightofthegoldengeese.com/wp-content/uploads/2010/07/Collapse_How_Societies_Choose_Fail _Succeed_Jared_Diamond_abridged_compact_discs.jpg http://images.bookbyte.com/isbn.aspx?isbn=9780062505958 http://faustianeurope.files.wordpress.com/2007/07/spengler.jpg http://ecx.images-amazon.com/images/I/5170RHkgciL.jpg All systems show signs of complex growth and DECAY dynamics The Collapse of Complex Societies (New Studies in Archaeology) }Schumpeter labeled the collapse, “creative destruction”, since it allowed for new configurations and innovation opportunities } http://www.crossingwallstreet.com/Free%20Money.jpg http://www.vanderbilt.edu/AnS/Anthro/Anth101/schumpeter.gif Collapse of Complex Societies (Tainter 1988) Complexification is limited as a problem solving strategy. “More complex societies are more costly to maintain than simpler ones… as societies increase in complexity, more networks are created among individuals, more hierarchical controls are created to regulate these networks, more information is processed … increasing need to support specialists not directly involved in resource production, and the like” (Tainter 1988). Complexity The Collapse of Complex Societies (New Studies in Archaeology) Collapse is the appropriate response of the system Develop- mental potential Connectedness Developmental opportunities result from the collapse }Out of the ashes of the old world came inventions… It is a cycle that the world has seen time and again, and that many have come to believe is an inexorable process the rise and fall of empires, followed by the rise of new empires, which eventually fall and are replaced in turn by even newer empires, in a repeated cadence of birth, growth and evolution, decay or destruction, and ultimately renewal in a new form (Cline, 2014, p. 175) number of connections Long-term succession of ecosystems: small-scale disturbances may support the development of the overall system. C:\Users\bfath\AppData\Local\Microsoft\Windows\Temporary Internet Files\Content.Outlook\ZY8LQDY7\adaptive cycle pic.jpg }System dynamics include a collapse phase due to external perturbation or internal constraints }Asymmetric relation between levels of organization give rise to functional hierarchies }The new system that emerges is often able to build on the “seed bank” of the previous one }How is this useful for understanding socio-ecological systems? }