Ecosystems are sustained systems; they flourish within their limits •Learning objectives •What is an ecosystem? •Understanding energy and its role in ecosystems •Food webs and trophic levels •How they change over time • Definitions •Biota – all living things within a given area •Biosphere – the region of earth where life exists •Ecosystems – community of organisms and its nonliving environment in which energy flows and matter cycles. • •What is needed to sustain life? •Sustained life on Earth is a characteristic of ecosystems. Earth as a system – no organism, population, or species can produce it own food and completely recycle it metabolic waste. •Science of relations between living organisms and their environment (Ernst Haeckel – 1866, in German oekologie) • •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) • •Fundamentals of Ecology – EP Odum (1953) Ecology •Atmosphere, lithosphere, and hydrosphere all have functional links involving transfers of energy and matter with the living material of the biosphere • When do you have an ecosystem? •Different size, different scale, different species •Borders can be vague •Natural (forest, field, wetland, stream, lake, etc.) or artificial (wastewater treatment ponds, agriculture, lawn) •Watersheds –Political and natural boundaries not typically the same •Common processes Where It All Started | College of Biological Sciences Czech Republic - Environment - European Commission •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) • Ecosystem has http://cdn.theatlantic.com/static/mt/assets/science/cool-space-picture-5.jpg We live in a world full of life. Nothing on Earth is entirely abiotic Rather it is With Life – conbiotic Earth energy balance (1st law) as a closed system Energy flow in ecosystems Energy input: solar radiation •Electromagnetic radiation – travels at constant velocity – speed of light Energy output and the planetary radiation balance In absence of atmosphere, long term-balance: net radiation = incoming radiation (mainly shortwave visible light) minus outgoing radiation (mainly longwave heat) = 0 The increasing concentration of greenhouse gases retains Earth’s energy from escaping to space, thus, warming the planet Sun’s energy drives global circulation Global Atmospheric Circulations | Physical Geography And, some used for photosynthesis to create organic, biological matter (biomass) Intro to photosynthesis (article) | Khan Academy Photosynthesis Process Stock Illustrations – 520 Photosynthesis Process Stock Illustrations, Vectors & Clipart - Dreamstime glucose •Used as basic building block of living matter •Energy stored in the chemical bond can be utilized later (in respiration) to do work Respiration – complimentary process to photosynthesis cellular respiration | Process & Products | Britannica Energy flow in ecosystems – trophic levels Primary Producers/ Plants Solar radiation Decomposers Input Herbivores (animals that eat plants) Carnivores (animals that eat animals) Omnivores (animals that eat plants and animals) heat heat heat heat heat Heterotrophs Autotrophs Functional activity of the ecosystem: transfer of energy and matter Fundamental functional activity – assimilation and utilization of energy and respiration Inside the ecosystem boundary is a complex, flourishing system Succession - Ecological dynamics http://www.macaulay.ac.uk/images/clip_image003.jpg Adaptive Cycle Growth à Quantitative increase Development à Qualitative increase "We must realize that growth and development are two very different things. You can develop without growing and vice versa.“ Tibor Vasko, 2009, www.solon-line.de/interview-with-tibor-vasko.html 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 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 http://z.about.com/d/forestry/1/0/3/q/Paper-_birch.jpg 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 Image result for primary succession glacier 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 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. Logistic growth from early to late successional stages C:\bfath\Research\Misc\salzau\untitled.jpg Early stage Late stage C:\bfath\biol105\biomes.gif Biomes of the world – nature flourishing within the climatic (temperature and precipitation) constraints Bioenergetic model of succession In early stages of succession, Pg>R and excess is channeled into growth and accumulation of biomass. Pn>0 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. Bioenergetic model of succession In late stages of succession, Pg=R as maintenance costs increase respiration. Pn≈0 Negative feedback maintains steady state, with little or no change in biomass (network, feedback, cycling). Ecosystem services are extracted to exploit growth phase Human induced succession –deforestation, agriculture– moves the system back to earlier stage. Odum, EP 1969 Strategy of Ecosystem Development Logistic growth from early to late successional stages C:\bfath\Research\Misc\salzau\untitled.jpg Production Growth Quantity Protection Stability Quality Compartment model of the basic kinds of environment required by humans P1010701.JPG P1040239.JPG partitioned according to ecosystem development Complex Systems Cycle: Holling’s 4-stage model of ecosystem dynamics Logistic growth only captures part of the cycle May 2010 http://i43.photobucket.com/albums/e358/urbanscout/succession-subsistence-1.jpg 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 The Collapse of Complex Societies (New Studies in Archaeology) 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 Benefits of collapse •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). The Collapse of Complex Societies (New Studies in Archaeology) Complexity > Adaptive Cycle - reoriented http://openlandscapes.zalf.de/ImagesWiki/Fig2_adaptive_cycle.jpg Burkhard et al. 2011 r Ω α K Develop- mental potential Connectedness Developmental opportunities result from the collapse number of connections Long-term succession of ecosystems: small-scale disturbances may support the development of the overall system. The Okay/Not Okay Principle of Human Induced Succession Multiple stable states – once it goes to one of the “not okay” basins it is hard or impossible to return http://www.gerrymarten.com/human-ecology/images/06-07-english.gif Summary •Ecosystems and urban systems are dynamic, undergoing patterned growth and development •Different stages emphasize different “priorities” •growth v. development •positive feedback v. negative feedback •change v. stasis •Disturbance is a natural part of the complex systems cycle •Disturbance may move system to “Not Okay” domain