Principles of Ecology: Humans in ecosystems

1. Principles of Ecology:Humans in ecosystems Seminar I November 5 and 9, 2010 Karl Seeley, PhD Hartwick College, Oneonta NY

2. Elements of a diagram language Source of energy: the sun; fossil fuel; water leaving a reservoir Passive storage: location for storing energy (potatoes in a store; coal in a fuel pile) Heat sink: represents the enforcement of the second law of thermodynamics; every useful process turns some potential energy into heat, and the heat sink is the undifferentiated environment into which it goes Potential-generating work: combination of the previous two items; work is done to store up energy in passive storage, and some energy is dissipated into the heat sink in the process Based on Howard T. Odum, Environment, Power, and Society, Wiley-Interscience, 1970

3. More elements Cycling receptor: responds to wave energy (such as light); arranges system to a higher potential-energy state, which is then released J1 Work gate: a flow of energy J2 is controlled by a flow J1; this can be as simple as turning on a faucet J2 Based on Howard T. Odum, Environment, Power, and Society, Wiley-Interscience, 1970

4. Still more elements Self maintenance: combination of work gate and passive storage; a flow of energy controlled by a work gate is used to build up a passive storage, which in turn is used to operate the work gate; the operation of the work gate and the movement of energy into storage both dissipate energy into the heat sink = Green plant: combination of work gate, cycling receptor, and self-maintenance; a work gate controls a cycling receptor, which delivers energy to a self-maintenance unit (the body of the plant); the work gate, the cycling receptor, and the self-maintenance unit all dissipate energy into the heat sink = Based on Howard T. Odum, Environment, Power, and Society, Wiley-Interscience, 1970

5. Birds Insects Birds of prey Rodents Sun Grass Bison Soil organisms Soil Dead grass

6. If skuas did ecology Penguin chicks Skuas Penguins

7. Skuas miss the larger picture Penguin chicks Skuas Some dependencies may not be obvious to the participants Penguins Leopard seals, etc. Fish Phytoplankton, algae Krill Sun Toothed whales Baleen whales

8. Various estuary animals Estuary plants Sun on upstream areas Sun on estuary Sediment-dwelling organisms Sediment Unused sediment

9. Simplified estuary Some of the energy in a system plays its role embodied in particular materials Elements, useful compounds Animals Plants Decomposers Carcasses, excrement Sun Detritus Potential long-term storage

10. Matter vs. energy Matter cycles around the ecosystem, with some loss and some gain from outside Energy doesn’t cycle—it passes through, supporting the organisms in the ecosystem and moving matter around

11. Prairie diagram Humans Like bears, humans eat from several levels of the food web Birds Insects Birds of prey Rodents Sun Grass Plants Bison Soil organisms Soil Dead grass

12. http://www.iarc.uaf.edu/highlights/2005/coupled_marine_ecosystem/index.phphttp://www.iarc.uaf.edu/highlights/2005/coupled_marine_ecosystem/index.php http://io.uwinnipeg.ca/~simmons/16cm05/1116/16ecosys.htm

13. Arctic diagram Tundra plants Humans Polar bears Carribou Wolves In the Arctic, humans eat mostly very high on the food web Ringed seals, etc. Fish Phytoplankton, algae Toothed whales Sun on ocean Sun on tundra Krill Baleen whales Climatic conditions shape the distribution of stored energy Human economies adapt to that

14. Porpoise growth elsewhere Weather Rain Trees Soil fertility Sun Plants

15. Porpoise growth elsewhere Fishing Boat building Boats Weather Rain Trees Soil fertility Sun Food People Plants Plant harvest

16. Porpoise growth elsewhere Fishing Boat building Boats Weather Trees Rain Soil fertility Sun Food People Plants Plant harvest

17. Weather Rain Soil fertility People Food Sun Plants Plant harvest

18. Animals Storage in soil Ecosystem without humans 10 Figure I.2.1 100 • Part of the energy used by plants and animals ends up improving the conditions for other plants to grow • Plant parts decay and become part of the soil • Animals “cultivate” the soil, spread seeds, contribute to humus formation • All energy put in ends up eventually in the heat sink • Except for possibly some additions to storage 50,000 1,000 90 Sun Plants 49,000 49,110 810 808 80 79 1 2

19. Birds of prey People Birds Insects Rodents Bison Grass Dead grass Soil organisms Soil

20. Small humans in ecosystem 10 Figure I.2.2 1 100 Humans • Humans siphon off a little bit of plant energy • Some displacement of animals (competitive exclusion) • Also siphon off a bit of animal energy • A little human activity may contribute to system maintenance 9 50,000 1,000 85 1 Sun Plants Animals 5 49,000 49,110 810 75 5

21. Birds of prey People Birds Insects Rodents Bison Grass Dead grass Soil organisms Soil

22. Birds of prey People Birds Insects Rodents Bison Crops Dead grass Soil organisms Soil

23. Simple agriculture 9 Figure I.2.3 7 35 2 Humans • Humans redirect resources to themselves • Lots of competitive exclusion • Need to replace more that plants do … … and animals work under human direction … (wild animals are replaced by domesticated ones) … so humans work a lot • The system doesn’t capture as much energy … … but there’s more for humans • Historically, storage is often drawn down 50,000 400 25 1 Sun 9 49,600 Plants 49,644 Animals 325 22 15

24. 2-field agriculture Field operations 22 Figure I.2.4 20 5 11 Soil improvement 15 25,000 200 Fallow 5 7 11 24,805 24,800 Animals 180 17 2 23 Sun 30 11 3 45 25,000 400 People Crop 24,600 24,628 325 28 Split the area into two fields (crop and fallow) Fallow collects energy and nutrients that are available to the crop when the fields are switched Animals contribute soil improvement, field work, and food

25. Agricultural progression • Humans restructure ecosystems to direct more captured energy to themselves • But they disrupt ecosystem functions, reduce total productivity • We increase our take by getting a much larger share of a smaller total • Improved farming partially replicates ecosystem functions with human and animal labor

26. Increase 1 9 7 7 35 Humans Humans 2 50,000 50,000 400 25 1 1 Sun Plants Plants Animals Animals 9 9 49,644 325 22 15 15 18 14 14 70 4 100,000 100,000 800 50 2 2 Sun 18 18 99,288 650 44 30 30 Increasing the energy input (e.g., drawing on a larger area of land) will increase what’s available to humans

27. Increase 2 Cows 40 40 5 5 Food 100,000 Farming system Sun Grains & veggies 25 More efficient processors leave more for us Chickens 35 35 7 7 100,000 Food Farming system Sun Grains & veggies 30

28. Increase 3 Less wasteful technology allows you to do more work 200 Falling water 20 20 180 180 Final product Farm, forest 10,000 10,000 100 100 70 Sun Mill Raw material (wood, wool, grain) 9,900 50 It may drive an increased draw on other resources 200 Falling water 40 40 160 160 Final product Farm, forest 20,000 20,000 200 140 200 Sun Mill Raw material (wood, wool, grain) 19,800 100

29. Means of expansion • For humans to have “more,” some combination of: • Restructure to take larger portion of what the system captures • Restructure so the system captures more • Larger input • More land, new source (e.g., falling water) • Better use of what you capture

30. Supply and demand • Relationships between price and: • Quantity people are willing to produce and sell • Supply • Quantity people are willing to buy • Demand

31. Demand Price Quantity • As the price falls, you give up less in order to buy a thing • Buy more at a lower price • Demand represented as a curve that slopes down to the right • Connects lower prices with larger quantities sought

32. Supply Price Quantity • As you produce more, must resort to more expensive inputs • Or less effective ones • Only willing to supply more if the price is higher • Supply curve slopes up to the right • Connects higher prices with larger quantities offered

33. Basic supply and demand Supply: a relationship between price and quantity people want to produce / sell Demand: a relationship between price and quantity people want to buy Price D S Equilibrium: where supply and demand meet, which tells you: 1. Price at which the market will clear P* Quantity Q* 2. Quantity that will be produced and bought

34. Basic supply and demand Price • Economic events move one or both curves • Tastes • Income • Prices of related goods • Policy • War • Innovation • New capital • Changes in resources D S P* Quantity Q*

35. P P Q Q Super-Prius Hummer What happens when the price of gas goes to $6/gallon? Demand for Hummers collapses Price (and profit) for Hummer maker falls Demand for Super-Prius (100 mpg) arguably increases Price (and profit) for Prius maker rises

36. Reallocation P DP DH QH QP Car-building capital Capital is reallocated from creation of Hummers to creation of Super-Priuses

37. Reading for Nov. 12, 16 • Hall, C.A.S., Day, J.W. Jr. 2009. “Revisiting the limits to growth after peak oil,” American Scientist 97:230-237 • http://www.esf.edu/efb/hall/2009-05Hall0327.pdf