Emily Mitchell Ayers, Ph.D .

1. Ecological SystemsMaintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure ProjectsModule 2Introduction to Ecology

2. Emily Mitchell Ayers, Ph.D. The Low Impact Development Center, Inc. emayers@lowimpactdevelopment.org

3. Learning Outcomes • Understand what an ecosystem is • Learn how ecosystems function • Learn how ecosystems change over time 2-3

4. Outline • What Is An Ecosystem? • Ecosystem Structure • Flow of Energy and Materials Through Ecosystems • Ecosystem Stability • Succession 2-4

5. What Is An Ecosystem? • An ecosystemis a unit that consists of living and non-living components interacting to form a system • Ecosystems are almost always open systems with inputs and outputs 2-5

6. Types of Ecosystems Natural • Terrestrial • Forested • Grass/shrubland • Desert • Ice/Snow • Freshwater • Lakes and ponds • Rivers and streams • Wetlands • Marine • Estuaries • Near-shore • Deep ocean 2-6

7. Types of Ecosystems Human-dominated • Urban • Suburban • Managed • Agriculture • Aquaculture • Constructed wetlands 2-7

8. Tropical Rainforest 2-8 Kat555 / Wikimedia Commons / CC-BY-SA-3.0

9. Savanna 2-9 Ikiwaner / Wikimedia Commons / CC-BY-SA-3.0

10. Desert 2-10 FWS

11. Chaparral 2-11 NPS

12. Prairie 2-12 DOI

13. Temperate Deciduous Forest 2-13 FWS

14. Coniferous Forest Maine Department of Conservation 2-14

15. Tundra FWS 2-15

16. Lakes and Ponds 2-16 FWS

17. Rivers and Streams 2-17 FWS

18. Freshwater Marshes 2-18 FWS

19. Bogs FWS 2-19

20. Swamps NRCS 2-20

21. Sand Dunes 2-21 FWS

22. Continental Shelf 2-22 USGS

23. Salt Marshes FWS 2-23

24. Cropland 2-24 NRCS

25. Pasture 2-25 NRCS

26. Aquaculture 2-26 NOAA

27. Constructed Wetlands Emily Ayers 2-27

28. Bioretention Emily Ayers 2-28

29. Urban Ecosystems NY DEC 2-29

30. Suburban Ecosystems 2-30 NYDOT

31. Outline • What Is An Ecosystem? • Ecosystem Structure • Flow of Energy and Materials Through Ecosystems • Ecosystem Stability • Succession 2-31

32. Ecosystem Organization 2-32

33. Terminology • Population: A group of individuals of one kind of organism • Community: All populations occupying a given area • Ecosystem: A community and its natural environment • Biome: A large regional system characterized by a specific type of vegetation • Ecosphere: All of the living organisms on Earth, interacting with the physical environment 2-33

34. How Ecosystems Are Represented Ecosystems are described by diagramming interactions between components The model must consider: • The system boundary • System components • Inflows and outflows • Interactions 2-34

35. Diagram of An Ecosystem 2-35

36. Example – Freshwater Marsh • Dominated by emergent plants • Standing water for all or part of the year • Water flows into and out of the system • Nutrients flow into and out of the system • High capacity to remove nutrients from the water • Critical breeding ground for fish, birds, reptiles, amphibians • Often found at the interface of a water body and the land Maine DEP 2-36

37. How Do Ecosystems Work? • Animal, plant, and bacterial species are organized into a system that makes maximal use of the energy and materials flowing into the system • Each species inhabits a unique ecological niche, and plays a role in maintaining the system 2-37

38. Habitat • Habitat: the physical place where an organism lives (think “address”) • For animals, this usually includes the plant community • Examples: • Rocky outcrops • Shallow water • Vernal pools • Treetops • Caves 2-38

39. Niche • Niche: the role the organism plays in the ecosystem (“think profession”) • Examples: • Wolf: Predator of herbivores • Mycorrhizal fungi: symbiotic relationship with tree roots; fungus feeds on root exudates, and facilitates root uptake of nutrients 2-39

40. Food Webs Ecosystem structure is often described in terms of food webs, which diagram some of the relationships between species 2-40

41. Decomposers Trophic Structure 2-41

42. Chesapeake Bay Food Web 2-42 USGS

43. Keystone Species • Species (or groups of similar species) which serve a unique, essential function in an ecosystem • No other species serve a similar function • Loss can cause ecosystem collapse • Function can be production, consumption, structural, or nutrient cycling 2-42

44. Example - Production Phytoplankton • Principal autotrophs in ocean ecosystems • Base of the entire ocean food web NOAA 2-44

45. Example - Consumption American bison • Prairie • Historically, bison were the principal herbivores • Grazing pressure maintained dominance of prairie grasses USDA 2-45

46. Example - Structure Marsh grass • Salt marshes • Shelters invertebrates, juvenile fish, amphibians • Prevents erosion • Loss causes subsidence, disappearance of marsh USDA 2-46

47. Example – Nutrient Cycling Nitrosomonas and Nitrobacter bacteria • Present in aerobic soils and water • Responsible for nitrification (conversion of ammonia to nitrate) • Make nitrogen available to plants NASA 2-47

48. Outline • What Is An Ecosystem? • Ecosystem Structure • Flow of Energy and Materials Through Ecosystems • Ecosystem Stability and Resilience • Succession 2-48

49. Biogeochemical Cycles Materials are continually cycled within and between ecosystems. This cycling conserves essential resources, and maintains conditions necessary for life on this planet. 2-49

50. Hydrologic Cycle 2-50