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Ecological Systems Maintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure Projects Module 2 Introduction to Ecology. Emily Mitchell Ayers, Ph.D . The Low Impact Development Center, Inc. emayers@lowimpactdevelopment.org. Learning Outcomes.
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Ecological SystemsMaintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure ProjectsModule 2Introduction to Ecology
Emily Mitchell Ayers, Ph.D. The Low Impact Development Center, Inc. emayers@lowimpactdevelopment.org
Learning Outcomes • Understand what an ecosystem is • Learn how ecosystems function • Learn how ecosystems change over time 2-3
Outline • What Is An Ecosystem? • Ecosystem Structure • Flow of Energy and Materials Through Ecosystems • Ecosystem Stability • Succession 2-4
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
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
Types of Ecosystems Human-dominated • Urban • Suburban • Managed • Agriculture • Aquaculture • Constructed wetlands 2-7
Tropical Rainforest 2-8 Kat555 / Wikimedia Commons / CC-BY-SA-3.0
Savanna 2-9 Ikiwaner / Wikimedia Commons / CC-BY-SA-3.0
Desert 2-10 FWS
Chaparral 2-11 NPS
Prairie 2-12 DOI
Temperate Deciduous Forest 2-13 FWS
Coniferous Forest Maine Department of Conservation 2-14
Tundra FWS 2-15
Lakes and Ponds 2-16 FWS
Rivers and Streams 2-17 FWS
Freshwater Marshes 2-18 FWS
Bogs FWS 2-19
Swamps NRCS 2-20
Sand Dunes 2-21 FWS
Continental Shelf 2-22 USGS
Salt Marshes FWS 2-23
Cropland 2-24 NRCS
Pasture 2-25 NRCS
Aquaculture 2-26 NOAA
Constructed Wetlands Emily Ayers 2-27
Bioretention Emily Ayers 2-28
Urban Ecosystems NY DEC 2-29
Suburban Ecosystems 2-30 NYDOT
Outline • What Is An Ecosystem? • Ecosystem Structure • Flow of Energy and Materials Through Ecosystems • Ecosystem Stability • Succession 2-31
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
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
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
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
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
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
Food Webs Ecosystem structure is often described in terms of food webs, which diagram some of the relationships between species 2-40
Decomposers Trophic Structure 2-41
Chesapeake Bay Food Web 2-42 USGS
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
Example - Production Phytoplankton • Principal autotrophs in ocean ecosystems • Base of the entire ocean food web NOAA 2-44
Example - Consumption American bison • Prairie • Historically, bison were the principal herbivores • Grazing pressure maintained dominance of prairie grasses USDA 2-45
Example - Structure Marsh grass • Salt marshes • Shelters invertebrates, juvenile fish, amphibians • Prevents erosion • Loss causes subsidence, disappearance of marsh USDA 2-46
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
Outline • What Is An Ecosystem? • Ecosystem Structure • Flow of Energy and Materials Through Ecosystems • Ecosystem Stability and Resilience • Succession 2-48
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
Hydrologic Cycle 2-50