Ecological Systems Maintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure Projects

1. Ecological SystemsMaintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure ProjectsModule 3Impacts of Infrastructure

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

3. Learning Outcomes • Identify the ways in which infrastructure projects can cause habitat loss • Identify the ways in which pollution can harm ecosystems • Describe how discharges to ecosystems can disrupt ecological stability

4. Outline • Causes of Ecosystem Degradation • Impacts of Infrastructure Projects • Major Impacts in the United States • Major Impacts Globally

5. Ecosystem Degradation • Ecosystems are comprised of complex linkages between species and their environment • Damage can cause cascading impacts throughout the ecosystem • Ecological damage can be caused by local or non-local activities

6. Types of Ecosystem Degradation • Direct loss of habitat due to development • Damage resulting from human use and/or discharges • Decline in one or more species • Degradation or collapse of food webs • Loss of ecosystem function

7. Causes of Ecological Damage • Direct habitat loss • Habitat fragmentation • Damage to physical environment • Chemical toxicity • Hunting and harvesting • Introduction of exotic species • Disease and insect infestations

8. Direct Habitat Loss • Loss of habitat due to conversion of land from one use to another • Development of land for housing, agriculture, mining, or other uses • Loss of habitat eliminates locations where species and ecosystems can be found

9. Habitat Fragmentation • Loss of connection between habitat areas • Roadways and other man-made obstacles prevent movement between habitat areas • Animals are unable to migrate in response to changes in weather or food supply • Young animals cannot disperse to find new home ranges • Genetic resources become isolated

10. Damage to Physical Environment • Man-made and/or natural disturbances damage essential physical features of the environment • Physical features can be damaged by erosion, sediment deposition, changes to hydrology, fire • Damaging critical resources, such as shelter and access to fresh water, limits the population sizes that can be supported by the environment • Noise and light pollution can create barriers to movement, disrupt migration patterns, inhibit reproduction, and cause stress

11. Chemical Toxicity • Chemicals are discharged or deposited within the environment • Chemicals cause illness and/or death of individuals, limiting population sizes • May have secondary impacts on other species within the ecosystem, for example loss of food supply

12. Hunting and Harvesting • Humans directly suppress population sizes through hunting and harvesting • Over-harvesting may reduce population sizes beyond a critical threshold, causing collapse • Secondary impacts may be felt on other species dependent on the target species • Hunting and harvesting may cause physical damage to the environment

13. Introduction of Exotic Species • Species not native to the ecosystem may be introduced intentionally or unintentionally • Some exotic species may thrive due to absence of natural predators • Successful exotic species may outcompete native species for resources • Result is loss of native biodiversity, ecological function

14. Disease and Insect Infestations • Disease or insect population explodes in an ecosystem, causing damage • Can be caused by natural cycles, loss of ecological balance, and/or introduction of exotic diseases and pests • Can cause illness or death directly or indirectly by killing off or consuming a critical food source

15. Examples • Eutrophication • Loss of top predators • Loss of the base of the food chain • Stream degradation • Xenobiotic contamination xenobiotic: foreign or man-made chemicals

16. Eutrophication Overuse of fertilizers in landscaping and agriculture Inadequate sewage treatment Discharge of nitrogen and phosphorus Overgrowth of algae Death of algae Overgrowth of bacteria Oxygen depletion Fish kills

17. Eutrophication

18. Eutrophication EPA

19. Loss of Top Predators X Hunting Habitat fragmentation Loss of wolves X Deer become overpopulated Plants are overgrazed XXX Deer population crashes

20. Loss of the Base of the Food Chain Fossil fuel consumption Deforestation Global climate change Loss of Antarctic sea ice Expansion of krill fisheries Decline in krill population Decline in penguin populations

21. Stream Degradation Roads Buildings and parking lots Lawns Agricultural fields Fertilizer Increased stormwater runoff Pesticides Increased temperature Habitat destruction Heavy metals Eutrophication Loss of invertebrates Loss of fish

22. Xenobiotic Contamination (PCBs) PCBs in transformers and capacitors Spillage and leaks Migration into groundwater Leaching into waterbodies Buildup in sediments Bioaccumulation in invertebrates Bioaccumulation in fish Bioaccumulation in humans Cancers, damage to skin, stomach, liver, kidneys, thyroid, nervous system

23. Types of Pollutants • Directly harmful • Heavy Metals • Xenobiotic compounds (man-made) • Indirectly harmful • Nutrients • CO2 • Organic matter

24. Directly Harmful Pollutants • Cause illness or mortality through ingestion, inhalation, and dermal absorption • Are not “naturally” present, or naturally occur in minute quantities (with exceptions)

25. Indirectly Harmful Pollutants • Are not directly toxic • Normal flows are necessary for ecosystem function • Elevated flows cause ecosystem imbalance and cascading negative effects

26. Course Outline • Causes of Ecosystem Degradation • Impacts of Infrastructure Projects • Major Impacts in the United States • Major Impacts Globally

27. Infrastructure-Specific Impacts • Roads • Sprawl • Stormwater runoff • Wastewater treatment • Mining • Dams • Navigation projects • Power generation • Agriculture

28. Local Impacts of Roads • Habitat fragmentation • Road kills • Impedes migration and dispersal FHWA

29. Impacts of Sprawl • Habitat loss and fragmentation • Introduction of invasive species • Increased driving leads to increased CO2 • Increased stormwater runoff, including lawn chemicals (fertilizers and pesticides) NASA

30. Impacts of Stormwater Runoff • Hydromodification • Loss of habitat features (in-stream shelter, deep pools, base flow) • Elevated water temperature • Eutrophication USGS

31. Impacts of Wastewater Treatment Discharges • Eutrophication • Elevated temperatures • Xenobiotics USGS

32. Impacts of Mining and Extraction • Habitat loss • Contamination due to leaching from spoils • Groundwater contamination EPA

33. Impacts of Dams • Habitat loss • Altered hydrology • Reduced sediment flows downstream • Habitat fragmentation USACE

34. Impacts of Navigation Projects • Loss of river and estuary bottom habitat • Estuary sediment starvation • Wetland subsidence USGS

35. Impacts of Power Generation • Local: • Elevated water temperature • Habitat fragmentation due to transmission corridors • Contamination due to accidental chemical release • Non-local: • Air pollution • Climate change • Impacts of extraction USGS

36. Course Outline • Causes of Ecosystem Degradation • Impacts of Infrastructure Projects • Major Impacts in the United States • Major Impacts Globally

37. Impacts in the United States • Habitat loss and fragmentation • Depletion of fresh water resources • Eutrophication • Coastal Louisiana wetland loss • Hydromodification

38. Habitat Loss • 60% of the US (outside Alaska) has lost its natural vegetation • 53% of wetlands in the lower 48 states have been lost • Habitat destruction is the leading threat to US species • Flyways used by migrating waterfowl are threatened • Sprawl is a major cause of destruction TJ Watt / Wikimedia Commons / CC-BY-SA-3.0

39. Habitat Fragmentation • Sprawl and unplanned growth contribute to habitat fragmentation • Fragmentation isolates populations, limiting migration, dispersal, and genetic exchange • Fragmentation eliminates habitat for animals with large home ranges USGS

40. Depletion of Water Resources • Freshwater availability is becoming a serious issue, especially in western states • Rapid population growth puts pressure on water supplies • Climate change reduces mountain snowpack, reducing stream flows • Changes in surface waters and shallow groundwater disrupt ecological function NOAA

41. Eutrophication • Caused by excess nutrient discharges (nitrogen and phosphorus) • Major cause of coastal hypoxia • Mississippi Gulf • Chesapeake Bay NASA

42. Coastal Louisiana Wetland Loss • Subsidence resulting from natural sediment compaction is no longer balanced by inflowing sediment from upstream • Subsidence combines with sea level rise to create water depths too deep to support marsh grass • Marsh grass dies off, resulting in erosion and permanent marsh loss State of Louisiana

43. Hydromodification • Development increases watershed imperviousness, which causes increased storm flows • High peak flows erode stream banks, altering stream morphology and destroying habitat Ken Andrews

44. Course Outline • Causes of Ecosystem Degradation • Impacts of Infrastructure Projects • Major Impacts in the United States • Major Impacts Globally

45. Global Impacts • Depletion of fresh water resources • Climate change • Excessive nutrient loading • Loss of biodiversity • Habitat loss

46. Loss of Fresh Water • Overuse for irrigation • Discharge to oceans USGS/ Woods Hole Oceanographic Institute

47. Climate Change • Caused by increasing atmospheric CO2 and CH4 • Power generation using coal, oil, and gas • Reliance on gasoline-powered vehicles • Deforestation • Methane emissions from landfills NASA

48. Excessive Nutrient Loading • Primarily the result of increasing use of fertilizers in agriculture and landscaping

49. Loss of Biodiversity • Rate of extinctions in the last century is 50-500 times greater than the background rate • Primarily caused by habitat loss

50. Habitat Loss • Deforestation for agriculture • Desertification, loss of polar habitat, coral bleaching resulting from climate change Millennium Ecosystem Assessment