1. Wetland Destruction
APES

2. What are Wetlands? Wetlands: Transitional lands between aquatic and
terrestrial ecosystems. Areas of land covered by
shallow water for at least part of the year.
Characteristics defined by:
Hydrology
Soils
Waterlogged
Anaerobic
Rich in organic material
Water-tolerant vegetation
Hydrophytes – plants that love water 3 types – submerged, emergent and floating

3. Fresh Water Wetlands Examples: Marshes Swamps Floodplains
Peat moss bogs
Prairie pot holes
Marshes = reeds, rushes and sedges have hollowed out stems to deliver oxygen
Swamps = buttressed shape trunks like bald cypress trees to provide support and oxygen support
Floating plants have waxy coated bottoms and pores on top to prevent constant water logging and facilitate O2 absorption
Specialized cells to facilitate transport of oxygen
Adventetious roots
knees that prop the roots above the water suface

4. Coastal Wetlands Mangrove Forests Salt Marshes
Cover 70% of tropical coastlines
Salt Marshes
Temperate Zones
Salt tolerant grasses
Storm buffer
Mangroves – Nutrient rich coastal zones – rapid nutrient cycling due to tidal flows. 69 different tree species that can grow in salt water.
Extensive root systems that extend above water – knees to obtain oxygen during high water levels
Nursery sites for juvenile species and protect coasts from erosion

5. Estuaries

6. Definition A coastal body of water, partly surrounded
by land, with access to the open ocean and a large
supply of fresh water. In other words… where
river meets sea.
High Productivity
Nutrient Input
Many producer plants
Tidal flow circulates nutrients rapidly
Shallow – sunlight penetration

7. Variable Environment Daily/Seasonal Variations in:
Salinity and Temperature:
Daily Tidal Cycle
Seasonal Flow of Streams (e.g. spring snow melt)
Storms (rain, hurricanes)
Seasonal Temperature Changes
Color of Substrate

9. Ecological Functions Recharge groundwater Reduce flood/storm damage
Trap/hold pollutants from fertilizers
Nitrates and phosphates
Wildlife Habitat/Nursery Sites

10. Critical Habitat Wetlands provide critical habitat for many species
listed as endangered or
threatened:
½ of all fish species
1/3 of all bird species
1/6 of all mammal species

11. Economic Benefits Fishing Peat moss
Blackberries, cranberries, blueberries
Recreational Benefits
Hunting
Boating
Bird watching
Photography

12. Environmental Threats
Construction of dams for flood control
Levees and Dikes
Channelization for flood control

13. Aerial view of the channelized system showing the canal (center) and spoil mound (left-center), drained floodplain (right), and remnant river channel (left). Note the oak tree line at the far left and right which marks the outer boundaries of the historic floodplain.

14. No flow conditions within remnant channels have allowed emergent and floating vegetation to choke the channel. Death and decay of this plant growth has resulted in thick accumulations of organic matter covering the historic sand substrate. The accumulated organic matter has increased biological oxygen demand within the channel, contributing to chronically low dissolved oxygen levels.

15. Environmental Threats Cont.
Drainage for:
Agriculture
Mosquito control
Filling for:
Residential/Industrial development
Solid waste disposal
Road building
Dredging for:
Transportation

16. The Results
In the US, wetlands have been shrinking by 58,500 acres per year since 1985.
Continental US – ½ of the original wetlands have been lost
Most of the loss has been the result of converting wetlands to croplands.

17. Clean Water Act
Section 404 of the Clean Water Act establishes a program to regulate the discharge of dredged and fill material into waters of the United States, including wetlands. Activities in waters of the United States that are regulated under this program include fills for development, water resource projects (such as dams and levees), infrastructure development (such as highways and airports), and conversion of wetlands to uplands for farming and forestry.

18. Section 404 Reasonably effective for coastal wetlands
Ineffective for inland wetlands (majority of America’s wetlands)

19. Response: Emergency Wetlands Resources Act - 1986
Authorized the FWS to inventory and map US wetlands. This facilitates:
Planning for drinking water supply protection
Siting of development projects
Floodplain planning
Endangered species recovery plans
90% of lower US has since been mapped

21. The Loophole or Solution?
Wetland Mitigation Banking:
Development of wetlands is allowed if a
corresponding amount of previously
converted wetlands is restored or new ones
are built.
Thus, No Net Loss of Wetlands

22. Wetland Restoration/Construction

24. Limitations of Mitigation Banking
Not all restorations are successful
No routine tracking of compliance
Lack of complete knowledge of wetland dynamics
75% of wetlands are privately owned
Conservation efforts are voluntary
Tax incentives
Wetlands Reserve Program (WRP) – Food Security Act -1985
Conservation easements

25. DOT’s Sweetwater Marsh San Diego Bay

26. Clapper Rail Marsh designed to provide habitat for the
clapper rail (ESA).
Design Flaw:
Marsh grass too short
Sediment dredged from shipping channel obtained from an old dump.
Too sandy to retain nitrogen