Wetland Destruction APES

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

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

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

Estuaries

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

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

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

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

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

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

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.

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.

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

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.

Clean Water Act - 1972 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.

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

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

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

Wetland Restoration/Construction

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

DOT’s Sweetwater Marsh San Diego Bay

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