Wetlands

Aquatic Habitats

Aquatic Food Webs

Aquatic Food Webs [Image: US EPA]

Aquatic food webs are conceptual diagrams that demonstrate the flow of energy and nutrients in aquatic systems. Although the species that make up aquatic food webs will greatly vary depending on habitat type, the basic trophic levels or feeding levels of food webs are similar. Producers such as phytoplankton, aquatic plants, and algae use photosynthesis to convert sunlight and nutrients into living tissue. Primary consumers such as zooplankton and plant grazers eat producers. Secondary and tertiary consumers such as invertebrate predators, birds, fish, mammals, and humans eat lower-level prey items. Decomposers consume dead plants and animals, breaking organic matter down into nutrients. Since organisms seldom feed exclusively on another, several food chains are often woven together to form a "food web," a complex cycle of interconnected organisms and organic matter.

Explore the NBII Fisheries and Aquatic Resources Node's Aquatic Organisms section for more information about the wide variety of organisms that use the aquatic environment, ranging from endangered species to aquaculture.

Discover the NBII Bird Conservation Node's U.S. Fish and Wildlife Service Focal Bird Species, many of which are shorebirds, seabirds, and waterfowl that are important components of aquatic food webs.

The Clean Water Act

EPA logo [Image: U.S. Environmental Protection Agency]

"The objective of the Federal Water Pollution Control Act, commonly referred to as the Clean Water Act (CWA), is to restore and maintain the chemical, physical, and biological integrity of the nation's waters by preventing point and nonpoint pollution sources, providing assistance to publicly owned treatment works for the improvement of wastewater treatment, and maintaining the integrity of wetlands." Visit the US EPA Clean Water Act website for detailed information about the Clean Water Act, including Total Maximum Daily Loads (TMDLs), point and non-point source pollution measures, wetlands regulations, estuary regulations, and more.

Wetlands

[Photo: Delaware Department of Fish and Wildlife]

Wetlands perform a key role in the global hydrologic cycle. The US Environmental Protection Agency (EPA) defines wetlands as "those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs and similar areas." Wetlands are highly variable, depending on the environmental conditions where they are found. They exist on every continent, from the tropics to the tundra, except for Antarctica.

Why we need wetlands

Wetlands provide an invaluable habitat for wildlife, and are among the most productive ecosystems in the world. They are an excellent habitat for primary producers that create the base of the food web, which in turn supports commercial fish and shellfish communities in coastal areas. Wetlands are not only great recreational areas, but also have many beneficial ecological functions, and are therefore referred to as "nature's kidneys". Overall water quality in freshwater and coastal systems is improved by wetlands because the slowed water in these areas allows sediment and excess nutrients to settle out. The wetland vegetation then uses the excess nutrients, and immobilizes some pollutants. During large storms and snow melt, wetlands also act to reduce flood height and recharge ground water slowly, thereby decreasing the economic risk associated with flood damage.

Sources:
Cech, T. 2005. Principles of Water Resources, Second Edition. John Wiley and Sons. Hoboken, NJ.
EPA Wetlands Page

To find out more about wetlands including their classification, habitats, and human impacts, follow the links below:

	Classification Learn about how wetlands are classified.
	Human Impacts (Accessible soon) Find out about how human activities can affect wetland habitats.
	Wetland Habitats Learn about the types of habitats within wetlands.

Discover the National Fish Habitat Action Plan and Data

NFHAP logo [Image: National Fish Habitat Action Plan]
[Image: National Fish Habitat Action Plan]

The National Fish Habitat Action Plan (NFHAP) is an unprecedented attempt to address a nationwide fish crisis by focusing on the loss and degradation of their habitat. The Plan was born in 2001 by an ad hoc group supported by the Sport Fishing and Boating Partnership Council. This group was inspired to develop a partnership effort for fish conservation in the image of the successful and strategic North American Waterfowl Management Plan.

As a federal-level partner, the USGS-NBII was designated by the National Fish Habitat Board to house the data delivery system supporting the National Fish Habitat Action Plan. Find out more about NBII's role in the NFHAP and the data associated with the Plan.

Wetland Loss in the U.S.

States with notable wetland loss, 1780s to mid-1980 [Image: USGS, modified from Dahl 1990]

Wetlands have been in decline in the U.S. since European settlement, with an estimated 100 million acres of wetlands lost since the late 1700s. Efforts to reverse the loss of wetlands since the 1980s have been positive, with the net loss decreasing from nearly 500,000 acres per year between the 1950s and 1970 to a net gain between 1998 and 2004. However, wetlands continue to be threatened by urban and rural development, habitat fragmentation, invasive species, global climate change, sea level chances, and hydrologic alterations.

Hawaii's Wetlands

Kealia East Pond in Maui, Hawaii [Photo: USFWS]

The NBII Pacific Basin Information Node (PBIN) is a gateway to biodiversity information for Hawaii and the Pacific Basin. PBIN provides access to information about Hawaii's wetlands, including two partnership efforts to protect, restore, and enhance wetlands: the Hawaii Wetland Joint Venture and the Pacific Coast Joint Venture.

Featured Resource

[Image: US EPA]

The U.S. Environmental Protection Agency's Office of Wetlands, Oceans, and Watersheds (OWOW) is a division within the Office of Water. The OWOW provides detailed information about our nation's wetlands, including definitions, types, status, ecosystem functions, and protection efforts.

Featured Resource

USFWS Wetlands Mapper Interface [Image: USFWS]

The U.S. Fish and Wildlife Service National Wetlands Inventory program has released a new wetlands mapper. This resource features up-to-date geographic information about wetland size, location, and type, in an interactive mapping format. The data is available for download and can also be viewed using Google Earth.

The NBII Program is administered by the Biological Informatics Program of the U.S. Geological Survey

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