The NWI is a system to identify and classify the nation's wetlands using high-altitude, infrared photography. The Federal Duck Stamp program is a way the public can preserve wetlands.
Wetlands occur when a water table is at, or near, the surface or when land is covered by shallow water. It's essential habitat for ducks, geese, shore and wading birds, fish, frogs, deer, pheasants and others.
"Acre for acre, wetlands support more animals and plant life than any other biological community on the earth," said Chuck Elliott, Regional Wetland Coordinator for the U.S. Fish and Wildlife Service. Wetlands also provide water for irrigation, for municipal and industrial water supplies and for groundwater recharge. Wetlands can help deter floods by storing water and preventing large amounts of runoff. They also trap chemical runoff.
But the United States is in danger of losing this valuable resource. Over a period of 200 years - from the 1780's to the 1980's - the U.S. Fish and Wildlife Service estimates that the lower 48 states lost more than 53 percent of their original wetlands. This means the lower 48 states have lost more than 60 acres of wetlands for every hour between the 1780's and the 1980's, with most of the loss occurring in the midwest, Elliott said.
In the past, people have had a negative view of wetlands and many have been destroyed. Numerous wetlands were drained and converted to farmland, filled for new development, and used as receptacles for household and hazardous waste.
A national wetland trend study showed that agriculture was responsible for 87 percent of the wetland loss that occurred throughout the United States during the 20-year period from the mid-1950s to the mid-70s, Elliott said. With wetlands rapidly being exhausted, the Service wanted to concentrate on conservation efforts. Before that could be done, biologists needed to determine how many wetlands existed and what kind of wetland they were.
"It's such a valuable resource," Elliott said. "If the government is going to manage it well on the public's behalf, we need to know where they are, what kinds are there, and how many there are."
As a result, the National Wetland Inventory was born. The Service uses aerial photography to create maps that will establish a file of all the wetlands in the United States. Photographs are shot by U-2 aircraft flown by the National Aeronautics and Space Administration and by Lear jets from the National High Altitude Program. Both sources produce color infrared photographs at a scale of approximately 1:60,000, Elliott said.
Inventory biologists and photo interpreters take the photos into the field and compare them to the actual landscape. Photointerpreters use a stereoscope to view the landscapes in detail. Maps are reviewed and the information is transferred to a base map. They are reviewed once more in the field. Finally, the maps are printed and digitized on computers to be distributed to the public.
"Basically it's just data collection, it's a resource available for other agencies and the public to make more educated decisions," Elliott said. The Service is mandated by Congress to complete the inventory by 1998. To obtain more information about the maps, call 1-800-USA-MAPS.
While the wetlands inventory is a way to document the "big picture" on how many, and what kind of wetlands exist, the Migratory Bird Hunting and Conservation Stamp, also known as the Federal Duck Stamp, is "the little picture." And it's the public's most direct route to help preserve wetlands.
The stamp, with its unique artwork, is available for $15. Most of the stamps are purchased by waterfowl hunters because it's mandatory they have one before venturing out into the field. But more non-hunters are purchasing the stamp as a direct way to help preserve precious wetland habitat. Since its inception 50 years ago, more than $300 million has been raised for the conservation of wetlands. Stamp proceeds have helped buy a significant portion of the nation's 500 wildlife refuges. Now many states have emulated the Service and issue their own stamp.
"One reason the Federal Duck Stamp is so valuable is that it provided the lead for states to follow, and now about 47 states have a stamp," Elliott said.
Federal Duck Stamps can be purchased at most post offices, national wildlife refuges and stamp shows.
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