An Aquatic Gap program is underway for the riverine and coastal systems of the Great Lakes region. The Great Lakes are the largest system of fresh water on earth and provide habitat for a wide variety of aquatic organisms unique to these systems. The aquatic biodiversity of the region is being threatened due to urban expansion, more intensive agricultural practices, continued logging, coastal zone shoreline destruction, and other human activities.
Gap Analysis is a scientific means for assessing to what extent native animal and plant species are being protected. The goal of the US Geological Survey's (USGS) Gap Analysis Program (GAP) is to keep common species common by identifying those species and communities not adequately protected in existing conservation lands. Scientists, land managers, and policy makers can use this information to make better-informed decisions when identifying priority areas for conservation. Gap Analysis came out of the realization that a species-by-species approach to conservation is not effective because it does not address the continual loss and fragmentation of natural landscapes. Only by protecting regions already rich in habitat can we adequately protect the animal species that inhabit them.
In 2001, the USGS, in cooperation with several state natural resource-management agencies, began a regional Aquatic Gap project in the Great Lakes Basin focusing on the distribution of aquatic species in riverine and coastal habitats. This project was undertaken for several reasons. The Great Lakes basin is a globally unique, geographically distinct, and biologically rich region encompassing 196,250 square miles in the United States (U.S.) and Canada. It contains over 11,000 miles of coastline, a large concentration of wetlands, diverse forests, hundreds of tributary streams, and about 18% of the Earth's fresh surface water (USEPA and Government of Canada, 1995). Over 300 species of fish and many other aquatic organisms inhabit the rivers, streams, and coastal habitats of the Great Lakes Basin throughout critical life history stages (Greeley 1940, Jude and Pappas 1992).
Preservation of biological diversity is a regional priority because of its strong connection to the economy, the health of the surrounding human population, and wildlife resources through transportation, tourism, recreation, fisheries, and water use for human needs and ecosystem function. In 1996, two million anglers fished the Great Lakes, adding more than $1 billion (U.S.) to the regional economy, and the commercial fish harvest of 63 million pounds brought in more than $43 million (Michigan Sea Grant, 2000).
Despite the value of these water resources, the aquatic biodiversity of the Great Lakes region is threatened due to a number of physical and chemical changes in the environment. Factors such as changing land use patterns, development, pollution from point and non-point sources, dams, and invasion of exotic species have reduced the availability of aquatic habitat and access to historical fish-spawning grounds and nurseries.
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