Obion Creek and Bayou de Chien drain approximately 350,000 acres of predominantly agricultural lands in western Graves County, southern Carlisle County and most of Hickman and Fulton counties in southwestern Kentucky. The two streams join about two miles east of the Mississippi River before flowing into it. Roughly a tenth of their watersheds lies in the Mississippi's alluvial plain, and the remainder is part of the Upper East Gulf Coastal Plain ecoregion. The Nature Conservancy has designated the two watersheds a priority conservation site.
The Conservancy has long been at work in the area. About four decades ago, the organization acquired the 175-acre Murphy's Pond tract of what is now the 1,577-acre Obion Creek State Nature Preserve in Hickman County. In 1992, the Conservancy assisted the Kentucky State Nature Preserves Commission in acquiring 1,402 acres for the preserve, which protects wetland communities such as shrub swamp, marsh and bottomland hardwood forest as well as upland slopes. Species recorded at Murphy's Pond, an old oxbow of Obion Creek, include 45 mammals, 40 reptiles, 30 amphibians and more than 200 birds.
Also under public ownership within the watersheds is the state's 3,521-acre Obion Creek Wildlife Management Area. It includes the Letourneau Woods—870 acres of old-growth hardwood forest—and it hosts large populations of wintering waterfowl, nesting cerulean, prothonotary and Swainson's warblers, and other neotropical songbirds.
The Obion Creek and Bayou de Chien watersheds have undergone substantial deforestation, changes in land use and stream channelizations that have contributed to an extensive alteration of the aquatic habitat in the two streams and their smaller tributaries. Increased sedimentation and contaminants, as well as altered flow velocities, are among the ecological stresses facing aquatic species. The loss of suitable vegetation buffers along streams has increased water temperatures and reduced necessary corridors connecting wild habitats.
The Conservancy is working with local conservation organizations and private landowners to identify specific target areas for conservation action within the two watersheds. It is also seeking to reestablish bottomland hardwood forests, wetlands and streamside vegetation. In partnership with the Kentucky Department of Fish and Wildlife Resources and the Kentucky State Nature Preserves Commission, the Conservancy is promoting and assisting participation by private landowners in incentive-based conservation programs such as the federal Wetlands Reserve Program.
The Obion Creek and Bayou de Chien watersheds provide important habitat for a variety of plants and animals, but for one fish species in the Bayou de Chien watershed conservation efforts are a matter of life or extinction. The relict darter, listed as endangered by the U.S. Fish and Wildlife Service after its population declined to critically low numbers between the 1970s and early 1990s, is known to exist nowhere else on Earth.January 26, 2011