The Black River begins in southeastern Missouri near Taum Sauk Mountain, the state's highest point. Flowing generally southward, the river’s gradient, meander pattern and other characteristics change dramatically as it descends from the Ozark Plateau onto the Mississippi River's alluvial plain near Poplar Bluff, Missouri. The lower Black River extends from that descent to its confluence with the White River at Jacksonport, Arkansas.
The lower Black is typical of floodplain rivers that provide ideal conditions for bottomland hardwood forests where unique assemblages of plants and animals flourish. In such areas, cypress-tupelo swamps provide both conservation and aesthetic values. The Nature Conservancy has designated approximately 146,000 acres along the lower Black as a priority conservation site.
Historically, the Black River sustained phenomenal aggregations of mussels. As early as 1897, it was found to contain sufficient quantities of such species to sustain a local button-manufacturing industry, which operated from 1900 until plastic buttons were developed in the 1940s. Protection and restoration of the lower Black River and its basin is expected to contribute to the conservation of globally rare mussel species.
The Conservancy is in the initial stages of applying a science-based process to identify specific environmental stresses in the lower Black River basin. However, such stresses are expected to include ecological factors generally occurring elsewhere within the Mississippi River's alluvial plain, such as altered water flows, fragmented and altered habitats and reduced water quality.