Multispecies and Watershed Approaches to Freshwater Fish Conservation

Abstract.—There are more than 2.4 million stream km found in the southeastern states that intersect nearly 30 different ecoregions before draining into the Atlantic Ocean or Gulf of Mexico. These streams host one of the greatest diversities of aquatic organisms on earth. In fact, southeastern streams contain more at-risk fish and aquatic invertebrate species than any other region in the United States, containing almost two-thirds of the nation’s fish species, more than 90% of the nation’s mussel species, and nearly half of the global diversity in crayfish species. Many of these species are endemic to specific drainages and found nowhere else in the world. This level of diversity and endemism increases the sensitivity of these systems to stressors, thus partially explaining the 2–4% annual declines since 1950s. Major threats to aquatic ecosystems in southeastern U.S. streams can be grouped together into interacting categories: land-use changes, incompatible land management practices, nonnative species invasions, habitat fragmentation, flow modifications, and overallocation of water. The Southeast Aquatic Resources Partnership is working across the geography to quantify the degree of fragmentation from both dams and culverts across the landscape and identify opportunities to reconnect rivers and streams through actionable science and effective partnerships.