This Wednesday, March 23, 11:45-12:30 in Phelps Lab, Room 101:

Role of Hydrologic Connectivity to Conservation of Aquatic Biodiversity in the Apalachicola-Chattahoochee-Flint (ACF) basin
Stephen J. Walsh, PhD
U.S. Geological Survey, Gainesville, FL

By discharge, the Apalachicola-Chattahoochee-Flint (ACF) river basin is the fourth largest in the Southeast and the 21st largest in the coterminous U.S. The basin supports a diverse aquatic fauna that has historically been degraded by years of flow regulation, land-use changes, and long-term droughts. Many threats to the aquatic fauna involve alterations in hydrologic connectivity, defined as the water-mediated transfer of matter, energy, and organisms within or between elements of the hydrologic cycle. The dimensions of fluvial connectivity vary spatially and temporally, and alterations to connectivity affect the aquatic biota differentially depending on location and intra- and inter-annual hydrologic fluctuations. Disruptions to longitudinal and lateral connectivity in headwaters results in habitat fragmentation, loss of population linkages, and local extirpation. Changes to main-channel connectivity, primarily in the form of dams, has converted lotic habitats to lentic habitats, blocked movement of migratory species, affected water quality and biogeochemical cycling, and has resulted in changes to community structure. In the lower reach of the system, the Apalachicola River has been altered by a combination of spatial and temporal disruptions in lateral connectivity and hydrologic pulses that link the extensive floodplain and main channel. Examples of these principals, based on evaluations of fish populations, provide a basis for the need to re-establish hydrologic connectivity and natural flows in order to restore and conserve the native biota. The issue of water allocation within the basin presents a unique challenge of how to balance human needs with the restoration and protection of biodiversity.

Seminar series website with schedule and recordings for Spring 2011 and past semesters:

Sharlynn Sweeney, PhD
Center for Environmental Policy and
H.T. Odum Center for Wetlands
University of Florida