BIOLOGICAL IMPACTS OF HURRICANE KATRINA ON THE GULF COAST

With more than two decades of hurricane-related experience, the USGS National Wetlands Research Center immediately responded to Hurricane Katrina by using specialized technology, aircraft and vessels. Scientists at NWRC assisted in post-Katrina boat rescues and humanitarian relief, geospatial database and map production for emergency response, and aerial reconnaissance and ground surveys of coastal impacts. The social and biological landscapes were severely damaged over a multi-state region by wind, surge and flood. Post-Katrina overflights and satellite imagery showed that marshlands and barrier islands east of New Orleans and the Mississippi River were severely scoured by Katrina's surge, further reducing their buffering capacity to protect coastal communities from future storm surges. Forest resources, particularly hardwoods, within the high-wind swath of Katrina suffered major blowdowns of canopy trees and leaf and branch stripping of standing survivors. The newly open canopies are expected to stimulate regeneration of the invasive tree species Chinese tallow and increase its dominance, thus reducing wildlife habitat quality of these coastal forests. Doppler-radar imagery of migratory bird movements before and after Katrina showed a dramatic shift in habitat use away from coastal wind-ravaged hardwood forests to more inland and low-impact pine forests. Radar monitoring of bird density patterns will continue through fall migration to determine the implications of wide-area destruction of prime staging habitat on transgulf migration patterns and survivorship. By using NWRC's advanced spatial databases and hurricane modeling tools, field studies in forest, marsh, and seagrass habitats will be conducted to relate storm forces to landscape-scale patterns and processes of habitat alteration. Post-Katrina studies are expected to advance current knowledge about the role wetlands play in mitigating storm impacts and sustaining fish and wildlife resources.