ECOSYSTEM CHANGE AT MULTIPLE TEMPORAL AND SPATIAL SCALES: LINKING HYDROLOGY, GEOMORPHOLOGY AND ECOLOGY ON THE ROANOKE RIVER FLOODPLAIN, NORTH CAROLINA

The Roanoke River in eastern North Carolina is reputed to have the largest and least disturbed expanse of bottomland hardwood forests on the Eastern Seaboard. Despite this, the river and its floodplain have experienced a wide range of anthropogenic impacts since European settlement, including altered hydrology due to dams, increased sedimentation due upland forest clearance, and numerous other modifications resulting from human activities at a variety of spatial and temporal scales (e.g., logging, levee construction and breaches, road-building, etc.). Management and restoration of this seemingly pristine ecosystem are thus challenged by the difficulties in distinguishing between the impacts of recent (<50 yrs) and historic (<300 yrs) human activities, and then distinguishing human mediated processes from otherwise natural dynamics. We have used methods of modeling, statistics, paleoecology and remote sensing derived from such disciplines as geology, geography, geomorphology, plant ecology and landscape ecology to provide insight into the processes affecting current floodplain patterns and to help establish management priorities. Our research results indicate excessive post-settlement sediment deposition (> 5 m in places, more than the total deposition of the previous 10,000 years). Moreover, the hydrologic regime has been altered dramatically in recent decades, extending spring floods into the growing season and potentially altering forest growth rates and successional dynamics. These data and the results of our research are being used by non-government organizations, state and federal agencies, and public corporations dependent on the river to help guide future river management to sustain both the ecosystem and the economies dependent on the river system.