Collaborative Research: Modeling the Impacts of Post-Settlement Sediment Deposition on Floodplain Vegetation

University Of North Carolina At Chapel Hill, Chapel Hill NC

Investigators

Abstract

0128321 Peet Temperate river systems and their associated floodplains have been substantially altered by human activity. Although the effects of dams on river hydrology and downstream ecosystems have been studied extensively, data on how changes in historic sedimentation regimes and geomorphology affect floodplain ecosystems is practically nonexistent. This research will demonstrate for an entire model river system (the Roanoke River of North Carolina) the degree of post-colonial landscape-scale ecosystem alteration due to sediment deposition, and the future changes likely to affect vegetation dynamics as those sediments are redistributed and transported out of the system. We will test a series of specific hypotheses centered on the following: (1) Anthropogenic sediment deposition on the Roanoke River floodplain over the last 250 years has led to a dramatic alteration of the extent and distribution of landforms within the geomorphologic system; (2) The vegetation of the lower Roanoke floodplain has been substantially altered as a consequence of environmental changes due to geomorphic alterations from post-colonial sedimentation; (3) Models of sediment-impacted riparian areas developed from geomorphologic and paleoecological data can be used to predict future landforms and vegetation composition. To address these hypotheses we will integrate dendrogeomorphic, palynological and modeling techniques to (1) develop a spatially explicit model of post-colonial sediment accumulation for the lower Roanoke River floodplain, (2) model the pre-colonial geomorphic landscape and simulate future floodplain geomorphology, and (3) predict vegetation distributions for those surfaces using vegetation-environment relationships.