Poster: Influence of channel morphology on stream bank vegetation
 
Joseph Smith

 
In this study, we investigated the relationship between stream channel morphology and the distribution of wetland and upland species in the riparian zone of the Gwynns Falls, in order to test the hypothesis that vegetation shifts from wetland species to species that prefer drier habitats as stream morphology changes from shallower banks to steeper banks where flooding is less frequent.
 
We sampled 45 transects consisting of 111 10x10 meter plots in the Gwynns Falls and its tributaries. At each sampling location, the stream channel, the width of the riparian zone perpendicular to the stream channel, and the elevation across the entire transect relative to the stream bottom, were measured, and the ratio of the height of stream-bank to channel width was calculated. All vegetation was sampled in each 10x10-meter plot starting at the bank edge and every 30 meters beyond to the end of the riparian zone. The wetland indicator index (US Fish and Wildlife 1996 National Wetland Inventory Survey) was used to describe the habitat preference for each species. The index assigns a numeric value to each preference ranging from 1 to 5 where 1 is assigned to species restricted to wetland areas and 5 to species limited to upland areas. Each plot was assigned a wetness number, ranging from 1 to 5, based on the composition and abundance of the vegetation sampled. Comparisons were then made between plots to correlate vegetation and channel morphology.