Plant communities associated with different shoreline elements at Cave Run Lake, Kentucky

Abstract

The purpose of this research was to determine if slope and exposure are important determinants of plant communities emerging on reservoir shorelines. We sampled 30 sites on the previously inundated shoreline of Cave Run Lake, a U.S. Army Corps of Engineers flood-control reservoir in east-central Kentucky, USA. These sites were categorized as either flats, riparian forests, exposed banks, or sheltered banks Two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis were used with presence/absence data to group sites of similar community composition. These were 167 species of plants identified in the study plots, of which 29% were annuals, 2% were biennials, 69% were perennials, 11% were non-indigenous, and 63% met the criterion for inclusion in community analysis. A distinct assemblage of plant species was associated with all riparian forests, with six of eight flats, and with five of twelve exposed banks. Six sheltered banks were not obviously associated with a single community type. The TWINSPAN group including riparian forests had the highest percentage of wetland species; the TWINSPAN group including most flats had the highest species richness; the TWINSPAN group comprised entirely of exposed banks had low species richness and low representation of wetland species. Our results suggest that plant communities of high conservation value can emerge on relatively flat sites under a human-controlled flooding regimen as long as the soil remains intact. However, steep exposed banks are susceptible to soil loss, and the resulting rock substrates support a depauperate flora of low conservation value.