Effects of Riparian Vegetation and Local Habitat Quality on the Diversity and Abundance of Fish In Piedmont Streams of South Carolina

Prior research on rural Piedmont streams in South Carolina suggests that watershed level land cover does not explain differences in fish diversity or abundance among different streams. However, observations at these sites suggest significant differences in the riparian zone over small spatial scales along the same stream. Due to the high mobility of fish, it is possible that they can choose more favorable stream reach habitats at this smaller spatial scale, explaining why fish abundance and diversity are poorly correlated with watershed level land cover. Therefore, the focus of our research has been to study the ways in which local riparian vegetation and local habitat quality impact fish populations in streams. We predict that higher density of riparian vegetation along the stream will correlate with a greater abundance and diversity of local fish populations. To test this hypothesis, we sampled each stream at two adjacent stream reaches with different riparian cover. Within each stream reach we measured channel geomorphology and instream canopy cover, collected fish and sediment, and characterized the riparian zone next to the stream by measuring percent ground cover, canopy cover, and the number of trees and shrubs above 4.5 feet at six random points. Our results show that Simpson’s diversity is negatively correlated with percent ground cover and percent forest in the watershed. We also found that Simpson’s diversity is positively correlated with percent grass and pasture in the watershed, average mean sediment size in phi, and entrenchment ratio