Spiders as a gauge for change: linking spider density to riparian habitat structure

Lily Tanner, a student at New College of Florida, worked with Denzell Cross and Dr. Krista Capps.

Abstract: Urbanization often compromises the diversity and abundance of native species living in watersheds (Rodrigues et al., 2015). Research has shown that riparian spiders are susceptible to land use change associated with urbanization (Sanchez-Ruiz et al., 2017).  We conducted  a spider density survey in riparian habitats in and around Atlanta as a metric to assess the impact of urbanization on regional spider populations. We hypothesized that if overhanging vegetation was important web-building substrate for some taxa  and vegetation provided cover for ground-dwelling species, then the highest density of spiders would be found in transects with vegetation hanging over the stream. Our results indicate that overhanging vegetation was related to higher densities of web-weaving species. Increasing amounts of overhanging vegetation was also related to increasing bank slope, suggesting there may be potentially important interactions between physical and biological characteristics of riparian areas that mediate spider population structure.