PS 46-180 - No impact of white-tailed deer and invasive plant management on spider diversity and composition in a post-agricultural woodland

Wednesday, August 9, 2017
Exhibit Hall, Oregon Convention Center
Christopher W. Habeck, Lauren Fierman and Margot Shrift, Department of Biology, Kutztown University, Kutztown, PA

The biophysical structure of understory plant communities plays a crucial role in the abundance and identities of higher trophic levels, including spiders. Web building spiders require dimensional complexity in their environment to build effective webs, and all spiders rely on the vegetative structure in their environment for sensory purposes. In many northeastern temperate forests, invasive plants and white tailed deer (Odocoileus virginianus) overabundance pose threats to this important component of spider habitat in the forest understory. Here, we report preliminary analyses of an experiment that explores the impact of forest restoration techniques (namely, white-tailed deer exclusion and invasive plant removal) on the composition, diversity and abundance of plant-dwelling spiders in a post-agricultural woodland. The experiment, which was initiated in 2013, consisted of sixteen 100m2 plots, with four plots per treatment combination of deer removal or control and invasive plant removal or control. We sampled spiders in the plots during Fall 2016 with a sweep net, stored them in alchohol at 20°C until processing, and identified them to the morpho-species level. We used univariate and multivariate statistical techniques to evaluate the effects of our restoration management on spider composition, diversity and abundance.


We identified 54 morpho-species of plant-dwelling spiders across all plots. The average richness of spiders per plot was 7.8 ±1.7 SE. Richness did not differ among treatments (F2,9= 0.322, P=<0.05). Similarly, Shannon diversity did not differ by treatment (F2,9= 0.872, P=<0.05) and averaged 1.6 ±0.2 SE per plot. Finally, the species composition as assessed by permanova analysis did not differ among treatments (pseudoF2,9= 0.929, P=<0.05). Overall, we found no positive or negative impacts of invasive plant removal or deer exclusion on the spider community. We are in the process of exploring the potential influence of web-attachment opportunities within plots as a possible covariate to explain residual variance within the data. Currently, however, we feel that forest restoration efforts in our research area are having no unintended detrimental effects on the spider community.