Exclusion of Overabundant White-tailed Deer (Odocoileus virginianus) Results in Shifts in Soil Microbial Communities and Abiotic Soil Condition in a Northeastern Deciduous Forest

Past and current anthropogenic practices have resulted in dramatic alterations to ungulate population densities worldwide. When ungulate populations are overabundant, they can alter the dynamics, structure, and function of ecosystems. White-tailed deer (Odocoileus virginianus), specifically, can occur at densities far greater than their historical records in parts of their native range, which includes forests in the northeastern U.S. They have been shown to alter community structure of native plants, indirectly impact animal communities, and promote the success of invasive species. Despite much research into the effects of overabundant ungulates and deer in particular, less is known about the effects of deer on soil microbial communities. Here, we utilized soil samples from inside and outside of six deer exclosures located in a regional second growth mixed hardwood forest on the Binghamton University campus in Vestal NY, U.S.A. A metagenomic analysis was conducted on DNA extracted from the soil to identify the microbes present. Soil characteristics, including soil organic matter, soil moisture, pH, and electrical conductivity were also measured. Soil samples from inside exclosures had on average lower pH, higher soil moisture and organic matter, and higher electrical conductivity. The microbial communities across all samples were dominated by Proteobacteria, Acidobacteria, and Actinobacteria. However, the structure of the microbial soil community appeared to differ between samples taken inside and outside the exclosures, with those taken outside more closely resembling other outside samples and those sampled inside soils showing more variability in community structure. Overall, our results suggest that overabundant deer may have a homogenization effect on the soil abiotic environment and the soil microbial community.