Response of litter-dwelling ants to experimental removals of white-tailed deer and Amur honeysuckle in eastern deciduous forest

The overabundance of white-tailed deer (Odocoileus virginianus) and the presence of an invasive shrub, Amur Honeysuckle (Lonicera maackii) have strong effects on ecosystem processes in the eastern deciduous forest of North America. Both deer and Amur honeysuckle decrease abundance and richness of seedlings, saplings, and herbaceous plants in the forest understory, but few studies have examined how they alter litter-dwelling arthropods. Ants (Formicidae), in particular, play key functional roles in forest ecosystems, acting as ecosystem engineers, predators, and seed dispersers. Potential changes to ant abundance and community structure can have cascading effects on various ecosystem processes. We examined the response of the ant community to long-term deer exclosure and honeysuckle removal in a mid-successional deciduous forest of southwestern Ohio. Ant species richness, composition, and abundance as well as leaf litter biomass were sampled and analyzed from five sites from 2011 to 2015. The sites consisted of a 20x20-m deer exclosure paired with a control plot, each with a split-plot removal of honeysuckle. Ant richness and abundance were positively related to standing leaf litter biomass, but community composition was not significantly different among treatments. Additionally, we found a negative effect of deer presence on leaf litter biomass, but a slight positive effect of honeysuckle presence on leaf litter biomass. While our results show little effect of Amur honeysuckle on the leaf litter ant community, these results provide evidence that deer overabundance has local negative impacts on the biodiversity of these communities, which may have cascading effects on forest ecosystem functioning.