Deer-mediated changes in environment compound the direct impacts of herbivory on understory plant communities

1. In forests of eastern North America, white-tailed deer (Odocoileus virginianus) can directly affect, via herbivory, the presence, abundance, and reproductive success of many plant species. In addition, deer indirectly influence understory communities by altering environmental conditions.
2. To examine how deer indirectly influence understory plants via environmental modification, we sampled vegetation and environmental variables in- and outside deer exclosures (10-20 years old) located in temperate forests in northern Wisconsin and the Upper Peninsula of Michigan, USA. We assessed how excluding deer affected understory community composition and structure, the soil and light environment, and relationships between direct and indirect effects using non-metric multidimensional scaling (NMDS), mixed linear models and non-parametric multiplicative regression (NPMR).
3. Excluding deer altered sapling communities and several aspects of the understory environment. Excluding deer from plo...