Ungulate-Disturbance Interactions in Hemlock Ecosystems at Harvard Forest since 2012

Densities of ungulates are often associated with recent forest disturbances (such as fire, logging and insect outbreaks) as increased resources stimulate tree regeneration, leading to abundant available browse. Despite the often significant role that ungulates play in disturbed forests, surprisingly little is known about ungulate-disturbance interactions. Ungulate herbivory is often excluded from examinations of forest response to disturbance. In the Northeastern United States, a large-scale insect outbreak, the hemlock wooly adelgid (HWA), has begun to have important effects on hemlock forests, both directly and indirectly (i.e., by preemptive salvage logging). No studies have examined the interactions of both moose and deer activity with these associated canopy disturbances. The authors examined the relative abundance of moose and deer in four treatments (2 replicates) at the Hemlock Removal Experiment using three indices of ungulate activity: pellet group density, evidence of past browsing on seedlings and saplings, and the occurrence of animals using game cameras. They also monitored the response of vegetation to ungulate browsing by sampling woody and herbaceous vegetation in fenced enclosures and paired controls in disturbed and undisturbed plots.