Ungulate-Disturbance Interactions in Hemlock Ecosystems at Harvard Forest 2012-2013

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, and 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. Our objectives are twofold: to determine (1) the response of ungulates to varying disturbance types and intensities and (2) the influence of ungulate interactions with canopy disturbance on vegetation, other biota, and ecosystem processes. We will examine 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. We will also monitor the response of vegetation to ungulate browsing by sampling woody and herbaceous vegetation in fenced exclosures and paired controls in disturbed and undisturbed plots.