Date of Award

5-18-2014

Document Type

Honors Thesis

Department

Environmental Science

First Advisor

Carol Loeffler

Language

English

Abstract

Overabundance of white-tailed deer (Odocoileus virginianus Zimmerman) is a growing problem throughout the eastern United States. This study investigates the role that deer play as seed dispersers focusing on two main questions. Are they now spreading invasive plant species? Which species are viable after passing through the deer? I compare seed dispersal by white-tailed deer at two contrasting sites: the Florence J. Reineman Wildlife Sanctuary in Landisburg, Pennsylvania, where heavy deer browsing has eliminated the understory allowing invasive species such as Asian stilt grass (Microstegium vimineum (Trin) A. Camus) to take over the forest floor, and a nearby stretch of heavily-hunted forest (State Gamelands170) with comparable canopy tree composition but with a dense understory. Twenty- four deer pellet samples containing between 10 and 30 pellets were collected from the two locations, 13 from Reineman and 11 from the state gamelands. Half of each sample was planted to investigate germination rates, and the other half was dried and sorted for seed counts and types. Thirty-three species of seeds were extracted and fourteen were identified. An additional nine species were identified from the germinated plants. In total, thirty-six plants germinated. The species distribution was significantly different between the two sites and had very little overlap in dominant species. The species found in the Reineman Wildlife Sanctuary samples tended to be field herbs which require full sun suggesting that the deer are foraging in fields in or near the sanctuary. The state gamelands samples contained more shade tolerant woods plants. Despite these differences between the sites, the seed and plant data suggest that the deer at both RWS and SGL disperse invasive and native species comparably. About 30 percent of the seeds in the pellet piles at both locations were nonnative. This is important for the future management of the Reineman Wildlife Sanctuary and similar sanctuaries throughout Pennsylvania and the east coast.

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