Semester

Fall

Date of Graduation

2014

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Forest Resource Management

Committee Chair

James T. Anderson

Committee Co-Chair

James Crum

Committee Member

John Edwards

Committee Member

James Rentch

Committee Member

Robert Whyte

Abstract

White-tailed deer (Odocoileus virginianus) may impact plant species by reducing individual survival or reduce reproductive potential by feeding on flowering parts or seeds. Herbivory may benefit plant populations by increasing dispersal of seeds. The combination of these factors may influence the composition of native plant communities. The recovery of deer populations from near extirpation was seen as a wildlife management success story. However, the maintenance of abnormally high deer density levels over many years may have taken a toll on plant communities. Some biologists now question whether or not white-tailed deer could be considered overabundant in some parts of their range. An overabundant population of white-tailed deer may affect ecosystem function by changing the abundance and distribution of preferred browse plants. Much of the research concerning the effects of deer on plant communities has focused on their role as browsers and the potential for overbrowsing of upland plant species. Fewer studies of deer diet have been directed solely toward rare or endangered herbaceous or woody plants. Populations of rare species often have a metapopulation distribution. That is, they exist in a series of local populations, due either to natural distribution or to the effects of human disturbance that are linked by dispersal. Many rare or declining species exist in non-equilibrium metapopulations in which the rate of colonization is not sufficient to counter rates of local extinction. Dispersal of plants is tied directly to reproduction and some plant species may rely on herbivores as seed dispersers to aid seed dispersal into new patches. The purpose of this study is to evaluate the influences of white-tailed deer browse on plant populations in West Virginia. The study was organized into three general sections: 1) the influence of white-tailed deer browse and seed dispersal on rare plant species and communities in Canaan Valley, West Virginia, 2) the impact of white-tailed deer density on forest understory recruitment in upland forests throughout West Virginia, and 3) public attitudes toward rare plant conservation and white-tailed deer management.;My study suggests that white-tailed deer may consume almost 100% of the sexually reproductive ramets within some P. vanbruntiae populations in a given year. As P. vanbruntiae can reproduce clonally, high levels of seed loss such as those exhibited here may not immediately affect population persistence. However, a reduction in dispersal may reduce genetic diversity and the formation of new populations. At the community level, elevated deer densities present in the post-logging era impact the herbaceous community by selectively browsing forb species, especially in the spring. On a state-wide scale, the density of white-tailed deer impacting the control plots at many of these sites has been at or exceeded the capacity of the upland forest to regenerate the current community. At some sites, few, overstory species are currently reaching the understory growth level thus the future of the forest cover at these sites is uncertain. However, the potential still exists to regenerate the current forest community at many sites. However, if browse pressure persists as the seed sources decline, the potential for recovery of the current ecosystem will likewise decline. A difference in proportion of stems from upland species that germinated from fecal samples in 2006 suggests that upland plants may be more adapted to dispersal by white-tailed deer, though this difference in frequency might be attributed to the success of a few FACU plants. Dispersal of graminoid species by deer may help to maintain or expand herbaceous openings at both wetland and upland sites by dispersing the seeds of graminoid species as well as reducing the capacity for woody species regeneration. Although many of the views of residents and nonresidents were similar, Tucker County residents were less likely to favor rare plant conservation. Many of the visitors and nonresidents come to Canaan Valley specifically because of its unique characteristics and appear to place more value on these unique plants. Recognition of differences in attitudes between stakeholder groups could be helpful in designing educational programs for users of natural areas. In this case, education and emphasis on the importance of rare plant diversity in Canaan Valley may bring more local support for their conservation. (Abstract shortened by UMI.).

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