Semester

Fall

Date of Graduation

2008

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Wildlife and Fisheries Resources

Committee Chair

John W. Edwards.

Abstract

White-tailed deer (Odocoileus virginianus) are the most abundant big game species in North America and serve as the dominant herbivore in the majority of the Appalachian region. Despite the abundance of research conducted on this species, relatively little is known of the ecology of white-tailed deer occurring at low densities. Our study population experienced a 75% decline in population density and a three-fold increase in habitat disturbance via timber harvests between 2002 and 2005. From May 2006 to April 2008 I examined the home-range, survival, and herbivory patterns of a central Appalachian white-tailed deer herd that has recently experienced both a substantial decline in population density and now occurs at extremely low densities (1--3/km 2). Home-range and core-area size did not differ among age classes in any season. Annual home-range size of yearlings (505 ha) was larger than for adults (313 ha), although core-area size did not differ. Within age classes there were no seasonal differences in home-range or core-area size. Home-range site-fidelity did not differ among age classes for any season or among seasons for any age class. Core-area site fidelity was higher in fall (74%) than in summer (45%) or winter (36%) when pooled across age classes but did not differ among age classes. Survival was lower during the fall (0.89) than during summer (0.99) or winter (0.94). Human-induced mortalities (n = 12) constituted 67% of all observed mortalities during the study; all mortalities were in the adult age class. Woody browse abundance differed among plot types, with clearcut interior (50.16 twigs/plot) plots having more browse than clearcut edge (31.95 twigs/plot) or mature forest (18.93 twigs/plot) plots. Browsing rates of woody plants was higher in clearcut edge plots (5.55%) than in clearcut interior (3.99%) or mature forest plots (3.32%). Observed home-range and core-area sizes were substantially larger than previously reported for the same population prior to declines in density. This supports previous work that suggests home-range size is inversely related to population density and positively correlated with habitat disturbance. Survival rates were similar to previously reported, suggesting that adult survival is robust to changes in population density. Previously reported browsing rates were approximately 5 times the levels reported herein, however such a decrease would be expected with reduced population density and an increase in browse abundance, both of which occurred on the study site.

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