Population Ecology of Black Bears in the Alleghany Mountains of Virginia
dc.contributor.author | Bridges, Andrew Scott | en |
dc.contributor.committeechair | Vaughan, Michael R. | en |
dc.contributor.committeemember | Steffen, David E. | en |
dc.contributor.committeemember | Walters, Jeffrey R. | en |
dc.contributor.committeemember | Stauffer, Dean F. | en |
dc.contributor.department | Fisheries and Wildlife Sciences | en |
dc.date.accessioned | 2014-03-14T20:12:09Z | en |
dc.date.adate | 2005-05-26 | en |
dc.date.available | 2014-03-14T20:12:09Z | en |
dc.date.issued | 2005-04-29 | en |
dc.date.rdate | 2008-05-26 | en |
dc.date.sdate | 2005-05-17 | en |
dc.description.abstract | The Cooperative Alleghany Bear Study (CABS) was a 10-year study conducted on 2 areas and designed to investigate the ecology of a hunted population of American black bears (Ursus americanus) in the Alleghany Mountains of western Virginia. Over the course of our research, we handled 1,041 individual bears >18 months old and gathered reproductive data from females during 424 bear-winters. My analyses of 183 litters indicate that reproductive rates were high with relatively large litters (mean = 2.49 cubs / litter) and younger (3–4-year-old) females having smaller litters than older (> 5 years old) females. Overall cub sex ratios did not differ from 1M:1F; however, female cubs were over-represented in 4-cub litters. Most cubs were born in January (mean = January 17) and younger females had later parturition dates than older females. Bears on our study areas had relatively early ages at primiparity (mean = 3.8 years old) and few missed reproductive opportunities. Hard mast failure apparently resulted in periodic reproductive failures and subsequent reproductive synchrony, which I tracked using 5 indices. The amplitude of oscillations in reproductive synchrony dampened through time after each synchronizing event. The population contained substantially more females than males; however, males were more vulnerable to trapping than were females. Population size was determined using genetic and photographic capture-recapture estimators. Density estimates were relatively high and approached 1 bear / km2. Annual survival rates were high for cubs (0.87) and females (0.91). For males, annual survival rates were lower, particularly for 1–3-year-olds (0.57). Excluding hunting mortality, natural survival rates were high (0.98) for all >1-year-old bears on our study areas. The results of Leslie Matrix and Program RISKMAN models indicated a growing population. A Leslie Matrix model incorporating the effects of a 5-year-cyle of mast-failure-induced reproductive failure yielded a lambda = 1.13. To reach the objective of 0 population growth prescribed for some areas of Virginia, increased levels of hunting mortality on adult (>3-year-old) females would likely be necessary. | en |
dc.description.degree | Ph. D. | en |
dc.identifier.other | etd-05172005-181300 | en |
dc.identifier.sourceurl | http://scholar.lib.vt.edu/theses/available/etd-05172005-181300/ | en |
dc.identifier.uri | http://hdl.handle.net/10919/27754 | en |
dc.publisher | Virginia Tech | en |
dc.relation.haspart | Bridges_ETD.pdf | en |
dc.rights | In Copyright | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
dc.subject | survival | en |
dc.subject | American black bear | en |
dc.subject | demographics | en |
dc.subject | population dynamics | en |
dc.subject | Reproduction | en |
dc.subject | Ursus americanus | en |
dc.title | Population Ecology of Black Bears in the Alleghany Mountains of Virginia | en |
dc.type | Dissertation | en |
thesis.degree.discipline | Fisheries and Wildlife Sciences | en |
thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
thesis.degree.level | doctoral | en |
thesis.degree.name | Ph. D. | en |
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