Mammal Occurrence in Rock Outcrops in Shenandoah National Park: Ecological and Anthropogenic Factors Influencing Trap Success and Co-Occurrence
2017
Lombardi, Jason V. | Mengak, Michael T. | Castleberry, Steven B. | Terrell, Vanessa K.
Montane rock outcrops are a sensitive habitat type throughout the Appalachian Mountains. These areas provide habitat for a variety of endemic or rare fauna and flora species assemblages. Our objective was to conduct a status survey of focal mammal species considered rare in the Appalachian region, including Allegheny woodrat (Neotoma magister), eastern spotted skunk (Spilogale putorius), least weasel (Mustela nivalis), long-tailed weasel (Mustela frenata), and fisher (Martes pennanti) at rock outcrops in Shenandoah National Park, Virginia. From 7 May to 27 September 2015, we conducted camera surveys at 48 rock outcrop sites in the Park. Over 1,985 trap nights (TN), we obtained 2,572 images and detected 16 mammalian species. We quantified capture success, related success to a set of predefined landscape variables and determined co-occurrence patterns of various species. Allegheny woodrats had the highest capture success (10.7%; 212/1,985 TN); however, black bears (Ursus americanus) and raccoons (Procyon lotor) were both detected at greater than 90% of sites. Allegheny woodrats were captured more frequently at outcrops that were farther from rights-of-way, roads, and development. The best predictor of capture success for eastern spotted skunks was distance from rights-of-way. We report the greatest capture success of long-tailed weasels using game cameras as compared to previous studies. Domestic dogs (Canis lupus familiaris) had a negative impact on co-occurrence of all species at sites where they were detected. The presence of several uncommon species in this habitat type, in addition to negative effects of dogs, warrants the need for continued monitoring and habitat protection.
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