Date of Award

Spring 5-14-2020

Document Type

Thesis

Degree Name

Master of Biological Science (MBioSci)

Department

Biology

First Advisor

Dr. Alfred Mead

Second Advisor

Dr. Katie Stumpf

Third Advisor

Dr. Matthew Milnes

Abstract

Density estimation is an important indicator of the health of wildlife populations and is commonly used to establish management practices. Trail-cameras offer a unique advantage in the density estimation of elusive animals as data can be collected without the need for physical capture. The objectives of this study were to estimate and compare furbearer density between two major habitats at the Piedmont National Wildlife Refuge (PNWR) and to compare computed density values from paired cameras located at off- and on-road locations. An additional goal was to assess the usefulness of trail-cameras as a viable technique to estimate population density on the refuge. Trail-camera monitoring took place from April to September of 2019. Density estimates for five furbearer species were calculated using a model developed for animals not uniquely identifiable. Virginia opossums were the most frequently observed furbearer, followed by coyotes, raccoons, bobcats, and gray foxes. Average density estimates between bottomland and upland habitats did not differ significantly among all observed species. Values obtained at off- and on-road locations in upland habitat was significantly different only for the coyote (p=0.02). Density estimates in bottomland were not significantly different than on-road locations in upland areas for opossum, raccoon, and gray fox (p= 0.89, 0.13, 0.15), however, coyote and bobcat estimates were significantly higher at on-road locations (p=0.001, 0.04). A comparison of habitat and elevation was largely insignificant across species, except for raccoons (p=0.04). Data collected for this species suggested lower elevation areas had higher density levels. Camera deployment and monitoring was laborious and time consuming. Wildlife officials aiming to collect population data on opossums and gray foxes should consider placing cameras directly on roads as it is less labor intensive and provides similar density estimates between habitats. For raccoons, elevation may be a better indicator of density, with higher values observed at lower elevations. Cameras monitoring raccoons should be placed on roads with different elevations. Cameras used to monitor bobcats and coyotes should be located off-road to ensure a more representative sample. For general species monitoring, on-road camera placement would be sufficient as all observed species were seen at least once at these locations.

Comments

Density estimation is an important indicator of the health of wildlife populations and is commonly used to establish management practices. Trail-cameras offer a unique advantage in the density estimation of elusive animals as data can be collected without the need for physical capture. The objectives of this study were to estimate and compare furbearer density between two major habitats at the Piedmont National Wildlife Refuge (PNWR) and to compare computed density values from paired cameras located at off- and on-road locations. An additional goal was to assess the usefulness of trail-cameras as a viable technique to estimate population density on the refuge. Trail-camera monitoring took place from April to September of 2019. Density estimates for five furbearer species were calculated using a model developed for animals not uniquely identifiable. Virginia opossums were the most frequently observed furbearer, followed by coyotes, raccoons, bobcats, and gray foxes. Average density estimates between bottomland and upland habitats did not differ significantly among all observed species. Values obtained at off- and on-road locations in upland habitat was significantly different only for the coyote (p=0.02). Density estimates in bottomland were not significantly different than on-road locations in upland areas for opossum, raccoon, and gray fox (p= 0.89, 0.13, 0.15), however, coyote and bobcat estimates were significantly higher at on-road locations (p=0.001, 0.04). A comparison of habitat and elevation was largely insignificant across species, except for raccoons (p=0.04). Data collected for this species suggested lower elevation areas had higher density levels. Camera deployment and monitoring was laborious and time consuming. Wildlife officials aiming to collect population data on opossums and gray foxes should consider placing cameras directly on roads as it is less labor intensive and provides similar density estimates between habitats. For raccoons, elevation may be a better indicator of density, with higher values observed at lower elevations. Cameras monitoring raccoons should be placed on roads with different elevations. Cameras used to monitor bobcats and coyotes should be located off-road to ensure a more representative sample. For general species monitoring, on-road camera placement would be sufficient as all observed species were seen at least once at these locations.

Available for download on Friday, May 14, 2021

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