Document Type

Thesis - Open Access

Award Date

2017

Degree Name

Master of Science (MS)

Department

Natural Resource Management

First Advisor

Jonathan A. Jenks

Keywords

grassland, reintroduction, South Dakota, swift fox, Vulpes velox

Abstract

Swift foxes (Vulpes velox) were reintroduced into Badlands National Park between 2003 and 2006 after being nearly extirpated from South Dakota in the early 1900’s. Genetic analysis provided strong evidence that the reintroduction was successful, but viability analysis indicated the population may be in jeopardy with a high probability of extinction. Recently, the population has declined due to various biotic and abiotic factors (e.g., recent weather patterns, effects of plague [Yersinia pestis], and increased coyote [Canis latrans] numbers). No information on the status of swift foxes has been collected since 2009. Between 2014 and 2016, the objectives of this study were to 1) document the current distribution of swift foxes in southwestern South Dakota; 2) estimate survival and cause-specific mortality; 3) document active dens to estimate reproductive success; and 4) assess the presence of swift foxes in areas affected by plague. Over 1,000 scent stations were deployed across a seven county area in southwest South Dakota; only 1.7% of the stations detected swift foxes, and in only two counties. Foxes were not detected in two of the counties that had presence within the last ten years. Forty-six swift foxes were trapped, radio-collared, and tracked around Badlands National Park, and 12 natal dens were monitored. Yearly reproductive success was estimated using motion activated trail cameras, and averaged 4.3 ± 0.3 pups per mated pair. Natal dens had more holes (4.4 ± 0.7) than non-natal dens (2.2 ± 0.4) and were closer to roads (160.9 ± 57.0 m) and closer to anthropogenic features (105.8 ± 36.5 m) than random locations (roads: 557.4 ± 155.1 m; anthropogenic 341.2 ± 67.2 m). An additional objective 5) was added when pups from two orphaned dens were hand reared in an accredited zoo and subsequently returned to their natal dens; none of the foxes survived to become adults after release. Survival was estimated using the Kaplan-Meier procedure for staggered entry; apparent annual survival for collared adults was 0.51 (95% CI = 0.24–0.69; n = 14), and for collared pups was 0.19 (n = 8). Cause-specific mortality of collared foxes was attributed to vehicle collision (n = 7; 33.3%), coyote (n = 7; 33.3%), raptor (n = 3; 14.3%), and unknown origin (n = 4; 19.1%). Antibodies to Y. pestis were found in 69.9% of sampled foxes using enzyme-linked immunosorbent assay (ELISA) analysis. Data from this study raises concern for the status of the population. An apparent decline in distribution, a decline in numbers around Badlands National Park, a decreased survival rate in pups, and the presence of plague may lead this population to extinction in the near future. Another reintroduction is not recommended until biotic and abiotic factors correlated to the decline are mitigated and swift fox presence is determined in other regions of South Dakota.

Library of Congress Subject Headings

Kit fox -- Reintroduction -- South Dakota -- Evaluation.
Kit fox -- Reintroduction -- South Dakota -- Badlands National Park -- Evaluation.

Description

Includes bibliographical references (pages 117-119)

Format

application/pdf

Number of Pages

130

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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