Date of Award

5-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Wildlife and Fisheries Biology

Advisor

Yarrow, Greg K

Committee Member

Gerard , Patrick D

Committee Member

Jodice , Patrick G

Abstract

Species reintroduction projects are becoming more common as a conservation tool to reestablish populations following extirpation. The implementation of these projects can be controversial due to the potential impact the reintroduced animal could have on endangered, threatened, or at risk prey species. In 1999, South Carolina's Department of Natural Resources (SCDNR) reintroduced the American mink (Neovison vison), a SCDNR designated species of high conservation priority, to the northern coastal marshes of the state, including Cape Romain National Wildlife Refuge (CRNWR). In order to estimate the impact of this opportunistic predator on other species, especially those of special concern to the US Fish and Wildlife Service (USFWS) at CRNWR, a literature-based bioenergetics model was constructed using diet analysis data from 45 mink stomach/gastrointestinal tracts collected from CRNWR. Diet was predominately crustacean (51.9% of prey occurrences) and fish (40.7%) with occasional avian occurrence (7.4%). The bioenergetics model estimated, on average, that a single mink could consume 158 crustacean, 38 fish, and 8.5 avian prey items per month.
Additionally, 7 female mink were captured, implanted with an intraperitoneal transmitter, and monitored from March through August (2010 and 2011) to determine home range size and activity pattern. Average lactating female mink home range and core area measured 2.12 ha and 0.26 ha, respectively, and average linear home range (i.e., marsh edge utilization within home range) measured 1.0 km. Lactating female mink activity was negatively related to tide height. Although activity was not significantly influenced by temperature and light, lactating female mink appeared to be less active during the day, especially at mid-day when temperatures were high. Based on the findings of this study and others that have monitored avian species of concern in CRNWR, predation (e.g., mink, raccoon, great horned owl, black vulture, rat, and ghost crab) has been demonstrated to contribute to lost shorebird and seabird productivity (i.e., nest loss or chick loss). Since mink, American oystercatcher, least tern, and black skimmer have high conservation value in South Carolina, further monitoring and research of the interaction of these species is necessary to restore the historical ecological integrity of the system. A joint mink culling-relocation program between SCDNR and USFWS at CRNWR could benefit both mink and beach-nesting bird conservation.

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