Estimation of Predator Densities in Western South Dakota

Evaluation of methods for predator density estimation is necessary to assess biases in techniques and determine those best suited to local conditions. Knowledge of predator populations allow wildlife managers to prescribe and assess management and control activities. Objectives of this study were to assess the use of relative density estimation techniques for coyote (Canis latrans), red fox (Vulpes vulpes), and striped skunk (Mephitis mephitis) populations in western South Dakota, to determine if temporal variation of these populations occurred within study areas, and to determine absolute densities of the above species. Relative densities of coyote, red fox, and striped skunk populations were determined using scent-station (SS) surveys, fecal line (FL) surveys, road-kill surveys (RK), and catch-per-unit-effort (CPUE) techniques. Absolute densities of coyote, red fox, and striped skunk populations were determined using the minimum density estimate technique. Techniques were evaluated on a monthly basis in Harding County (Northwest study area) and Haakon and Jackson counties (Westcentral study area), South Dakota from February through July 1995 and from February through October 1996. Ease of use, cost, and the ability of the techniques to be used over a wide geographic area were factors of importance when evaluating methods of density estimation. Field necropsies were performed on trapped animals that were removed from the population. Of these trapped animals, canine teeth were extracted for aging, blood sampled, and nutritional condition was evaluated. In addition, small intestines were removed and parasite loads were determined. Spearman rank correlations were conducted to determine which techniques possessed similar trends in indices. Road-kill surveys were eliminated from consideration as a relative density estimation technique because of low Spearman Rank Correlation coefficients. Non-continuous sampling, high costs, and difficulty in standardization eliminated CPUE from consideration as a relative density estimation technique. When data from all sampling periods were included in analyses, no differences (P ≥ 0.018) in population abundance were observed within and across study areas using SS surveys; differences (P ≤ 0.014) in predator populations within and across study areas were observed using FL surveys. Absolute density estimates for 1995 were 0.61 striped skunks/km2 in the northwest study area. Absolute density estimates for 1996 were 2.28 red foxes/km2 and 1.3 striped skunks/km2 in the northwest study area and 0.22 coyotes/km2 and 1.89 striped skunks/km2 in the westcentral study area. No temporal variation (P ≥ 0.20) of coyote, red fox, and striped skunk populations was observed within study areas. All trapped animals were determined to be in good nutritional condition and all were negative for presence of Echinococcus multilocularis, a parasite associated with alveolar hydatid disease in humans. Fecal line surveys were more powerful in detecting differences in population abundance of predators due to fewer environmental and behavioral biases associated with this method. It is recommended that the South Dakota Department of Game, Fish, and Parks conduct FL surveys during March and September to monitor predator populations in western South Dakota.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis - University Access Only

Discipline thesis:degree_discipline

Wildlife and Fisheries Science

Year

1997

Author dc:creator

• Kost, Craig D.

Contributors dc:contributor

• Jonathan A. Jenks

• Natural Resources and Conservation

Statement dc:rights

• Copyright © 1997 Craig D. Kost. All rights reserved.

Language dc:language

en

Repository record dc:identifier

https://openprairie.sdstate.edu/etd/509

OAI identifier oai:identifier

oai:openprairie.sdstate.edu:etd-1509