Date of Award
2024
Document Type
Thesis
Degree Name
Master of Science (MS)
Department
Natural Resources
First Advisor
James D. Murdoch
Abstract
Coyotes (Canis latrans) underwent rapid geographic range expansion into the eastern United States in the 1900s and more recently into Cape Cod, Massachusetts. Coyotes are now locally common across Cape Cod and frequently in conflict with management activities. The objective of this study was to estimate coyote abundance/density and factors influencing their spatial distribution in Cape Cod National Seashore. We used noninvasive genetic sampling to collect DNA from scats through 8 surveys of 60 sites selected using a spatially balanced sampling design from October to December 2022 and May to August 2023. We identified individual coyotes using 12 microsatellite markers and a sex marker. We surveyed 360 km of transects (1.5 km per site) each year and collected 215 scats in 2022, of which 103 were successfully genotyped and determined to be from 57 individual coyotes. In 2023, we collected 213 scats, of which 83 were successfully genotyped and determined to be from 55 individual coyotes. We used genotype data to reconstruct coyote pedigrees and applied the Creel-Rosenblatt estimator to determine abundance/density. Pedigree reconstruction is an emerging approach that uses genetic data to infer the existence of unsampled individuals and can provide accurate abundance estimates. To estimate occupancy, we used a presence-only model to evaluate the effect of different land cover types on the probability of coyotes occurring in the landscape. Results indicate high genetic diversity (HO = 0.67) and low inbreeding (FIS = 0.05) for all coyotes sampled in 2022 and 2023, suggesting reasonable gene flow from populations elsewhere. Pedigree reconstruction indicated the presence of 81 individuals (± 10.2 SE; density = 0.46/km2) with higher precision compared to other common modeling approaches including Huggins closed capture (71 ± 11.2 SE) and spatially explicit capture-recapture (90 ± 13.9 SE). Occupancy across the landscape was high, and our top model indicated that the additive combination of proportion of forest cover (250 m radius), proportion of barren land (250 m radius), and distance to development most influenced occupancy probability. Effects of each covariate were positive. Altogether, these results demonstrate the utility of noninvasive genetic methods in a pedigree framework for estimating abundance at a landscape scale that can be used to inform management of this widespread, but elusive, large canid. They also suggest that coyotes in this landscape are not isolated and likely connected across the broader landscape and potentially into mainland Massachusetts where reported density is similar.
Language
en
Number of Pages
60 p.
Recommended Citation
Boudinot, Koryna, "Estimating coyote density and occupancy in Cape Cod National Seashore" (2024). Graduate College Dissertations and Theses. 1917.
https://scholarworks.uvm.edu/graddis/1917