Documenting wildlife distributions along urban to rural gradients (URGs) creates opportunities to comparatively analyze wildlife habitat associations. In urban environments, wildlife diversity is expected to be impoverished and limited to invasive and generalist species while more diverse wildlife assemblages are expected in rural environments. Using motion-triggered game cameras I documented presence of the eastern gray squirrel (EGS), the coyote, and the white-tailed deer (WTD) along an URG in southeastern Massachusetts, to determine the effects of urbanization on their occupancy patterns. I used a multi-seasonal dynamic occupancy modeling approach to determine the overall occupancy probability of each study species along the URG. This model encompassed four parameters: (1) initial occupancy, (2) colonization probability, (3) extinction probability, and (4) detection probability. I hypothesized that the occupancy of each species decreased with increasing urbanization. To test this hypothesis, I deployed motion-triggered cameras across 27 sites that collectively represented an URG which radiated southward from the Greater Boston area with decreasing urban land cover. My survey period spanned across one year (January 2021 to January 2022) where a single sampling month represented a different season: January months for winter, April for spring, July for summer, and October for fall. Each photograph was annotated with species identification. The occupancy model revealed that species vary in their relative sensitivity to urbanization and their distribution and occupancy along the URG is variable and seasonal. Therefore, different species have variable distribution patterns across natural, semi natural, and culturally historic landscapes. Seasonality, percent imperviousness, and index of ecological integrity (IEI) remained either non-significant or marginally significant in predicting overall occupancy of each species through variable influences on initial site occupancy or persistence while human population density remained non-significant as a predictor of wildlife occupancy. Warmer seasons showed the greatest occupancy of the EGS and WTD, while colder seasons showed the greatest for the coyote. More imperviousness did not affect the occupancy of the EGS or WTD, but did slightly for the coyote. IEI was non-significant in determining EGS occupancy, while levels greater than 0.2 did not alter the occupancy of the WTD or the coyote. Identifying species’ adaptations to associate in urban and other cultural landscapes will help control their expansion and understand their ecological impacts both inside and outside their native ranges. In wildlife conservation, priority should be placed on the sites that offer the best food, protection, and environmental stimuli. Therefore, studying how urban habitats differ from rural habitats will allow for better understanding of the behavioral responses and movements of wildlife along the URG.
Dr. Thilina D. Surasinghe, Thesis Advisor
Dr. Christopher Bloch, Committee Member
Dr. Michael Graziano, Committee Member
Scully, Bobbi M.. (2022). Multi-species Multi-seasonal Wildlife Occupancy along an Urban-to-Rural Gradient in Southeastern Massachusetts. In BSU Honors Program Theses and Projects. Item 564. Available at: https://vc.bridgew.edu/honors_proj/564
Copyright © 2022 Bobbi M. Scully