Date of Award

5-1-2024

Document Type

Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

Scott Parker

Second Advisor

Lindsey Bell

Third Advisor

Jesse Rouse

Additional Advisors

Thomas Rainwater

Abstract

Raccoons (Procyon lotor) are a dominant predator of American alligator (Alligator mississippiensis) nests in the southeastern United States, using a combination of olfactory, visual, and tactile cues to identify nest locations. Studies on alligator nesting ecology typically require researchers to create paths through marsh habitat, potentially introducing visual and olfactory cues raccoons may use to locate nests. The purpose of this study was to evaluate the effect of human visitation to alligator nests on the frequency of raccoon nest predation at two sites in coastal South Carolina, Tom Yawkey Wildlife Center (TYWC) and Santee Coastal Reserve (SCR). We hypothesized that human foot traffic associated with nest monitoring increases the frequency of nest predation by raccoons. We observed a non-significant trend toward higher predation of foot-visited nests compared to drone and non-visited nests independent of study site (Mehta and Patel, p=0.261). This trend was similar at both study sites (Mehta and Patel, TYWC p=0.106, SCR p=1). When comparing predation by nest access method (i.e. boat, drone, foot, no-access), there was an overall non-significant trend towards higher predation of foot-visited nests independent of study site (Mehta and Patel, p=0.255). TYWC experienced higher predation of foot-accessed nests (Mehta and Patel, p=0.031) while SCR experienced lower predation of foot-accessed nests (Mehta and Patel, p=1). These results suggest that at sites of long-term nesting research (e.g., TYWC), alternative access methods may be useful in mitigating olfactory or visual cues left by researchers. Post-hoc power analyses, however, indicate low statistical power for our comparisons (Nest Predation by Treatment Group: 33.15%, vs Nest Predation by access method: 29.62% predation). Overall, the results of this study suggest raccoons may use human cues to locate alligator nests; however, replication of the study across multiple seasons to increase sample size would help to further examine this hypothesis.

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