Date of Award
12-2021
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Wildlife and Fisheries Biology
Committee Chair/Advisor
Patrick Jodice
Committee Member
Beth Ross
Committee Member
Troy Farmer
Committee Member
Don Lyons
Abstract
Vagile organisms are expected to display movement behaviors that respond to a wide variety of both intrinsic and extrinsic factors. Identifying drivers of movement is fundamental to understanding the ecology of species, as well as implementing effective conservation measures. Technological advancements have allowed for the collection of fine-scale positional data at rapid temporal scales, which can be a powerful tool for assessing the movement behavior of tracked species and for understanding the potential fitness implications resulting from variations in animal space use. The goal of this dissertation was to identify important drivers of movement behavior and to describe the ecological outcomes of movement decisions in Eastern brown pelicans (Pelecanus occidentalis carolinensis) from the South Atlantic Bight. A total of 86 individual pelicans were outfitted with solar-powered GPS satellite transmitters in coastal South Carolina and Georgia, USA, from 2017 – 2020. Two cohorts of pelicans tracked during the passage of three tropical cyclones demonstrated a reduction in movement correlated with anomalies in barometric pressure and wind speed relative to ambient conditions, indicating a shelter-and-wait strategy for increasing survival during these extreme weather events. By measuring the concentrations of an environmental contaminant, poly- and perfluoroalkyl substances, in the eggs of pelicans from three colonies located near Charleston, South Carolina, I demonstrated that eggs contained relatively elevated concentrations of chemicals regardless of proximity to likely point sources. GPS tracking of adults from the same colonies further suggested that variations in urban habitat use for foraging adults during the breeding season were also not reflected in egg contaminant concentrations. In contrast, the relative risk to foraging adult pelicans of encountering surface oil from a ship-based spill near Charleston Harbor was significantly influenced by location, as demonstrated through the use of an oil spill modeling toolkit combined with pelican telemetry data. Finally, the partial migration strategy of brown pelicans in the South Atlantic Bight is likely maintained by the ontogenetic migration of their primary prey, Atlantic menhaden (Brevoortia tyrannus), and aligns with the fasting endurance hypothesis of partial migration. Understanding the causes and consequences of movement in brown pelicans in the South Atlantic Bight has important implications for the ecology and conservation of this species throughout their range.
Recommended Citation
Wilkinson, Bradley, "Ecological Outcomes of Movement Behavior in Brown Pelicans from the South Atlantic Bight" (2021). All Dissertations. 2941.
https://tigerprints.clemson.edu/all_dissertations/2941