Research Seminar, Tyler O’Keefe: Causes and Consequences of Large Seabird Aggregations on Floating Mariculture

The importance of how and why animals interact with environmental novelty continues to grow as pristine landscapes are increasingly reshaped by human activity. Floating mariculture operations (hereafter farms), a form of novel habitat that is expanding in North Carolina and around the globe, present an opportunity to examine how animals respond to specific human modifications of the natural environment. Seabirds often aggregate in large numbers on the structure provided by these farms, but the reasons behind their disproportionate utilization of these sites and the ecological consequences of concentrating avian biomass over the water remain unclear. Furthermore, the introduction of farms has not occurred in a vacuum, with the combined effects of sea level rise and shoreline development potentially contributing to aggregation size and prevalence. My research combines high-resolution camera trap imagery with water level data and other environmental overlays to discern how diel and seasonal variability in aggregation size are influenced by bird behavior and environmentally-driven shifts in the value of social information. These images are also used to estimate avian-derived nutrient loading over farms, thereby providing an example of a direct effect of avian attraction. Results to date establish that seabird aggregations at farms are persistent but seasonally dynamic and that farms are capable of rewiring seabird nutrient inputs by concentrating this consumer-mediated nutrient supply over the water. Forthcoming work will test the strength and scale of avian nutrient enrichment, quantify changes in the value of social information and the mechanisms underpinning this variability, and provide further insights into how human alteration of the terrestrial-aquatic interface affects seabird behavior.