Luke R. Wilde

Date of Award

Spring 2021

Document Type

Open Access Dissertation

Department

Biological Sciences

First Advisor

Nathan R. Senner

Abstract

Organisms in dynamic environments must continually reassess the cost-benefit trade-offs of their interactions and adjust their behaviors accordingly. Nevertheless, ecological research often takes a ‘snapshot’ approach to studying interactions across sample locations and timepoints. Investigating ecological interactions in this way can miss important information about the influence spatiotemporal context has on the scale and direction of their effects. Longitudinal studies that follow individuals can elucidate how changing contexts affect an individual’s ecology while deepening our understanding of adaptive behavior. However, determining how context influences the effect of an interaction requires it be measured across a range of spatiotemporal conditions. Studying an animal’s ecology during periods of rapid change, such as early life development, could be a means of observing an interaction across multiple contexts on a short timescale. As animals grow, their susceptibility to predators, their foraging efficiency, and their energetic needs change because of their increasing body size and life experience. Studying species during early life therefore provides a tractable way to observe how animal behaviors change spatiotemporally. I studied Hudsonian godwit (Limosa haemastica) chicks in southcentral Alaska to learn how variable predation risk and resource demands affect their movements and early life survival. In my first chapter, I quantified the effect of stage-specific predation by colonial mew gulls (Larus canus) on godwit grouping decisions. Gulls provide umbrella protection for godwit nests but are the main predator of young godwit chicks. I found that by adjusting their association with gulls according to spatiotemporally variable predation risk, godwits optimize the trade-offs of grouping with gulls during chick development. Then, in my second chapter, I found that the effects of resource availability changed throughout godwit development, whereby low-quality resources have stronger effects on a chick’s survival as they grow larger. Further, I demonstrate that accounting for a population’s age-structure strengthens the link between resource availability and reproductive success by accurately modeling a consumer’s energetic needs. Together, my research underscores the importance of spatiotemporal context on ecological interactions and illustrates how studying intraindividual variation can deepen our understanding of the processes affecting animal behavior and population dynamics.

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© 2021, Luke R. Wilde

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