Date of Award

Summer 2019

Document Type

Open Access Dissertation


Marine Science

First Advisor

James L. Pinckney


Human activities have caused notable changes in ecosystems globally over the past century, which cause substantial ecological issues. The degree of these ecological issues is often investigated using the responses of bioindicator species. Bioindicator species often reduce their population densities and individual sizes as a response to the human disturbance. Observing these variations in the demographics is often an effective way to measure the strength of the ecological changes. However, they do not provide any mechanistic reason (s) for the shifts in the demographics, which is important for making predictions about responses of the species to the future conditions. Therefore, this dissertation employs an energetic approach to investigate the human disturbances on a bioindicator species, Ocypode quadrata. We show that O. quadrata populations alter their demographics as a response to the human disturbance, suggesting a reliable bioindicator for sandy shores. We also show that organisms alter their behavior based on the strength of the human disturbance, and these behavior changes are the energetic consequences of the human disturbance. We further show that human disturbance has a selective pressure on the morphology of O. quadrata. By combining field and laboratory surveys, we also show that habitat quality varies with relation to the strength of human disturbance and these habitats with lower quality influence the diet, physiology and reproductive potential of O. quadrata. Ultimately, this dissertation highlights the influences of human disturbance on ecology and physiology of a bioindicator.