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University of Florida (2020)

The Role of Patch- and Landscape-Level Processes in Shaping Desert Rodent Communities

Bledsoe, Ellen

Titre : The Role of Patch- and Landscape-Level Processes in Shaping Desert Rodent Communities

Auteur : Bledsoe, Ellen

Université de soutenance  : University of Florida,

Grade : Doctor of Philosophy (PhD) 2020

The field of community ecology focuses on when and where we find interacting groups of species, why those species are present at a given location or time, and how the interactions between species affect species diversity in the ecological community. In my work, I am particularly interested in the interaction of these local- and landscape-scale processes and the threshold at which the patterns and processes at one scale or the other are more likely to drive the community patterns that we see.

To ask questions about the interactions between the patch- and landscape-level processes, we can leverage time-series data. In particular, time-series data collected for multiple patches allows us to capture the spatiotemporal nature of the pivotal processes contributing to metacommunity dynamics. For my dissertation, I use data from the Portal Project, a long-term experimental site in southeastern Arizona with over four decades of small mammal capture-mark-recapture data. The site consists of 24 50m x 50m fenced plots which are designated as controls, full rodent exclosures, or kangaroo rat exclosures (only the Dipodomys spp., a behaviorally dominant genus, are excluded). Rodent trapping occurs monthly year-round and plant censuses twice yearly.

Each chapter of my dissertation can be thought of as a case study—leveraging a different aspect of the Portal Project data—to ask questions about the role of local- and landscape-scale ecological processes and how they interact. My second chapter directly investigates local-scale coexistence among the rodents at Portal and, in particular, whether species at the site shift their diet based on the presence or absence of the behaviorally dominant competitor, a well-known ecological concept that has been challenging to demonstrate conclusively. My next chapter focuses on the interaction of local- and landscape-level processes to understand how the arrival of a new species of rodent to the site affected how other rodent species in the system perceive the quality of the landscape. In my fourth chapter, I present a framework for how different drivers (e.g., primary productivity) affect the timing and abundance of transient, or intermittently present, species in a system.

Présentation (ProQuest)

Page publiée le 13 juin 2021