Date of Award

Spring 1-1-2016

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Ecology & Evolutionary Biology

First Advisor

Kendi Davies

Second Advisor

Brett Melbourne

Third Advisor

Carol Wessman

Fourth Advisor

Robert Guralnick

Fifth Advisor

Dan Doak

Abstract

One of the most immediate and consistently documented effects of forest fragmentation is an increase in solar radiation at newly created edges, resulting in higher and more variable temperatures within remnant habitat patches. However, few studies address altered thermal conditions as a mechanism driving ecological change in fragmented landscapes, despite the understanding that fragmentation changes temperature, and that temperature strongly influences the behaviour, physiology, and interactions of animal species. The goal of my dissertation research was to tease apart the role of temperature change in ecological responses to forest fragmentation. I first developed a conceptual framework that integrates thermal biology into fragmentation research to better predict and understand species, community, and ecosystem-level responses to habitat fragmentation. I then applied this framework to two field studies. First, I used a morphometric analysis to provide some of the first evidence that fragmentation can lead to significant declines in body size in ectothermic organisms through its impact on thermal conditions. Second, I used species distribution models to show that thermal conditions, particularly thermal stress experienced at a site, provide even larger constraints on ectotherm distribution in fragmented landscapes than some of the main effects of fragmentation, including patch size and proximity to patch edge. These field studies center on a small, ground-dwelling lizard species (the common garden skink, Lampropholis guichenoti) within the long-term, large-scale, controlled, and replicated Wog Wog Habitat Fragmentation Experiment. Together, these results demonstrate that temperature changes following fragmentation can have ecologically important impacts on organisms in remnant patches. Moreover, these results underscore the need for research efforts targeting temperature as a driver of ecological patterns in fragmented landscapes. Fragmentation remains one of the greatest contributors to biodiversity loss worldwide. Thus, understanding the future of global biodiversity relies on understanding the full spectrum of fragmentation’s impacts.

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