Date of Award:

5-2017

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Wildland Resources

Committee Chair(s)

David N. Koons

Committee

David N. Koons

Committee

Christa P. H. Mulder

Committee

Karen Beard

Committee

Dan McNulty

Committee

Joe Wheaton

Abstract

The mean and variability of environmental conditions have changed as a result of human activity, and continued changes are predicted. The strongest effects on natural populations will often be channeled through species interactions, as shifts in species range limits and life cycle schedules will shift in relation to each other. These changes will often impact rates of survival, growth, and reproduction simultaneously, and these effects will likely differ across habitats.

In chapter 2, I used mathematical modeling and computer simulations to investigate the evolutionary significance of increasingly variable environments, and examine how evolutionary pressures change when multiple vital rates are affected simultaneously. I found that when multiple vital rates respond to a shared environmental driver, evolutionary selection pressures can be strengthened, weakened, or even reversed, adding an important dimension to existing life history theory.

In chapter 3, I examined whether snow goose sensitivity to climate differs between habitats, and whether these responses depended on the diversity of available plants. I found that geese were more sensitive to seasonal warmness in inland freshwater habitats where there are relatively few species of plants they consume, while they consistently produce relatively high numbers of offspring in coastal saltwater habitats.

In chapter 4, I constructed a population model to investigate the consequences of climate change for snow goose populations in coastal and inland habitats. I found that climate change will disproportionately improve population growth in inland areas, potentially offsetting management efforts to reduce currently overabundant populations.

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