Year of Award

2017

Document Type

Dissertation - Campus Access Only

Degree Type

Doctor of Philosophy (PhD)

Degree Name

Wildlife Biology

Department or School/College

College of Forestry and Conservation

Committee Co-chair

Winsor H. Lowe, Michael K. Schwartz

Commitee Members

Jeffrey M. Good, Kevin S. McKelvey, Michael K. Young

Abstract

Linking processes and patterns that occur over different scales is an outstanding problem in ecology and evolution. To establish this link it is critical to sample across scales. Here, I focus on two different types of scales: Evolutionary and spatial. In the first case, I explore the poorly understood role of competition between distantly related taxa in adaptive evolution. I argue that our current understandings may be biased by taxonomically-constrained studies that fail to consider potential species interactions between distantly related taxa. In the second case, I use a high-resolution, large-scale dataset to understand dynamics of competition between two aquatic animals of special conservation concern. This dataset contrasts with the data available for most species for which occurrence is often only known at a coarse resolution, which may limit our ability to understand the ecological drivers of species distributions.

In this dissertation I argue that an important limitation to sampling across evolutionary and spatial distance has been logistical. Sampling that is both intensive and extensive is expensive. To help overcome this challenge, I develop environmental DNA (eDNA) sampling tools that use genetic material in the environment (e.g., water) to non-invasively infer species presence. I develop protocols for single-species detection of animals in rivers that are substantially less labor-intensive and expensive than traditional sampling approaches. Further, I test approaches to expand this work into multi-taxa analyses using high through-put sequencing to efficiently sample for a suite of distantly related taxa.

In the final chapter of this dissertation I apply these eDNA sampling tools to understand habitat-mediated competitive outcomes between native, ESA-listed bull trout (Salvelinus confluentus) and invasive Eastern brook trout (Salvelinus fontinalis) in cold, headwater streams. High density sampling (1 km resolution) across a large spatial extent (630 sites) reveals that brook trout tend to exclude bull trout from smaller streams, effectively reducing the availability of cold water habitats which represent critical spawning and rearing habitat for the species. This is particularly relevant for the conservation of bull trout as stream flow and the availability of cold water habitat is expected to decline with climate change over the next several decades.

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© Copyright 2017 Taylor Matthew Wilcox