UBC Theses and Dissertations
The ecological consequences of evolutionary change in freshwater ecosystems Rudman, Seth Michael
Evolutionary change has largely been ignored in ecology because it has traditionally been considered too gradual a process to alter ecological patterns. Recent evidence that evolution can occur rapidly has challenged this notion. Understanding when evolution is likely to alter ecological processes and how evolution changes ecological dynamics could improve our understanding of community and ecosystem ecology and lead to greater predictability. In chapter 2 I present the results of an experiment investigating how local adaptation in two species alters community structure and ecosystem function. I found that intraspecific variation between these two taxa can interact to alter both the ecological community and some ecosystem functions. In chapter 3 I focus on understanding how rapid evolution from introgressive hybridization alters ecology in both a mesocosm experiment and a comparative field study. I found that introgressive hybridization lead to a phenotypic shift and predictable changes in community structure and ecosystem function based on trophic cascade theory. In chapter 4 I detail the findings from a large-scale piscivorous fish trophic cascade experiment. In this study I found that the addition of a piscivore alters the movement of invertebrates from aquatic environments to terrestrial environments. In addition, the results support previous findings that non-consumptive effects of predators may play an important role in determining the strength of the trophic cascade in the aquatic system. In chapter 5 I explore the role of rapid evolution in enhancing and maintaining ecosystem services. I create a quantitative criteria for assessing the importance of rapid evolution to ecosystem services, review cases where rapid evolution may already be playing an important role, and suggest ways to manage for the conservation of ecosystem services.
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