Natural selection, in its most basic form, is described as a process in which traitsincrease or decrease in frequency depending on their fitness, and only the trait withthe highest fitness will remain in the population. Yet, populations rarely have asingle `optimal' trait. The way natural selection maintains this observed variationwithin...
A central theme of ecology is determining factors that influence species distributions. Within aquatic ecology, species present in flowing waters are primarily influenced by the natural flow patterns of the stream (natural flow regime paradigm) while explanations of species present in standing waters are further divided by habitat type. To...
Chapter 2:
Aquatic macroinvertebrate communities have been shown to exhibit strong differences between erosional (riffle and run) and depositional (pool) macrohabitats of streams. A subset of these communities are aquatic insect taxa that are an important food source for riparian consumers like birds, bats, lizards, and spiders. Understanding the role...
My thesis explored the effects of environmental variability on population
dynamics and community composition of aquatic insects. Environmental variability in
the form of flow regime in streams can limit the distribution and life-history traits of
aquatic insects. I used tributaries to the McKenzie River in Oregon with dramatically
different flow...
Although it is generally assumed that the intensifying abiotic environment is the primary effect of drought on aquatic organisms, drought-induced top predator extinctions may be an important underlying mechanism. I used manipulative experiments to disentangle the impacts of drying and top predator extinctions on arid-land aquatic invertebrate communities. I then...
The United States of America and the world are faced with three massive intertwining challenges at this time: COVID-19, racial inequity, and climate change. As a species, humans must come together and collectively address these challenges to preserve our humanity and make our world a more just and livable place...
Local aquatic insect diversity and community structure is the result of multiple local and regional factors, and observed patterns depend upon the spatial and temporal scale under examination. Isolated stream systems in arid regions represent a new challenge in understanding the drivers of diversity and community structure, as most studies...
Over 150 years ago, C. Bergmann observed a within-species pattern of increasing body size as elevation and latitude increased. Bergmann’s data came from numerous endothermic taxa, but the pattern has since been documented among numerous poikilotherms and invertebrates. The ferocious waterbug Abedus herberti Hidalgo (Hemiptera: Belostomatidae) lives in isolated populations...
Floods are major disturbance events for riverine ecosystems, directly and indirectly impacting organisms and their habitat. In this study I investigated the role of riverine floods and flow alteration in regulating aquatic macroinvertebrate population and community structure. I examined this problem using a variety of methods: a meta-analytic review of...
Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional processes; these processes act as filters that reduce the regional species pool down to the observed local community. In...