Preston Lab - Research

Our research group studies the ecology and conservation of freshwater ecosystems. Current research themes involve:

Disease ecology, including drivers of parasite community structure and the roles of infectious agents in community dynamics, food webs, and ecosystem processes.
Causes and consequences of aquatic species invasions, with a focus on how invasion outcomes are influenced by other forms of environmental change.
Food webs and environmental change in freshwater streams, including how wildfires affect structure and functioning.
Ecology of high elevation aquatic ecosystems in the context of climate change.
Effects of urbanization of aquatic ecosystem properties and community structure.

Parasite Ecology – Parasitism represents the most widespread animal life-history strategy in nature. Parasites influence host traits and can regulate host population sizes, sometimes leading to significant effects on community structure and ecosystem processes. Recent projects have examined the roles of parasites in food webs and ecosystem processes within wetlands and streams. Current project are also exploring spatial heterogeneity in disease risk and the environmental factors that shape parasite community structure in freshwaters. Most of these projects have focused on trematode worms, which have complex life cycles where they infect hosts in both the aquatic and terrestrial environment.

Species Invasions – Invasive species have become major drivers of ecosystem change, a problem that is particularly prominent in freshwaters. Understanding the effects of invasive species, however, is complicated by the occurrence of multiple invaders simultaneously and concurrent environmental changes (e.g., climate warming, pollution, habitat alteration). Much of our research involving invasive species has examined the factors that mediate interaction strengths between invaders and native community members. For example, nutrient availability, habitat complexity and community structure have important roles in moderating invasive species effects within wetlands. We have also used ecosystem-level experiments to see how differences in experimental venue (e.g., laboratory enclosure, outdoor mesocosm, or natural wetland) alter experimental results. This work has focused mostly on invasive fish, amphibians and snails.

Wildfires and Stream Food Webs – The 2020 summer season experienced some of the largest wildfires in recent history. We recently started some new projects related to how fires in Colorado affect stream-riparian food web connections and in Oregon regarding fire effects on host-parasite interactions. The project in Colorado is addressing how fire affects the fluxes of aquatic insects into and out of streams, and what the consequences may be for trout. After the fires ended, rainfall caused significant amounts of ash to enter the streams, suggesting that the disturbance effects are still playing out in the first year after the fires. Our initial data suggests we will see significant changes in stream community structure and connectivity to the riparian habitat.

Trophic Interactions in Streams – Quantitative measures of species interaction strengths are central to understanding food web dynamics. We have conducted several projects in stream food webs in Oregon that involve quantifying species interaction strengths. This work involves stream predators (sculpin, trout, salamanders, crayfish) and their prey. We are also working to extend current approaches for measuring predator-prey interactions to host-parasite interactions in stream food webs. This work aims to assess the relative importance of predation versus parasitism in driving population dynamics of hosts, community structure, and eventually ecosystem processes.

Environmental Change at High Elevations – Alpine aquatic systems are particularly vulnerable to environmental change because they integrate ecosystem responses of the surrounding landscape through the movement of water. We have been examining how alpine lakes are responding to climate change in collaboration with researchers at the Niwot Ridge LTER. This work has emphasized how physical, chemical and biological responses of aquatic systems can show tightly coupled responses to climate warming.

Urban Aquatic Ecology – Urban growth has led to large numbers of aquatic ecosystems in and around most cities and towns. These ecosystems serve a range of important functions, including flood and pollutant mitigation. They also become colonized by a range of aquatic taxa, sometimes including species of conservation concern. Our work on urban aquatic habitats has focused on pond ecosystems in the Madison, Wisconsin area, where there are rich communities of fish, amphibians, reptiles, and invertebrates. This works aims to understand drivers of community structure to better inform management of urban waterbodies for ecosystem services and wildlife habitat.