Research

Broadly, I’m interested in how human actions affect ecosystems My current research projects fall under these areas:

Artificial light and stream functioning
Experimental lights added to a stream in Malcolm Knapp Research Forest.
Photo Credit: Nora Schlenker.

Artificial lights, such as streetlights, are ubiquitous in urban areas. However, the potential effects of artificial lights on the ecology of stream systems is just starting to be researched in earnest. Previously, I found that aquatic invertebrate drift is greatly reduced by light levels typical of urban areas. However, some researchers in Europe did not find a strong response by drifting invertebrates to the experimental addition of light to streams. Undergraduate researchers I have mentored, including an interdisciplinary research team and a thesis student, have found evidence suggesting that aquatic insects exposed to light for many generations may adapt to this disturbance.

I have plans to extend this research to look at aquatic insect behavior in a common garden, as well as to study hatchery versus wild salmonid responses to artificial light at night.  

Urban Phenology and Interspecific Interactions

Artificial light at night is just one of many stressors faced by stream organisms in urban areas. I am currently developing projects with collaborators that will tease apart how light interacts with changes to temperature and flow to alter the phenology and evolution of stream organisms. I would also like to understand how changes to all three of these cues might interact, or indeed may counteract one another, to change or maintain an organism’s phenology.

In addition to altering phenology, changes in temperature, light, and flow can also change interactions between species. It is possible that normally diurnal visual predators may have their niche expanded by the introduction of artificial light into their habitat. Increases to stream temperatures might give an advantage to one competing species, while a flashier flow regime may tip the balance in favor of another. Better understanding how anthropogenic changes to temperature, light, and flow interact will allow us to understand controls on biodiversity and ecosystem functioning in urban systems as well as potentially improving management of urban waterways.

Differential Response to Environmental Change in Hatchery and Wild Trout

It is generally accepted by both fisheries managers and many anglers in the western United States that hatchery salmon do not fare as well in poor ocean conditions compared to their wild counterparts. I am interested in understanding if this differential response holds up when looking at trout that remain in freshwater. Some of the questions I would like to investigate are: Do hatchery and wild trout use the same thermal habitats at the same times? Are there differences in the fitness of hatchery and wild trout under different environmental conditions? How common is hatchery genetic introgression in wild stocks and under what circumstances is introgression particularly high (or low)? Answering these questions would help fisheries managers and would also provide insight into how domestication alters an organism’s ability to deal with environmental change.

The Effects of Dam Management on Riverine Organisms and Communities
Looking downriver from the Pelton Round Butte Dam in the Deschutes River

For many years, river ecologists have pointed to the large temperature changes as well as hydrologic changes caused by dams as a factor that dam operators need to mediate. In response, large temperature mixing towers are increasingly being built so that water can be released from both the surface and lower levels of a reservoir to more accurately mimic the natural temperature regime of a river. However, their use can be highly controversial. Most research efforts on these systems has focused on water quality, salmon and resident rainbow trout, but I would like to study the effects of these mixing systems on native non-game fish such as sculpin to better understand how the towers have changed their population dynamics, behaviors, and interspecific interactions.