I have worked on this component of my research the longest.  It is my goal to understand how speciose inputs of leaf litter to streams alters organic matter processing, detritivore foraging and performance, and other trophic interactions.  To date the work has generating many interesting results.  In particular, shredder foraging activity almost always results in the slowing of breakdown rates of leaf mixtures.  Currently, I am collaborating with researchers at Northern Arizona University and Virginia Tech to expanding this work to other forest types across North America.  In addition, students in my lab are beginning a series experiments to disentangle the relative effects of altering resource mixtures and predation pressure on consumers, and feedbacks on leaf decomposition.

Riparian Biodiversity & Stream Processes

Recent infestation by the hemlock woolly adelgid (HWA) from Asia has resulted in massive and chronic loss of Eastern Hemlock (Tsuga canadensis) from many stream margins.  Working with colleagues at the Appalachian Lab in Frostburg, MD and the University of Wisconsin Dept. of Forest Ecology & Management, I am currently looking into the role this invasive pest may have on stream material flux.  As stands of hemlock die, alterations in C and N fluxes are expected to change, moderated by in-stream processing by stream detritivores.

Alterations of Material Flux in Streams as a result of Hemlock Woolly Adelgid Infestation

Research

Department of Geography & Environmental Systems

With the widespread deployment of genetically-modified Bt corn for the management of European corn borer, leaves with the Bt proteins will likely enter streams and rivers. The impact of the Bt protein in flowing water systems is unknown.  Since these proteins are known to affect the survival of lepidopterans and coleopterans, it is possible that the aquatic insects may be impacted, especially those that are adapted for feeding on organic debris. Since these insects play a vital role in the breakdown of leaf material, the rate of in stream decomposition may be altered. Lab & field studies currently confirm the negative impact of Bt on stream insect activity, providing the foundation for extensive fieldwork currently underway with support from the U.S. Department of Agriculture Biotechnology Risk Assessment Grants Program.

Non-target effects of genetically modified crops: Bt corn detritus in streams

Students interested in pursuing a graduate degree in my lab should send me an email at Stream.Ecology@umbc.edu with a summary of your interests, GPA, GRE scores, and a CV.  More information about the graduate program is located on the Departmental website.

In collaboration with Dr. Kathy Szlavecz at Johns Hopkins University, I am extending my work on detritus-based food webs to forest soils.  Currently, Kathy and I are interested in how consumer vs. resource diversity alters rates of litter decay, and how this might interact with predator activity.  Since speciose leaf litter can alter foraging activity of consumers, predator presence and activity may change consumer feeding behavior, and thus leaf-litter breakdown.  Thus, we are taking a multi-trophic approach to understanding how the potential for species loss, either tree species or soil taxa, may impact ecosystem processes. 

We are conducting this work as part of the Baltimore Ecosystem Study LTER, and conducting our field studies adjacent to permanent soil plots established in Leakin Park, a large, urban forest remnant within Baltimore City.

Trophic Interactions in Urban Forest Soils