Upper Hudson (green) and Upper Delaware watersheds (blue), and the streams of the Upper Delaware watershed found within Pennsylvania.
Plant community ecology
My primary research is in plant community ecology, focused on the diversity and species composition of the riparian zones of small streams. My study regions include the Delaware watershed (Pennsylvania) and other waterways of eastern Pennsylvania, as well as the Upper Hudson watershed (New York). I integrate field observational studies and greenhouse experimental approaches to understand what factors govern the organization of riparian plant communities and how they differ from nearby upland communities. I also use plant functional traits to help explain the composition of riparian plant communities and biological invasions in those communities.
River corridors may contribute to the spread of introduced species across the broader landscape, and invaders are often very common in riparian zones. In my current research, I try to understand why introduced species are successful in these habitats. In the past, I have also studied the distribution of the introduced plant Japanese knotweed (Fallopia japonica (Houtt.) Ronse Decr.) in streams of the upper Hudson watershed and the effects of allochthonous leaf input from this plant on in-stream macroinvertebrate communities. I have also worked on distribution and population biology of the invasive spotted knapweed (Centaurea stoebe) both in urban Long Island and in New York's Adirondack State Park.
Disturbance is a fundamental concept in ecology, but also an extremely broad one. In the context of riparian zones, for instance, the term disturbance could be used both to describe a natural flood event and to describe the complete loss of a flood regime following the construction of a dam upstream. My research interests include the role of multiple types of disturbances in structuring riparian plant communities and the synthesis of existing studies of disturbance into a common framework.
My conservation-related research addresses a variety of questions in applied conservation ecology, from both biological and policy perspectives.
In collaboration with Susan Tsang, I am also working on a project bridging theoretical and applied conservation biology in the islands of southeast Asia. We are developing models to more effectively designate currently occupied area by endangered flying foxes (Pteropus). Species ranges are often defined simply as the entire area of any islands on which these species are found, but in reality, many occupy very restricted habitats. We are working to identify more accurate ranges for these species. We are also using this group as a case study to incorporate strict habitat requirements into species-area relationship models.
In the past, I have worked on population modeling and development of effective conservation plans for endangered species such as the golden eagle (Aquila chrysaetos) and several North American bat species. I have also evaluated the effectiveness of existing conservation plans and critical habitat designations under the Endangered Species act through research synthesis methods.
Other recent projects
In collaboration with Dana Opulente and the Hittinger lab (UW Madison), I am investigating assemblages of yeast species found in different environments, correlations between metabolic traits and those environments, and trade-offs between metabolic traits.