My research interests are broad but center on examining the determinants and consequences of species diversity at local, regional, and global scales. To date, my research has employed observational, field, computational, statistical, and GIS approaches to understand issues in community ecology, conservation biology, avian ecology, and invasive species. I involve undergraduate researchers to continue and expand my research interests.
Community structure and competition
I use null models and Monte Carlo simulations to examine the extent to which competition influences species’ geographic ranges. More specifically, I use presence-absence matrices to analyze the spatial distribution of birds on island archipelagoes and to test whether species exhibit exclusive distributions. Congeneric birds co-occur significantly less frequently than predicted, consistent with a competition hypothesis. However, when examined separately, most genera and guilds do not exhibit patterns that differ from random expectations. Furthermore, differences in habitat preference and barriers to dispersal are two alternate hypotheses that explain most exclusive patterns and are supported by available data. Distributional evidence alone does not implicate competition, and I argue that the range of conditions under which competition is likely to generate exclusive distributions across islands is narrow.
Radar technology and avian migration
Several students, a collaborator, and I are using radar data to understand patterns of avian migration along the Mississippi River. We use radar images (the same radar data that shows storm activity on the local news) to quantify the intensity of bird migration and to identify habitat patches that are used by migrating birds to refuel. We also aim to assess how migration differs between years and between seasons (spring vs. fall) and to compare radar-based patterns to field surveys.
With a team of collaborators and an undergraduate advisee, I have studied geographic patterns of song variation in the Dickcissel. I have also investigated the consequences of biotic homogenization for the loss of global biodiversity and how estimates of species richness from rarefaction are biased by nonrandom spatial patterns. With a team of collaborators, I have examined consequences of host plant genotypic diversity on species diversity and community stability of associated arthropods.
I plan to continue and expand my research to pursue three main questions: (1) How do land management practices impact the suitability of habitat for bird populations?, (2) What are the consequences of biological invasions for vertebrates?, and (3) Wha s the relative influence of species-level traits (e.g., morphology), site differences (e.g., resource and habitat availability), history, and species interactions (e.g., competition) in structuring local communities? I incorporate undergraduate students, field studies, and computational methods into a research program to address these exciting questions and to build a research program in avian conservation biology.
Because my research interests require a diverse set of skills, undergraduate researchers with varying interests could participate in my research program (see Opportunities[hyperlink]). Possibilities exist for field research, laboratoryexperiments, GIS approaches, and computational and quantitative biology. My collaborative research program broadly trains undergraduate researchers in avian ecology.