Tom Walla, Ph.D.
University of Oregon
Office: Wubben 263
Phone: (970) 248-1146
Email: twalla@mesastate.edu
Courses
- Plant-Animal Interactions BIOL 406
- Tropical Field Biology BIOL 407
- Tropical Ecosystems BIOL 415
- Advanced Ecological Methods BIOL 405
- Insect Biology BIOL 331
- General Human Biology BIOL 101
Research Interests
My research interests are focused on understanding tropical ecosystems. Characterized by their exceptionally high species richness and awe-inspiring interactions, tropical forests present a special opportunity for biological investigation. Traditionally my work has concerned field projects designed to assess community structure and species diversity of the upper Amazon in Ecuador. Specifically I have been interested in characterizing species assemblages in space and time. For example, using nymphalid butterfly samples, my colleagues and I have clearly shown that canopy and understory faunas are distinctly different in terms of their composition. That is to say that there exist 'canopy species' and 'understory species' within the same forest habitat. Furthermore, the seasonal fluctuations of the two groups are temporally offset, with canopy species showing 'springtime' population explosions before those of the understory.
This study has also provided great insight for understanding the scaling of tropical butterfly communities. Collaborative work to this end has demonstrated the spatial scaling of these communities is ~1 kilometer, and that the lion's share of the spatial and temporal variance in population density exhibited by the community is due largely to differences among species as opposed to within species. This aspect of ecology has been little explored in the tropics and hold's great promise for future work.
Recently, my interests have turned to an exploration of insect-plant interactions in different tropical life zones. Specifically I am interested in understanding how interactions such as mutualism and parasitism vary across elevational gradients and climatic regimes. Preliminary work with ant-plant associations such as the Duroia / Myrmelachista association will form the foundation for future research in this field. What is the relative contribution of interactions to community structure under varying conditions of elevation, temperature and seasonality? These are the kinds of questions I hope to address in my future work here at Mesa State College and as a member of the Western Colorado Center for Tropical Research.
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