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Email: chparadise@davidson.edu
The role of abiotic factors in the organization of communities is one of the most fundamental questions in ecology. Heterogeneity of abiotic factors has been hypothesized to alter the outcome of biotic interactions and influence top-down and bottom-up factors. Additionally, the relative importance of top-down vs. bottom-up factors is a prominent debate in contemporary ecology. I am interested in how biotic interactions are mediated by abiotic factors, and how changing interactions may affect community structure. I am especially interested in the role resource availability plays in dynamic interspecific interactions. I use a variety of approaches to investigate these concepts, from whole community field monitoring to manipulative field and laboratory experiments on single species and subsets of communities.
One bottom-up factor that may be critical to forest aquatic systems is energy input in the form of leaf litter. Treehole habitats, the system I have been studying, are easily manipulated forest aquatic systems that occur as small, discrete habitats and thus make excellent model communities to study effects of resources and abiotic factors. Leaf litter forms the basis of a processing chain wherein resources change condition over time and consumers specialize on resources in different condition. Consumers may therefore play a role in determining resource abundance, thus having an important community-wide influence. One outcome of processing chains is a commensalism, where "upstream" consumers break down the resource, thereby providing resources in another form to "downstream" consumers. The interaction involves organisms in the middle of the food web that are affected by bottom-up forces, but in a way that is modulated by lower-level consumers.
The study of these and other detritus-based communities is relevant to questions of general ecological importance, as well as to questions regarding responses to changing environments. In the future I plan to continue investigating the effects of resources and abiotic factors on biotic interactions and community structure, using a variety of detritus-based communities. I am specifically interested in examining the prevalence of processing chain commensalisms in these communities, and the relationships of processing chain commensalisms to resource levels and abiotic factors, as well as the possibility that upstream consumers can affect the whole community as keystone species.
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Page last updated by Chris Paradise on 1 January 2007