Connecting campuses to promote excellence in math and science


Vincent Eckhart

Grinnell College
The 'anatomy' of a species’ geographic range
All organisms have geographic range limits. To understand why those limits occur where they do requires identifying limiting factors that apply across spatial scales—from the positions of individuals to the geographic borders of entire species. At all scales, constraints on opportunity (limits to reaching unoccupied areas), environment (differences in conditions and resources between occupied and unoccupied areas), and adaptation (abilities to survive and reproduce—and to evolve improved survival and reproduction—in different environments) are expected to define distributions. What are the relative contributions of these constraints? Do large-scale distributions follow from small-scale controls, or are limits largely uncoupled across scales? This talk is about research to address the above questions, using as a model system the California plant, Clarkia xantiana, in the Sierra Nevada. Since 2005 I have worked with Grinnell students and with collaborators from other schools in comprehensive studies of limits to geographic range, across multiple spatial scales, integrating field experiments, modeling, and long-term monitoring of population biology and climate. I can't talk about all the published and unpublished work, but I can describe the developing story of why this species occurs where it does, rather than somewhere else, and what our findings imply about the general causes of current and future species distributions.
Related File: file368
Apply for monies for this speaker