Dr. Alycia Stigall, Ohio University Left to right: Nikki Dudei, Brad Walls, Alycia Stigall, and Rob Swisher

My research:

My research focuses on understanding the interaction between evolution, specifically speciation and extinction events, and ecology and biogeography. In particular, I am using quantitative methods to assess the geographic ranges of individual fossil species across multiple time slices to compare how the boundaries of their ranges change during intervals of environmental change or following episodes of species invasions. Biogeographic changes are also examined in the context of species-level phylogenetic hypotheses (evolutionary trees). I am particularly interested in constraining the long-term impacts of invasive species during biodiversity crises, including the Late Devonian Mass Extinction and the Late Ordovician Richmondian Invasion. The introduction of non-native species by humans is an enormous problem in modern ecosystems, but similar events have happened in the geologic past from natural causes, such as sea level rise. By studying the ecological, evolutionary, and biogeographic effects of ancient invasions, we can better constrain the long-term effects of invasive species on biodiversity change, a topic of concern for mitigating the modern biodiversity crisis.

Working with the CMC collections:

The rocks in the Cincinnati region record a major invasion event, the Richmondian Invasion, and the specimens of the Cincinnati Museum Center collections are the best documented fossil collection of this event. My students and I are using CMC specimens to constrain the biogeography of this invasion in two ways. First, the CMC specimens are a wonderful set of beautifully preserved and well prepared fossils from which we can train to identify fossil species in the field. Secondly, each specimen in the collections contains stratigraphic and locality data that we can use to map species occurrences at discrete timelines throughout the Cincinnati region. Each of my students, Brad Walls, Nikki Dudei, and Rob Swisher are focusing their MS theses on different time slices of these rocks, before, during, and after the Richmondian invasion, respectively. Studying specimens at the CMC allows us to both learn to recognize our species faster and to determine areas of the outcrop belt that are undersampled to focus our field efforts-- and ultimately provide additional specimens for the CMC collections.

Friday, April 25, 2008