Mark A. Davis

DeWitt Wallace Professor of Biology
Macalester College
1600 Grand Avenue
St. Paul, MN 55105
651-696-6102 (Fax:651-696-6443)

CV Publications UFIs (Useful Flyers of Information for Students)

I am DeWitt Wallace Professor of Biology at Macalester College.  I have been a faculty member at Macalester since 1981.  I am currently teaching three courses, Ecology, Field Botany, and Animal Behavior and Ecology.   Most of my current research, writings, and presentations focus on the ecology of introduced species and the field of invasion biology.

My current field research in the area of invasion biology involves a long-term study of the ecology of garlic mustard, Alliaria petiolata, an introduced forest herbaceous species reputed to cause great harm to native plants.  I have conducted this research with the collaboration of two Macalester colleagues, Jerald Dosch and Mike Anderson and more than twenty five Macalester students, a few of whom are shown in the photo to the left.  We began this project in 2010 at the Macalester College field station, the Katharine Ordway Natural History Area, located in Dakota County, MN.  To date, we have not been able to find any evidence of harm to native species.  In fact, the best predictor of garlic mustard presence in the oak woodland study site is high species richness of native plants, with garlic mustard being more likely to be present when there are many native plant species present.  We have reported these results in three journal articles in 2012, 2014, and 2015 (see Publications link above).

In 2000, using insights gained from succession ecology, Philip Grime, Ken Thompson, and I developed a new theory to explain community invasibility. Presented in the Journal of Ecology (Davis et al. 2000), the Fluctuating Resource Availability Theory of Invasibility predicts that a plant community will become more susceptible to invasion whenever there is an increase in the amount of unused resources. This theory rests on the simple assumption that an invading species must have access to available resources, e.g., light, nutrients, and water, and that a species will enjoy greater success in invading a community if it does not encounter intense competition for these resources from resident species.  This paper has been cited more than 2000 times. 

 In 2009, Oxford University Press published Invasion Biology, a book I wrote on the subject of biological invasions and the development of the field of invasion biology.  In 2011, Nature published an essay I and 18 coauthors wrote, titled Don't Judge Species on Their Origins.  This essay elicited vigorous discussion within the field of ecology, discussion which continues today, as illustrated by the more than 400 citations it has received since its publication.