Mark Davis


I am DeWitt Wallace Professor of Biology Emeritus at Macalester College.  I am an ecologist and taught at Macalester for 36 years, 1981-2017.  I came to Macalester with broad interests, including not only ecology but also plants and animals.  I was fortunate to be able to teach in all my areas of interest.  I taught Ecology, Field Botany, Animal Behavior and Ecology, and Conservation Biology.  The best part of teaching at Mac was being able to teach and interact with very smart and very interesting students.  One of my great joys was turning students on to plants and animals, especially birds.  My main memories are of the time I spent with students, both in and outside the classroom, including the hundreds and hundreds of field trips we went on, especially the annual Fall weekend trips to the Wilderness Field Station in northern Minnesota (1982-1999) and the annual Spring weekend trips to the Sand Lake National Wildlife Refuge in South Dakota and later to the Lac Qui Parles State Park in western Minnesota (1982-2017).  I was very fortunate to have spent my entire career at Macalester.

During my career, my research has included the study of insects, mammals, birds, and plants.  I could not have done most of this research without the assistance of dozens of Mac students.   I conducted my research both at the Macalester field station, the Katherine Ordway Field Station in Inver Grove Heights, MN and at the University of Minnesota's research station in East Bethel, MN, the Cedar Creek Ecosystem Science Reserve.  Much of my research, writings, and presentations have focused on the ecology of introduced species and the field of invasion biology.  

In 2000, using insights gained from succession ecology, colleagues 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 4000 times. 

 In 2009, Oxford University Press published Invasion Biology, a book I wrote on the subject of biological invasions and the history 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.