US Forest Service Research & Development
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  • US Forest Service Research & Development
  • 1400 Independence Ave., SW
  • Washington, D.C. 20250-0003
  • 800-832-1355
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Dean E. Pearson

Research Ecologist
800 Block East Beckwith
United States

Phone: 406-542-4159
Contact Dean E. Pearson

Current Research

1) I conduct basic research in community ecology to understand how communities are structured. This information provides a baseline for understanding how to manage systems and for developing realistic management and restoration targets. One example includes large-scale predator, ungulate, and rodent exclusion work in the Blackfoot Valley of western Montana.2) I conduct research on biological invasions to try to understand the causes and consequences of invasions in order to better manage this problem. This involves three components:a. international research focused on determining the causes of invasions by examining the biogeographic basis of invasions, i.e., comparing invaders in the native and introduced ranges (current studies include Turkey, Argentina, Germany, California, and Montana),b. studying the processes of invasion and impacts of invaders in the introduced range, including the ecological and evolutionary response of natives to invaders,c. studying the efficacy of management tools for mitigating invader impacts (e.g., biological control and herbicides).

Research Interests

My primary research interest is to advance community ecology through studies of biological invasions and to use this information to improve invasive species management. Biological invasions serve as grand natural experiments that provide unique opportunities to view the processes that structure ecological communities. Even in the most recently assembled natural communities organisms have had hundreds or thousands of years to interact and sort themselves into the modern assemblages we see. This makes it very challenging to identify the relative roles of competition, predation, parasitism, resource availability, etc. in structuring extant communities. However, with biological invasions, it is possible to observe these processes in real time as a novel organism invades, establishes, and dominates (in the case of strong invaders) a new assemblage. It is also possible to see how the assemblage finally settles into a new equilibrium state as the invader's dominance wanes through the ecological and evolutionary adaptation of the community to its presence. Newly hypothesized understandings of these processes can then be tested in the context of directed community assembly through the applied largescale natural experiments that are attempts to manage the invasion problem, for example, classical biological control - the intentional introduction of exotic organisms to manage invasions. Thus, biological invasions offer an opportunity to advance understandings of community ecology that can in turn be tested by applying these understandings to the management of the invasives problem.

Past Research

Biological invasions present the second greatest threat to natural ecosystems and the services they provide next only to actual land transformation. Exotic species invasions cost the United States 120-140 billion dollars per year in revenue losses and mitigation costs. Magement of this problem has been particuarly challenging due to a lack of understanding of the fundamental processes underlying invasion. My research attempts to better understand the causes and consequences of invasion and the efficacy of current managmen tools in order to better guide management approaches toward more effective mitigation. Success in these efforts offers tremendous benefits in terms of US revenues and stability of ecosystem services.

Why This Research is Important

I have conducted research in wildlife habitat relationships pertaining to small mammals and America marten. I have conducted research related to a variety of methodological approaches in wildlife such as sampling forest carnivores using remote sensing cameras, smoked tracking plates and snowtracking, small mammal trapping techniques, and population estimation.


  • University of Montana, Organismal Biology and Ecology , 2005
  • University of Montana, Zoology , 1995
  • University of Montana, Wildlife Biology , 1992

Featured Publications & Products


Research Highlights


Why Do the Exotics Beat the Natives: Where Is the Home-Team Advantage

New research sets forth a framework for understanding why exotic plants invade and how to fight the invasions


Last updated on : 06/01/2015