WWETAC Projects

Project Title: Applying population ecology to strategies for eradicating invasive forest insects

Principal Investigators: Andrew M. Liebhold, USDA Forest Service, Northern Research Station; Deborah G. McCullough, Depts. of Entomology and Forestry, Michigan State University


Collaborators and Affiliations: Eastern Forest Environmental Threat Assessment Center (EFETAC); National Center for Ecological Analysis and Synthesis (NCEAS)

Key Issues/Problems Addressed:

Biological invasions are an increasing threat to the function and diversity of ecosystems. Principles of population ecology may play a crucial role in establishment/spread of non-native species, yet use of these principles in management strategies for biological invasions is lacking.

Setting and Approach:

Allee effects (increase in birth rate with increase in population density -- positive density dependencies) create thresholds of population size below which populations decline to extirpation. This study assessed how Allee effects may be integral in risk assessments and resource allocation prioritization for non-native and invasive species management.  Specific tactics that may strengthen an existing Allee effect or create new ones were evaluated for possible application in biological invasion management.  

Key Findings:

Reducing populations below Allee thresholds, in some situations, may eradicate non-native/invasive plants without further intervention


Strategies that effectively exploit positive density dependence, such as Allee effects, may be a helpful tool for management of biological invaders.


Tobin, P. C., Berek, L., Liebhold, A. M. 2011. Exploiting Allee effects for managing biological invasions. Ecology Letters 14:615-624. (PDF, 295 KB)

Suckling, D. M., Tobin, P.C., McCullough, D.G., Herms, D. A. 2012. Combining tactics to exploit allee effects for eradication of alien insect populations. Journal of Economic Entomology 105: 1-13. (PDF, 476 KB)

Blackwood, J. C., Berec, L., Yamanaka, T., Epanchin-Niell, R. S., Hastings, A., Liebhold, A. M. Bioeconomic synergy between tactics for insect eradication in the presence of Allee effects. Proceedings of the Royal Society B (in press)

WWETAC Project ID:  FY08JB46