Economic impacts of invasive plants

Invasive plants, by definition, have negative impacts on native ecosystems. In many cases, they also have negative impacts on ecosystem services -- such as water supply, flood protection, power generation, fire protection, and recreation -- and on agricultural production through range and timber lands. Putting an economic figure on these impacts is difficult, but such figures are important for informing major programmatic decisions, especially those decisions involving funding for invasive plant management programs. Existing estimates, especially those from David Pimental of Cornell University with others, serve as a benchmark for overall impacts, but are very coarse and typically use management expenditures as a proxy for actual impacts. Other studies are more detailed, but only address a single specific impact (see list at CIPM http://www.weedcenter.org/inv_plant_info/impacts.html). NNRIPC will work toward aggregating information on impacts, and generating detailed estimates for overall economic impact from invasive plants in the U.S. to inform national decision making.

Doug Johnson
California Invasive Plant Council
January 22, 2009