干旱区生态环境知识资源中心

Saltcedar invasion has many economic and environmental effects, including displacement of native riparian vegetation and associated wildlife. A biological control program led to the approval in 1994 of two insects for introduction but was delayed by the presence of the endangered southwestern willow flycatcher (SWWF) in saltcedar. In 2001, the saltcedar leaf beetle was released in six states but not where the SWWF was present. Delays circumvent the benefits that saltcedar suppression could have for other declining species, including many rare or absent in ecosystems dominated by saltcedar. Numerous birds forage within saltcedar vegetation but in lower numbers and diversity than in native stands that provide better habitat and insect resources. Successful establishment by saltcedar leaf beetle resulted in extensive saltcedar defoliation, and observations of wildlife feeding on the beetles in an otherwise depauperate system suggest that biocontrol may enhance habitat quality for many species, including the SWWF Consideration of the multiple species affected by saltcedar would have allowed more effective invasive plant management in this case, but delays also reflect drawbacks in federal administrative structures related to invasive species management in,natural areas' as much as problems with a narrow focus on a single species. A functionally integrated approach where research and management decisions are made cooperatively would allow more rational management of invasive species in wildland ecosystems.