Invasive plant management on anticipated conservation benefits: a scientific Assessment

Authors: Sheley, Roger; James, Jeremy; Rinella, Matthew - Matt; Blumenthal, Dana; DITOMASO, JOSEPH - University Of California

Submitted to: United States Department of Agriculture Natural Resources Conservation Service
Publication Type: Government Publication
Publication Acceptance Date: 9/10/2011
Publication Date: 10/1/2011
Citation: Sheley, R.L., James, J.J., Rinella, M.J., Blumenthal, D.M., Ditomaso, J.M. 2011. Invasive plant management on anticipated conservation benefits: a scientific Assessment. United States Department of Agriculture Natural Resources Conservation Service. p.291-336.

Interpretive Summary: We used a comprehensive review of peer-reviewed literature to synthesize a summary discussion of the efficacy of various invasive plant strategies on several anticipated benefit. The literature documented only short-term vegetation responses to invasive plant management and rarely addressed secondary ecosystem responses to management. Our ability to protect not-infested lands is encumbered by the lack of early detection techniques and lack of effective eradication efforts once new infestations are identified. Herbicides provided short term control of most invasive weeds, but without additional management, weeds returned rapidly. Documentation of biological control’s influence on plant development is robust, but positive effects on control and vegetation dynamics are exceedingly rare. Grazing management is emerging as a useful method for directing vegetation dynamics, but the timing, intensity and frequency of grazing, as well as the class of livestock are only known for a few invasive weed species. Restoration of invasive plant infested rangeland is difficult and only successful about 20% of the time when non-native plant material is seeded and less where native species are seeded. There are cases where invasive plant management strategies can be effective, and in those cases, they appear to favorably affect wildlife and other important ecological attributes of the ecosystem. However, most strategies are associated with high ecological risks and high risk of failure in the long-term. It is clear from the literature that much research remains if the anticipated benefits of invasive plant management are to be achieved. This review indicates that long-term invasive plant management is lacking for most situations, and the need for ecologically-based invasive plant management is substantial and unmet.

Technical Abstract: Invasive plants negatively impact rangelands throughout the western United States by displacing desirable species, altering ecological processes, reducing wildlife habitat, degrading systems, altering fire regimes, and decreasing productivity. Assessing the influence of conservation practices on various perceived benefits to ecosystem properties provides a critical link to understanding their value toward establishing and maintaining sustainable ecological and economical systems. We used a comprehensive review of peer-reviewed literature to synthesize a summary discussion of the efficacy of various invasive plant strategies on several anticipated benefit. The literature documented only short-term vegetation responses to invasive plant management and rarely addressed secondary ecosystem responses to management. Our ability to protect not-infested lands is encumbered by the lack of early detection techniques and lack of effective eradication efforts once new infestations are identified. Some strategies for maintaining invasion resistant plant communities are beginning to emerge in the literature. Herbicides provided short term control of most invasive weeds, but without additional management, weeds returned rapidly. Documentation of biological control’s influence on plant development is robust, but positive effects on control and vegetation dynamics are exceedingly rare. Grazing management is emerging as a useful method for directing vegetation dynamics, but the timing, intensity and frequency of grazing, as well as the class of livestock are only known for a few invasive weed species. Restoration of invasive plant infested rangeland is difficult and only successful about 20% of the time when non-native plant material is seeded and less where native species are seeded. There are cases where invasive plant management strategies can be effective, and in those cases, they appear to favorably affect wildlife and other important ecological attributes of the ecosystem. However, most strategies are associated with high ecological risks and high risk of failure in the long-term. It is clear from the literature that much research remains if the anticipated benefits of invasive plant management are to be achieved. This review indicates that long-term invasive plant management is lacking for most situations, and the need for ecologically-based invasive plant management is substantial and unmet.