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Guidelines for use This presentation was created by staff of The Nature Conservancy's Wildland Invasive Species Team. It describes many of the consequences of non-native plant species invasions in wildlands. If you use this presentation unaltered, please include the first page which gives us credit for creating the presentation. If you alter the presentation, please note during your presentation (either verbally or by a slide) that your presentation is based on one created by our team. The images in this presentation were produced either by our team, were given to our team for our own use, or were provided for this slide show by www.invasive.org. They may be used in other presentations. However, anyone who wishes to use these images for other web sites or for publication must contact our program to discuss image rights. This slide can be removed before you present the show.
Understanding the impacts of invasive plants in natural areas John M. Randall The Nature Conservancy Wildland Invasive Species Team University of California, Davis http://tncweeds.ucdavis.edu May 2003 - v. 1.1 -
"On a global basis...the two great destroyers of biodiversity are, first habitat destruction and, second, invasion by exotic species” - E.O. Wilson
1998-1999 Survey of The Nature Conservancy field staff • 110 TNC staff from 50 states responded • 49% said INVASIVE PLANTS were among the top 3 threats • 84% said INVASIVE PLANTS were among the top 10 threats • Only 5% said INVASIVE PLANTS were not a problem • 271 INVASIVE PLANT taxa were reported
WEED EXOTIC ~ ALIEN ~ NON-NATIVE ~ NON-INDIGENOUSINVASIVENOXIOUS
Conservation GoalsConservation Targets(What are you managing for?)
Ecosystem Level Impacts- Disturbance regimes (i.e. fires) - Hydrology - Geomorphological processes (i.e. erosion, sedimentation) - Soil chemistry (i.e. nutrients) • Community and Population Level Impacts - Vegetation structure - Community composition - Resource competition - Negative impacts on native animals - Promotion of non-native invasive animals - Population reductions, eliminations - Reduced recruitment of natives (succession) - Hybridization with native species • Positive Impacts • Lack of Impacts
Ecosystem Level Impacts • Disturbance regimes (i.e. fires) • Hydrology • Geomorphological processes(i.e. erosion, sedimentation) • Soil chemistry (i.e. nutrients)