PARENT SESSION
Poster Session #57: Invasive Species Ecology: Grasslands.
Thursday, August 8. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Monitoring plant invasions in protected areas: Why is it important to look at multiple scales? Linaria vulgaris in West Yellowstone.

Pauchard, Anibal^*,1,2, Alaback, Paul¹, Edlund, Eric¹, ¹ University of Montana, Missoula, Montana² pauchard@forestry.umt.edu

ABSTRACT- Invasive alien species are threatening protected areas worldwide. However, few attempts have been made to adequately monitor their advances and ecological effects in these complex landscapes. We have used a multiscale method to study the invasion of Linaria vulgaris, an aggressive perennial weed, in the interface between Gallatin National Forest and Yellowstone National Park over the past three years. We have found that L. vulgaris occurs in both natural and human disturbed areas and that its dispersion follows major human corridors. Populations appear clumped in the landscape and their effects on pristine areas seem to be minimal. However, at the stand scale vegetative patches of the species tend to be clustered during early stages of the invasion and become dispersed as the species occupies all suitable sites, outcompeting native plants. L. vulgaris patch density and average patch size increases with time, especially in early stages of invasion. At the patch scales we have found that patches maintain their ramet density and reproductive potential even in the larger and older patches, indicating a higher overall output of propagules. Our results show that L. vulgaris is an important threat to high elevation environments in the Rocky Mountains. A multiple scale method allowed us to evaluate the implications of this invasion from the patch to the landscape scale. This comprehensive approach could help to define management priorities and identify specific research needs.

KEY WORDS: plant invasion, protected areas, multi-scale method, Linaria vulgaris