Distribution and ecology of exotic plants in Wrangell-St. Elias National Park and Preserve, Alaska

Abstract

The distribution of exotic plants and site factors influencing their abundance on roads and trails were studied in Wrangell-St. Elias National Park and Preserve during the summer of 2003. Seventeen species of exotic plants were found in the park at 173 locations. The most common species (Taraxacum officinale, Plantago major) were present at all study sites, while some (Trifolium spp., Bromus inermis, Leucanthemum vulgare) were restricted to specific disturbance types and particular areas. Though sampling was limited to areas in which exotic plants were growing, percent cover of exotics was not a significant component of sample sites, and exotic species richness was low at all sampling locations at 1.42 species per m². Data were analyzed using ordination and multiple regression to determine variables most responsible in explaining variation in exotic plant communities. Statistically significant site variables correlated with percent cover of exotics included percent cover of vascular native plants, percent cover litter, and percent bare soil at most study sites. The importance of these variables indicates that the presence of exotic plants in Wrangell-St. Elias is closely linked to disturbance, and that the invasion of exotic plants is in the initial phases.