Exotic Plant Invasion Risk in the Western United States

This model was constructed to model the risk of invasion by exotic plant species. Roads may directly influence exotic plant dispersal via disturbance during road construction or via alterations in soil regimes. For example, in Californian serpentine soil ecosystems, exotic plant species can be found up to 1km from the nearest road and Russian thistle (Salsola kali), an exotic forb growing along roads, is wind-dispersed over distances greater than 4km. Roads may also indirectly facilitate the dispersal of exotic grasses, such as crested wheatgrass (Agropyron cristatum), via human seeding along road verges or in burned areas near roads as a management strategy to curb the establishment of less desirable exotic grass species. The inputs [...]