Land managers need better techniques to assess exotic plant invasions. We used the cross-correlation statistic, IYZ, to test for the presence of spatial cross-correlation between pair- wise combinations of soil characteristics, topographic variables, plant species richness, and cover of vascular plants in a 754 ha study site in Rocky Mountain National Park, Colorado, U.S.A. Us- ing 25 large plots (1000 m2) in five vegetation types, 8 of 12 variables showed significant spatial cross-correlation with at least one other variable, while 6 of 12 variables showed significant spatial auto-correlation. Elevation and slope showed significant spatial cross-correlation with all variables except percent cover of native and exotic species. Percent [...]
