Fig. 2. Spatial autocorrelation observed for spatial patterns of butterfly species richness using each of the three grid systems developed for this study (blue circles, 5° quadrat system; red squares, unequal-area quadrat system; green diamonds, 2° quadrat system). Spatial autocorrelation, measured as Moran's I, declines with increasing distance between study quadrats regardless of quadrat size, contrary to unusual observations from a single study of Wyoming vertebrates (Fraser 1998). That distance varies with the resolution of the grids, which ranges from 2° to 5°.