REGIONAL- AND LOCAL-SCALE VARIATIONS IN PLANT DISTRIBUTION IN THE SONORAN DESERT

摘要

This study documents dominant woody species cover at 30 locales throughout the northern Sonoran Desert in order to observe distributional patterns and associations among taxa at the regional scale. Factor analysis revealed two main findings: first, although common taxa are broadly distributed over the same areas in the northern Sonoran Desert, species associations can be statistically distinguished locally; second, after factor analysis, Carnegiea gigantea density loaded highly (0.934) on the same factor with two of its common nurse species, Ambrosia deltoidea (0.843) and Olneya tesota (0.836), but not with Cercidium microphyllum (0.139), also a common nurse. This suggests that available cover alone does not explain the observed Carnegiea gigantea patterns.