Riders in the sky (islands): using a mega-phylogenetic approach to understand plant species distribution and coexistence at the altitudinal limits of angiosperm plant life.

Although we found evidence for strong phylogenetic clustering within alpine summits, we were not able to reject models of species-neutral processes to explain patterns of floristic diversity. Our results suggest that plant community structure in high-alpine regions can also be shaped by neutral processes, and not through the sole action of environmental selection as traditionally assumed for harsh and stressful environments.