The spatial structure of beta-diversity revealed with imaging spectroscopy

David A. Coomes, Department of Plant Sciences, University of Cambridge, Cambridge, United Kingdom

Background/Question/Methods Both niche and stochastic dispersal processes structure the extraordinary diversity of tropical plants, but determining their relative contributions has proven challenging. We address this question using airborne imaging spectroscopy to estimate canopy beta-diversity for an extensive region of a Bornean rainforest and challenge these data with models incorporating niches and dispersal.
Results/Conclusions We show that remotely sensed and field-derived estimates of pairwise dissimilarity in community composition are closely matched, proving the applicability of imaging spectroscopy to provide beta-diversity data for entire landscapes of over 1000 ha containing contrasting forest types. Our model reproduces the empirical data well and shows that the ecological processes maintaining tropical forest diversity are scale dependent. Patterns of beta-diversity are shaped by stochastic dispersal processes acting locally whilst environmental processes act over a wider range of scales.