COS 41-2
Linking the geometry of habitat destruction to the magnitude of species extinctions and to loss of evolutionary and functional uniqueness
Current ecological changes and habitat loss due to human activities are assumed to be accompanied by significant loss of biodiversity. However, estimating the extent of the diversity loss is difficult, especially for understudied taxa. We ask: (1) How does spatial configuration of habitat destruction affect estimates of the loss of species richness? (2) What is the magnitude of the decline of evolutionary and functional uniqueness, relative to the loss of species richness? (3) Can the magnitudes of the loss of different aspects of biodiversity be linked to the spatial arrangement of species' ranges and to the topology of phylogenetic and functional trees? We address these questions using several continental-scale regions, three major taxa, and their phylogenetic supertrees and functional dendrograms. We use a strictly nested quadrat sampling (i.e. destruction) algorithm to estimate the magnitudes of the loss of different aspects of biodiversity under two distinct geometries of habitat destruction.
Results/Conclusions
We show that the rate of the loss of species richness and the associated rate of loss of evolutionary and functional uniqueness crucially depend on the geometry of habitat destruction. Across the three taxa on four continents, the extinction rate is higher when habitats are destroyed inward from the edge of a region than when habitats are destroyed outward from within. Phylogenetic and functional diversity are initially lost at a lower rate than species richness. These discrepancies depend predictably on spatial configuration of species ranges, and on the topology of the phylogenetic trees or functional dendrograms. Our findings suggest that growing data on phylogenies and functional traits, together with basic information on the structure of species' ranges may improve extinction estimates.