Estimations of the number, and preferably identity, of species that will be threatened by land-use change and habitat loss are an invaluable tool for setting conservation priorities.  I used collections data and ecoregions maps to generate spatially explicit distributions for over 40,000 vascular plant species from the Amazon basin (representing over 80% of the estimated Amazonian plant diversity). Using the distribution maps I then estimated the rates of habitat loss and associated extinction probabilities due to future land-use changes as predicted under two disturbance scenarios.  

Results/Conclusions

I predict that by 2050 land-use practices will reduce the habitat available to Amazonian plant species by approximately 12 to 24% resulting in 5 to 9% of species becoming “committed to extinction”, significantly fewer than previous estimates.  Contrary to other studies, I find that the primary determinant of habitat loss and extinction risk is not the area of species’ range but rather range location.  The resultant extinction risk estimates are a valuable conservation tool since they estimate not only the total percentage of Amazonian plant species threatened with extinction, but also the degree to which individual species and habitats will be affected by ongoing and future land use changes.