The Uncertain Future of Tropical Forest Species1

IT IS WIDELY ANTICIPATED THAT HABITAT LOSS will cause a mass extinction of tropical forest species. To evaluate this possibility, Wright & Muller-Landau (2006, henceforth WML) project future net tropical forest loss from United Nations projections of human population growth and present day relationships between human population density and the percentage of original forest cover remaining for 45 countries that support 89.6 percent of extant, humid tropical forest. Absolute rates of deforestation (area/yr) are predicted to decline in this analysis, and urbanization is predicted to accelerate the decline to the extent that rural populations control forest cover change. These projections suggest that large areas of tropical forest cover will remain in 2030 and beyond, and thus that habitat loss will threaten extinction for a smaller proportion of tropical forest species than previously predicted. Brook et al. (2006, henceforth BBKS) object. BBKS repeat caveats presented by WML and raise additional objections. Here, we show why we believe most of these new objections are unfounded.