Extinction of the blue antelope hippotragus leucophaeus: Modeling predicts non-viable global population size as the primary driver

Abstract

The extinction of the blue antelope Hippotragus leucophaeus in 1800 is poorly documented and understood, and has been ascribed to a combination of habitat loss and overhunting by early European colonists with firearms. We modeled the distribution and abundance of this species to gain insight into the extinction process. Model outputs indicate that prior to the arrival of European colonists, blue antelope were restricted to a small area (c. 4,300 km2), with an estimated population of only 370 individuals. We conclude that the historical population of blue antelope was functionally an island population in terms of demographic and genetic processes, by virtue of its limited distribution, small size and lack of metapopulation processes. The small population (effective population size ~100 individuals) would have been vulnerable to stochastic effects and was probably trapped in an extinction vortex. Hunting pressure by European colonists merely provided the coup de grace to a species already on the brink of extinction. © Springer Science+Business Media B.V. 2009.