Speciation and Extinction Longterm Prospects

The earth is experiencing an anthropogenic mass extinction of species comparable in magnitude to the catastrophic mass extinctions of past geological times. As many authors have shown, these extinctions reflect combined impacts of several types of human activity, especially habitat destruction, exploitation of plant and animal populations, and introduc tion of alien species (Cox 1999). For most groups of organisms, extinctions have been concentrated in insular environments, including islands...

Extinction and Extirpation due to Predation and Herbivory

The role of alien species in extinction on islands has a long history. Numerous native birds on Pacific islands, including Hawaii, were driven to extinction by predation by dogs, pigs, and rats, together with human hunting, following the arrival of Polynesian colonists (Olson and James 1984 Steadman 1995). In Hawaii alone, about 60 species became extinct during the Polynesian period. These included flightless species of geese, ibis, and rails, as well as flying members of several other...