Differential human impact on the survival of genetically distinct avian lineages

Abstract

SummaryAt the present time the earth is facing an anthropogenic (human-caused) mass extinction event that may eventually rival previous mass extinction events caused by drastic changes i n the physical environment; however, the impact of this event on the earth's biotic diversity remains difficult to predict. Patterns of extinction and endangerment in birds, one of the best known taxonomically among major groups of organisms, showed that the distribution of human impact has been non-uniform relative to phylogenetic relationships. Fifteen major avian lineages differed over 35-fold with respect to the frequency of historical extinction and over threefold with respect to frequency of current threat; and overall rates of both extinction and threat were significantly higher in non-passerine orders than in passerines. Moreover, among both passerines and non-passerines, the rate of historic extinction has been significantly higher for species in monotypic genera than for other species; and in passerines, the rate of current threat is significantly higher for species in monotypic genera than for other species. Thus, the anthropogenic extinction and threat to avian species has specifically targeted species that are phylogenetically and thus, presumably genetically, unique.