Continental and Insular Speciation in Pacific Land Birds

Abstract

Diamond, J. M. (Physiology Department, University of California Medical Center, Los Angeles, California 90024) 1977. Continental and insular speciation in Pacific land birds. Syst. Zool. 26:263-268. —Three modes of allopatric speciation can be distinguished, depending on whether the isolating geographic barrier is within a single land mass (“continental speciation”), between islands of the same archipelago, or between different archipelagoes (“insular speciation”). The contributions of these three modes to speciation in Pacific land birds are analyzed. Continental speciation in birds has occurred in no Pacific land mass smaller than Australia, New Guinea, and possibly New Zealand; intraarchipelagal speciation has occurred only on six of the most remote archipelagoes; and inter-archipelagal speciation has produced most of the sympatric bird species pairs from the Bismarcks to Samoa. The frequency of each mode depends on area and isolation of the island, and on mobility and perhaps population density of the taxa involved. What is an “island” to some taxa may be a “continent” to others. For example, New Caledonia behaves as a continent to higher plants, insects, and lizards, but not to birds or ferns. [Speciation; Pacific land birds.]