Islands Generate Bird Biodiversity

Article excerpt

Island life sounds quite appealing in winter months as many of us migrate to warmer and lusher locales. Islands and their flora and fauna also hold a special fascination for scientists and naturalists, as they've discovered islands' rich biodiversity and the large proportion of species found on single islands and nowhere else on Earth.

Now, two American Museum of Natural History biologists have overturned conventional thinking that islands are evolutionary "dead-ends" with a study demonstrating that biodiversity flows "upstream"-from islands to continents, as well as "downstream"-from continents to islands-by showing that birds from widely dispersed South Pacific islands have contributed to continental bird biodiversity in Australia.

This new study of a diverse and brilliantly colored bird family-the monarch flycatchers, found throughout Australasia and the tropical Pacific-by Christopher E. Filardi, biodiversity scientist in the Museum's Center for Biodiversity and Conservation and Department of Ornithology, and Robert G. Moyle, research scientist in the Museum's Department of Ornithology and Ambrose Monell Molecular Laboratory, was published in the November 10, 2005, issue of the journal Nature.

Drs. Filardi and Moyle arrived at new estimates of the evolutionary relationships among these birds based on the genetic relatedness among species in an attempt to understand the processes behind the pattern of the birds' geographical distribution. Their analysis shows that a large and diverse array of monarch flycatchers resulted from a single radiation involving nearly every major Pacific archipelago, and that some species with ancestors originating on Pacific islands took hold in Australia and New Guinea at some time in the past. …