ECOLOGY/EVOLUTION

Long-Distance Violets

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Science  15 Dec 2000:
Vol. 290, Issue 5499, pp. 2035
DOI: 10.1126/science.290.5499.2035a

The Hawaiian archipelago continues to produce surprises for evolutionary biologists. Because all of the islands of the archipelago originated de novo from a volcanic hotspot in the central Pacific, the entire biota must trace its ancestry to propagules that traversed enormous distances by dispersal from other islands and from the continental Pacific Rim. For extant plants alone, nearly 300 successful colonizing events are estimated to have occurred.

Most of the biogeographic affinities of the islands are with other tropical regions, but Ballard and Sytsma now reveal an unsuspected connection to the Arctic. A molecular phylogenetic analysis of the relationships of Hawaiian woody violets links them to other Alaskan and Siberian violet species—rather than to South American ones as previously assumed. A large number of Alaskan bird species winter in Hawaii, suggesting a probable means of dispersal; experiments with violet seeds indicate that transport and survival in birds' crops is a viable mechanism. Molecular analyses may reveal more instances of unexpected biological relationships between tropical islands and the Arctic. — AMS

Evolution54, 1521 (2000).

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