Summary: Island area and species diversity in the southwest Pacific Ocean:
is the lizard fauna of Vanuatu depauperate?
Alison M. Hamilton, Joseph H. Hartman and Christopher C. Austin
A. M. Hamilton (email@example.com) and C. C. Austin, Dept of Biological Sciences and Museum of Natural Science, Louisiana State Univ.,
119 Foster Hall, Baton Rouge, LA 70803, USA. ┴ J. H. Hartman, Dept of Geology and Geological Engineering, Univ. of North Dakota, Grand
Forks, ND 58202, USA.
One island group suggested to be an exception to the species┴area relationship is the Vanuatu Archipelago, a group of
13 large and 80 small islands in the southwest Pacific Ocean. To test the hypothesis that the lizard fauna of the Vanuatu
Archipelago does not meet the predictions of the species┴area relationship, and thus is depauperate, we compare diversity
among several island groups in the southwest Pacific: Fiji, the Loyalty Islands, New Caledonia, Samoa, the Solomon
Islands, Tonga, and Vanuatu. We found that the lizard diversity of Vanuatu meets the pattern of diversity predicted by
the species┴area relationship. The Solomon Islands, the largest and least isolated oceanic archipelago considered, has the
greatest species diversity and endemism of the oceanic islands. Inclusion or exclusion of island groups based on factors
such as geologic history or faunal source affects the strength of the relationship between diversity, area, and history of
emergence, and influences perceptions of diversity within individual archipelagos. In addition to island size, factors such
evolutionary time scale, speciation, and archipelago complexity influence species richness on islands.
The relationship between species richness, island area, and
island isolation is one of the most fundamental models in
ecology and biogeography (Arrhenius 1921, Gleason 1922,
Preston 1962, MacArthur and Wilson 1963, 1967). In