Data from: Assembling a species–area curve through colonization, speciation and human-mediated introduction

Aim: The fundamental biogeographical processes of colonization, speciation
and extinction shape island biotas in space–time. On oceanic islands, area
and isolation affect these processes and resulting biodiversity patterns.
In the Anthropocene, a new human-mediated colonization dynamic is altering
insular ecosystems world-wide. Here, we test predictions about the roles
of archipelago area and isolation in structuring ant diversity patterns
through effects on both natural and anthropogenic biogeographical
processes. Location: Tropical Pacific islands. Methods: We compiled a
comprehensive data set of ant faunal compositions across tropical Pacific
archipelagos. Using regression analysis we evaluated the bivariate and
interactive effects of area and isolation on the number of colonizing
lineages, native species, endemic species, exotic species and total
richness in the archipelago. Results: There is a strong species–area
effect and a much more modest isolation effect on total ant species
richness across the Pacific archipelagos. The number of colonizing
lineages of each archipelago is strongly driven by the isolation of the
archipelago. Endemic species are present in large archipelagos of low and
intermediate isolation. The most remote archipelagos are nearly devoid of
endemic lineages and their ant faunas are largely composed of Pacific
Tramp species and exotics brought from outside the Pacific region. Main
conclusions: The prominent species–area curve in Pacific ants emerged over
time through multiple processes. The colonization of lineages is
determined primarily by isolation, with few or no lineages reaching remote
archipelagos. Cladogenesis mediates the isolation effect and increases the
area effect through the differential radiation of lineages in large
archipelagos. In the Anthropocene, the assembly of the species–area
relationship has accelerated dramatically through human-mediated
colonization. Overall, our results support a view that species–area curves
reflect regulating limits on species richness that scale with area, but
that multiple biogeographical processes can occur to achieve these limits.