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Aim: Oceanic hotspot archipelagos are important systems for studying evolutionary and ecological processes; however, studies of macrofungi in these habitats are extremely limited. We assessed diversity across habitat types, using DNA point data to draw inferences about biogeographical signal, endemicity and potential radiation for fungi of a representative isolated island (Moorea, French Polynesia) within the poorly known South Pacific bioregion, comparing resulting patterns to those previously inferred for more comprehensively sampled plants and animals. Location: Moorea and Tahiti, French Polynesia. Taxon: Fungi (Basidiomycota, Ascomycota). Methods: Morphological characters and similarity assessment of rDNA‐ITS sequence data were used to measure diversity and habitat associations. A Monte Carlo simulation method was developed to detect biogeographical signal and assess its significance. Results: A total of 553 specimens yielded 205 morphospecies; 433 sequenced specimens yielded a molecular:morphological richness ratio of 1.24:1. Approximately 58% of sequences lacked a close (≥98%) GenBank match. Community composition differed by vegetation type, with highest similarity between forest types occupying similar low‐elevation habitats. A predominant Australian/Oceanean biogeographical signal was detected. Main conclusions: Moorea fungi exhibit a strong Australian biogeographical affinity as reported for other taxa, supplemented by more recent introductions. Like Society Islands plants and animals, macrofungi may have high endemism. Morphological evidence does not indicate that intra‐island radiation has occurred, though molecular evidence suggests possible cryptic speciation. Habitat types differ in their biogeographical affinities, but habitat does not appear to be driving radiation. This study introduces a robust method for inferring biogeographical signal using sequence database comparisons, applicable to other taxa and systems for which only point data are available. [ABSTRACT FROM AUTHOR]

I examined the relative influence of eight spatial characteristics on native plant diversity in 22 volcanic high islands of eastern Polynesia. The characteristics used as potential predictors in this study included island area, highest elevation, distance to the nearest continent, distance to the nearest archipelago, distance to the nearest similar island, index of isolation, distance to the largest and highest island of Tahiti, and distance to the "cyclonic alley." Among characteristics studied, native plant diversity (indigenous and endemic species) was primarily linked with the island area and highest elevation of the islands. Contemporary cyclones were an important predictor of indigenous plant diversity in the remote islands surveyed. In the study area, this result suggests that cyclones, moving from the west Pacific Ocean basin to the eastern Polynesian islands, have provided more indigenous species to the remote high islands located close to the cyclonic alley. Isolation did not appear as a significant predictor of native plant diversity in the high islands surveyed, possibly due to a stepping-stone-island effect and the proximity of the cyclonic alley. These findings suggest that isolation could be tempered by a cyclonic-transport-flow effect in the study area, thus reducing the effective distance of the remote islands from the mainland source pool for seed dispersal. [ABSTRACT FROM AUTHOR]

With only a single extant representative, endemic to the Tuamotu Archipelago, the Polynesian sandpipers ( Aechmorhynchus and Prosobonia) may have had a larger distribution in Eastern Polynesia in the past, with four endemic taxa. Although these aberrant sandpipers' membership to the Scolocapidae has been well supported, finding their closest living taxa has proved difficult and the phylogenetic relationships of these taxa have remained unresolved. We present the first molecular analysis of the Polynesian sandpipers, including sampling of the only known specimen of the extinct Prosobonia leucoptera, collected in 1773. Based on mitochondrial and nuclear gene sequence data, the phylogenetic analyses demonstrate that the Polynesian sandpipers were sister taxa and belonged to the clade that included the other sandpipers ( Calidris and allies) and turnstones ( Arenaria), although without a close relative among extant genera. Divergence time estimates suggested that the lineage leading to Prosobonia diverged from the other extant sandpipers during the Oligocene and that either the Line Islands or the Tuamotu Archipelago were probably the first archipelagos colonized by the Prosobonia lineage. On the basis of these results, we suggest that Aechmorhynchus parvirostris and Prosobonia leucoptera be regarded as related species within the same genus, and thus that the senior name Prosobonia be used for both taxa. [ABSTRACT FROM AUTHOR]

In the Society archipelago (French Polynesia), Acrocephalus reed warblers are known only from four islands: Tahiti, Mo’orea, Huahine and Raiatea. All populations are now extinct except on Tahiti. Our knowledge of these birds is based on a small number of specimens preserved in museums, collected mostly during the 19th century. We present here a review of the past and present distribution, habitat and threats to the Society Islands reed warblers, including details on the specimens in museum collections. We compare the external morphology of the different populations, and use samples from museum specimens to propose a molecular phylogeny of all taxa based on partial cytochrome b gene sequences. The genetic data do not support the monophyly of the Society Islands reed warblers, which probably derived from three different lineages, found in Tahiti, Mo’orea and in the cluster Raiatea–Huahine. We outline the taxonomic consequences of this phylogeny. Our results support the hypothesis that evolutionary pattern, not distance between islands, shaped the long-distance colonization of oceanic islands by reed warblers. [ABSTRACT FROM AUTHOR]

Geographic isolation is widely viewed as a key component of insular radiations on islands. However, strong ecological affinities may also reinforce isolation and promote genetic divergence. The black fly fauna in the Society Islands French Polynesia is notable for the number of closely related endemic species (31), and the morphological and habitat diversity of the larvae. Here, we measure ecological and morphological differences within and between two closely related species, Simulium oviceps and Simulium dussertorum and relate these differences to genetic distance. Phylogenetic analyses of a 920 bp fragment of the cytochrome oxidase I (COI) gene revealed a well-supported, ecologically divergent S. oviceps clade (larvae found in rivers instead of cascades) that shows little morphological differentiation. For both S. oviceps and S. dussertorum, genetic distance among populations is related to larval habitat, with cascade populations showing greater isolation from each other than river populations. Our data support the hypothesis that larval ecological shifts have played a role in the radiation of this black fly fauna.Heredity (2007) 99, 452–459; doi:10.1038/sj.hdy.6801023; published online 4 July 2007 [ABSTRACT FROM AUTHOR]

Aim Phylogenetic studies concerning island biogeography have been concentrated in a fraction of the numerous hot-spot archipelagos contained within the Pacific Ocean. In this study we investigate relationships among island populations of the thomisid spider Misumenops rapaensis Berland, 1934 across the Austral Islands, a remote and rarely examined southern Pacific hot-spot archipelago. We also assess the phylogenetic position of M. rapaensis in relation to thomisids distributed across multiple Polynesian archipelagos in order to evaluate the proposed hypothesis that thomisid spiders colonized Polynesia from multiple and opposing directions. The data allow an examination of genetic divergence and species accumulation in closely related lineages distributed across four Polynesian archipelagos. Location The study focused on four Polynesian hot-spot archipelagos: the Austral, Hawaiian, Marquesan and Society islands. Methods Mitochondrial DNA sequences comprising c. 1400 bp (portions of cytochrome oxidase subunit I, ribosomal 16S and NADH dehydrogenase subunit I) were obtained from thomisid spiders (64 specimens, representing 33 species) collected in the Australs, the Hawaiian Islands, the Society Islands, the Marquesas, Tonga, Fiji, New Zealand, New Caledonia and North and South America. Phylogenetic analyses using parsimony, maximum-likelihood and Bayesian approaches were employed to resolve relationships of M. rapaensis to other Polynesian Misumenops and across the Austral Islands. Results Rather than grouping with other Misumenops spp. from the archipelagos of the Society Islands, Marquesas and Hawaiian Islands, M. rapaensis appears more closely related to Diaea spp. from Tonga, Fiji, New Zealand and New Caledonia. Phylogenetic analyses strongly support M. rapaensis as monophyletic across the Austral Islands. Misumenops rapaensis sampled from the two older islands (Rurutu and Tubuai) form reciprocally monophyletic groups, while individuals from the younger islands (Raivavae and Rapa) are paraphyletic. Across the Austral Islands, M. rapaensis exhibits a surprising level of genetic divergence (maximally 11.3%), an amount nearly equivalent to that found across the 16 examined Hawaiian species (14.0%). Main conclusions Although described as a single morphologically recognized species, our results suggest that M. rapaensis comprises multiple genetically distinct lineages restricted to different Austral Islands. Phylogenetic relationships among the island populations are consistent with sequential colonization of this lineage down the Austral archipelago toward younger islands. Analyses support the hypothesis that thomisid spiders colonized the central Pacific multiple times and suggest that M. rapaensis arrived in the Austral Islands from a westward direction, while Misumenops found in neighbouring archipelagos appear to be more closely related to New World congeners to the east. Finally, our data detect asymmetrical rates of morphological evolution and species diversification following colonization of four different Polynesian archipelagos. [ABSTRACT FROM AUTHOR]