Pacific Science, Volume 62, Number 3, 2008
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ItemA Framework for Assessing Impacts of Marine Protected Areas in Moorea (French Polynesia).(Honolulu, University of Hawaii Press, 2008-07)Marine Protected Areas (MPAs) have been promoted as effective management tools to protect biodiversity at local and global scales, but there remains considerable scientific uncertainty about effects of MPAs on species abundances and biodiversity. Commonly used assessment designs typically fail to provide irrefutable evidence of positive effects. In contrast, Before-After- Control-Impact (BACI) designs potentially remedy many of these problems by explicitly dealing with both spatial and temporal variation. Here, we document the historical context of implementation and the scientific assessment of MPAs recently established at eight sites around the island of Moorea, French Polynesia. In 2004, we designed and implemented a monitoring plan that uses a BACIPaired Series (BACIPS) design to quantify the effect of the MPAs. Twice per year, we monitor fish, corals, and other benthic invertebrates at 13 sites (eight within MPAs and five outside MPAs) around Moorea, in three distinct reef habitats (fringing, barrier reef, and outer slope). We present statistical analyses of data collected during five surveys ( July 2004 to July 2006), before the initiation of enforcement. We also assessed the potential of our program to detect future responses to the established MPA network. Our estimates of biomass for five categories of fishes (Acanthuridae, Chaetodontidae, Serranidae, Scaridae, and fisheries target species) within MPA sites generally track estimates in paired Control sites through time. Estimated statistical power to detect MPA effects (a 192% biomass increase within the MPA) was high at the MPA network scale but varied among taxonomic categories and reef habitats: power was high on the reef outer slope and lower in the lagoon, and generally high for acanthurids and chaetodontids. It did not vary significantly between sites. We discuss limitations of our approach (shared by all MPA assessments to date) and describe solutions and unique opportunities to redress these limitations in French Polynesia.
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ItemDietary Habits of the Introduced Cane Toad Bufo marinus (Amphibia: Bufonidae) on Ishigakijima, Southern Ryukyus, Japan.(Honolulu, University of Hawaii Press, 2008-07)We examined dietary habits of the introduced cane toad Bufo marinus at three sites representing different types of habitats (pond, forest, and rice paddy) on Ishigakijima Island, southern Ryukyus, Japan. Stomach contents analysis revealed that the toad mostly utilizes terrestrial arthropods, of which hymenopterans (mostly ants), adult coleopterans, hemipterans, and araneans dominated in the frequency of occurrence, hymenopterans in the numerical proportion, and larval lepidopterans, adult coleopterans, and larval dipterans in the volumetric proportion. Comparisons in taxonomic composition of the toad’s stomach contents and pitfall and sweeping net samples suggested ignorance or avoidance of Amphipoda by the toad. Our results suggest the possibility of considerable predation pressure of B. marinus upon the native arthropods, and ants in particular, on Ishigakijima Island.
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ItemDegree and Pattern of Gene Flow in Several Scleractinian Corals in the Ryukyu Archipelago, Southern Japan.(Honolulu, University of Hawaii Press, 2008-07)Dispersal distance of planktonic larvae of coral reef organisms is influenced by their ecological characteristics and environmental factors such as current flow and physical structure of reefs. This study reviews the degree and pattern of genetic differentiation in scleractinian corals in the Ryukyu Archipelago, compared with other regions. Small-scale genetic heterogeneity, but broadscale homogeneity, was detected in some species, including brooders and spawners in the Ryukyus. Comparison with other regions indicated that limited gene flow on a small spatial scale (i.e., self-recruitment) seemed to occur in many regions. However, the degree of gene flow over larger distances was complex and species-dependent. With an implication for conservation in the Ryukyus, the larval source hypothesis, which states that coral larvae were recruited from the Kerama Islands to the Okinawa Islands, was consistent with results illustrating high gene flow in some species. Thus, conservation of corals in the Kerama Islands is high priority. Detection of genetic breaks between the southern and central Ryukyus was not common among species. The genetic structure observed in corals is highly variable and depends on both species and spatial scale in the Ryukyus. In addition, the complex genetic structures of corals may be related to coral-specific destructive events, such as bleaching, outbreaks of crown-of-thorns starfish, and disease. Further studies will provide new insights and a more detailed view of the genetic structure of corals by using different markers (e.g., microsatellites) and approaches (assignment tests and clustering analysis), which will provide useful information for coral reef conservation.
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ItemLow Genetic Diversity of Oval Squid, Sepioteuthis cf. lessoniana (Cephalopoda: Loliginidae), in Japanese Waters Inferred from a Mitochondrial DNA Non-coding Region.(Honolulu, University of Hawaii Press, 2008-07)Genetic diversity and population structure of Japanese populations of the oval squid, Sepioteuthis cf. lessoniana, were compared with populations from Taiwan and Vietnam using nucleotide sequences of the mitochondrial DNA non-coding region 2. In total, 402 nucleotide sequences representing 242 individuals from Japanese waters (Ishikawa, Japan Sea coast of Honshu; Tokushima, eastern Shikoku; Nagasaki, western Kyushu; and Okinawajima and Ishigakijima Island, in the Ryukyu Archipelago) and the East and South China Seas (Keelung, northern Taiwan; Vietnam, Gulf of Tonkin) were examined. Among the 29 haplotypes recognized, haplotype no. 1 was shared by more than 75% of individuals from Japanese localities, whereas it was found in less than 13% of specimens from the East and South China Seas populations. Conversely, the East and South China Seas populations included more than 30% individuals with haplotype no. 2, whereas less than 10% of haplotype no. 2 individuals were from Japanese localities. The differences of haplotype and nucleotide diversities between pooled Japanese populations (0.2639, 0.23%) and the East and South China Seas populations (0.7900, 1.01%) indicate that S. cf. lessoniana from Japanese waters exhibits lower genetic diversity. An analysis of molecular variance between the Japanese populations and the East and South China Seas populations was highly significant. A minimum spanning tree of 29 haplotypes and an Unweighted Pair Group Method with Arithmetic mean (UPGMA) tree based on pairwise FST comparisons also supported the separation between Japanese and the East and South China Seas populations. We suggest that the Kuroshio Current physically limits gene flow and has thus caused the differences in genetic diversity among the populations examined.
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ItemSystematic Review of Late Pleistocene Turtles (Reptilia: Chelonii) from the Ryukyu Archipelago, Japan, with Special Reference to Paleogeographical Implications.(Honolulu, University of Hawaii Press, 2008-07)The Quaternary terrestrial turtle fauna of the Ryukyu Archipelago was reviewed on the basis of recently excavated fossils, as well as literature information. As a result, five extinct species (four geoemydids [Cuora sp., Geoemyda amamiensis, Mauremys sp., and another species with undetermined generic and specific status] and one testudinid [Manouria oyamai]) were recognized from Late Pleistocene cave and fissure deposits. Two of the three turtles currently occurring in this archipelago (C. flavomarginata and G. japonica) were also recognized from comparable deposits on islands, including those where they do not occur at present. These records indicate that the terrestrial turtles of the Ryukyus were much more diverse during the Late Pleistocene than at present, and that extinction has occurred during the last few tens of thousands of years not only for those five fossil species but also for some island populations of the extant species. Distributions of three of the extinct species (G. amamiensis, Cuora sp., and the geoemydid [genus and species undetermined]), confined to the central Ryukyus, are concordant with the currently prevailing hypothesis of Ryukyu paleogeography, which assumes a relatively long isolation of this region and much more recent insularization of the southern Ryukyus. In contrast, distributions of the remaining two extinct species (Man. oyamai and Mau. sp.) must be explained by some ad hoc scenario or, otherwise, drastic modification of the current hypothesis.
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ItemGenetic Relationships among Species of Meretrix (Mollusca: Veneridae) in the Western Pacific Ocean.(Honolulu, University of Hawaii Press, 2008-07)We compared allozymes at 12 loci in 12 populations of six species of Meretrix: M. lusoria ( Japan, Korea, and Taiwan), M. petechialis (China and Korea), M. ovum (Thailand and Mozambique), M. lyrata (China), M. lamarckii ( Japan), and Meretrix sp. A (Okinawa, Japan). Our allozyme results were generally consistent with the major groupings currently recognized within the genus based on morphological characters. However, we found two cryptic or undescribed species: Meretrix sp. A from Okinawa and M. cf. lusoria from Taiwan. The shell characters of Meretrix sp. A were similar to those of M. lamarckii, but the species was genetically distinct (Nei’s genetic distance D > 0.845) from all other species examined. The Taiwanese Meretrix population was morphologically indistinguishable from Japanese M. lusoria, although the genetic distance between the Taiwanese and Japanese populations showed a high degree of genetic differentiation (D > 0.386). Meretrix lusoria seedlings were introduced into Taiwan from Japan in the 1920s, and Japanese M. lusoria was previously thought to be established as a cultured stock. However, our results suggest that the Taiwanese population may represent a sibling or cryptic species of M. lusoria.
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ItemBiogeography of the Decapod and Stomatopod Crustacea of the Tropical Pacific: Issues and Prospects.(Honolulu, University of Hawaii Press, 2008-07)Biogeographic patterns of the Crustacea (Decapoda and Stomatopoda) are given for the tropical Pacific, based on recent taxonomic studies combined with emergence of regional databases. Conclusive results are still difficult to obtain due to incomplete regional inventories and existence of complexes of sibling species with unclear taxonomic status. A time-series graph of the number of new records plotted against time is computed for several central Pacific islands (French Polynesia, Pitcairn, Easter Island, and Clipperton). It demonstrates that the fauna is still insufficiently known in those places. A biodiversity gradient is calculated for several taxa between West and East Pacific. The traditional decrease between Australia and French Polynesia is confirmed for higher taxa (Brachyura, Anomura), but at lower taxonomic levels it is not always verified (e.g., hermit crabs, Calcinus; crabs, Trapezia). A map is presented illustrating the following provisional biogeographic results: (1) cryptic endemic species recognized in the Marquesas Islands; (2) presence of a distinct faunistic province in the South Pacific, along the 25_ S parallel, including Rapa and Easter Islands; (3) theoretical position of the border between the Indo-West Pacific (IWP) and East Pacific (EP) faunistic provinces (84_ W on the seamounts of Sala y Go´mez/Nazca and 110_ W on Clipperton); (4) differences between Clipperton, with a mixed IWP-EP fauna (43% IWP versus 57% EP species), and the Gala´- pagos, with obvious EP affinities (10% IWP versus 90% EP species).
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ItemCanopy Multilayering and Woody Species Diversity of a Subtropical Evergreen Broadleaf Forest, Okinawa Island.(Honolulu, University of Hawaii Press, 2008-07)Woody species diversity and the spatial distribution of trees in a subtropical evergreen broadleaf forest on a silicate substrate, Okinawa Island, were investigated to determine the forest’s architectural stratification. The forest stand consisted of four architectural layers. The values of Shannon’s index H0 and Pielou’s index J 0 tended to increase from the top layer downward, except for the bottom layer. The lower layers contained many species relative to their smaller height ranges. High woody species diversity of the forest depended on small trees. This trend of species diversity was different from that of forest on a limestone substrate on Okinawa Island, where high woody species diversity depended on large trees. Conservation of small trees in the lower layers, especially the bottom layer, is indispensable to maintain diversity in Okinawan evergreen broadleaf forests. Castanopsis sieboldii (Mak.) Hatusima had the highest importance value in all layers, indicating that it is typically a facultative shade species as well as a climax species. The spatial distribution patterns of trees were found to be random in the lower three layers, but in the top layer clumping seemed to occur at three spatial scales. A high degree of overlapping in spatial distributions of trees among the layers suggested that light cannot penetrate easily into the lower layers. As a result, most species in the lower layers must be shade-tolerant. Mean weight index decreased from the top toward the bottom layer, and tree density increased from the top downward. This trend resembled the mean weight-density trajectory of self-thinning plant populations.
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ItemMolecular Phylogeography of the Endemic Five-lined Skink (Plestiodon marginatus) (Reptilia: Scincidae) of the Ryukyu Archipelago, Japan, with Special Reference to the Relationship of a Northern Tokara Population.(Honolulu, University of Hawaii Press, 2008-07)Phylogenetic relationships were inferred for populations of the Ryukyu five-lined skink Plestiodon marginatus, a species showing an extraordinary distribution across the Tokara Tectonic Strait. Phylogenetic analyses of 809 base positions of the mitochondrial 12S and 16S rRNA genes supported collective divergence of the southern Tokara and northern Amami populations, which have been classified as P. m. oshimensis. A population from Nakanoshima, an island of the Tokara Group north of the Tokara Tectonic Strait, has the closest affinity with the Okinawajima population of P. m. marginatus rather than with the geographically closer southern Tokara and northern Amami populations. This result is concordant with that of a recent allozyme study and suggests an origin of the Nakanoshima population through long-distance dispersal from the Okinawa Island Group. Also, our results strongly suggest a closer relationship of a population of P. m. oshimensis from Okinoerabujima, a southern island of the Amami Group, with P. m. marginatus from Okinawajima than with the ‘‘consubspecific’’ southern Tokara and northern Amami populations. Both Nakanoshima and Okinoerabujima populations are usually referred to as P. m. oshimensis, and therefore our results indicate nonmonophyly of P. m. oshimensis in the current taxonomic arrangement.
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ItemFlicker Light Effects on Photosynthesis of Symbiotic Algae in the Reef- Building Coral Acropora digitifera (Cnidaria: Anthozoa: Scleractinia).(Honolulu, University of Hawaii Press, 2008-07)Reef-building corals inhabit a variety of aquatic habitats with a range of light conditions. Because the coral host depends on photosynthetic products assimilated from endosymbiotic algae, reef-building corals have to cope with irradiance fluctuations on instantaneous to seasonal time scales. Underwater highfrequency light fluctuations resulting from the lens effect on the water surface are prominent in oligotrophic coral reef environments, a phenomenon known as flicker light. Effects of flicker light on endosymbiont photosynthesis of the reef-building coral Acropora digitifera (Dana, 1846) were evaluated with pulse amplitude modulation chlorophyll fluorometry. At supersaturating light intensities, photosynthesis was less inhibited by flicker light than by constant light. Reduction in photoinhibition by flicker light was pronounced at high water temperatures. Flicker light may strongly influence endosymbiont photosynthesis of corals inhabiting shallow reef habitats, especially during periods of strong solar irradiance and high water temperature.