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New pteridophyte species and combinations from the Marquesas Islands, French Polynesia
David Lorence,Warren Wagner,Kenneth Wood,Alan Smith
PhytoKeys , 2011, DOI: 10.3897/phytokeys.4.1602
Abstract: Intensive botanical exploration of the Marquesas Islands (French Polynesia) for the Vascular Flora of the Marquesas Islands and Flore de la Polynésie fran aise projects has resulted in numerous additional new collections from these islands. Study of these collections has brought to light 11 new species of pteridophytes (ferns and lycophytes) which are described herein: Blechnum pacificum Lorence & A. R. Sm., sp. nov., Cyclosorus castaneus A. R. Sm. & Lorence, sp. nov., Cyclosorus florencei A. R. Sm. & Lorence, sp. nov., Dryopteris macropholis Lorence & W. L. Wagner, sp. nov., Dryopteris sweetorum Lorence & W. L. Wagner, sp. nov., Polystichum kenwoodii Lorence & W. L. Wagner, sp. nov., Polystichum uahukaense Lorence & W. L. Wagner, sp. nov., Pteris hivaoaensis Lorence & K. Wood, sp. nov., Pteris marquesensis Lorence & K. R. Wood, sp. nov., Pteris tahuataensis Lorence & K. R. Wood, sp. nov., and Thelypteris marquesensis Lorence & K. R. Wood, sp. nov. One new combination is made: Cyclosorus marquesicus (Holttum) Lorence & A. R. Sm., comb. nov. (based on Plesioneuron marquesicum Holttum). An analysis of the conservation status of these new Marquesas Islands taxa reveals they are in need of inclusion in the IUCN Red List with conservation status ranging from vulnerable (one species), and endangered (four species), to critically endangered (five species).
Population genetic structure of Aedes polynesiensis in the Society Islands of French Polynesia: implications for control using a Wolbachia-based autocidal strategy
Corey L Brelsfoard, Stephen L Dobson
Parasites & Vectors , 2012, DOI: 10.1186/1756-3305-5-80
Abstract: A panel of eight microsatellite loci were used to genotype A. polynesiensis samples collected in French Polynesia from 2005-2008 and introgressed A. polynesiensis and Aedes riversi laboratory strains. Examination of genetic differentiation was performed using F-statistics, STRUCTURE, and an AMOVA. BAYESASS was used to estimate direction and rates of mosquito movement.FST values, AMOVA, and STRUCTURE analyses suggest low levels of intra-island differentiation from multiple collection sites on Tahiti, Raiatea, and Maupiti. Significant pair-wise FST values translate to relatively minor levels of inter-island genetic differentiation between more isolated islands and little differentiation between islands with greater commercial traffic (i.e., Tahiti, Raiatea, and Moorea). STRUCTURE analyses also indicate two population groups across the Society Islands, and the genetic makeup of Wolbachia infected strains intended for release is similar to that of wild-type populations from its island of origin, and unlike that of A. riversi.The observed panmictic population on Tahiti, Raiatea, and Moorea is consistent with hypothesized gene flow occurring between islands that have relatively high levels of air and maritime traffic, compared to that of the more isolated Maupiti and Tahaa. Gene flow and potential mosquito movement is discussed in relation to trials of applied autocidal strategies.Aedes polynesiensis is a day biting pest and the major vector of Wuchereria bancrofti and a secondary vector of Dengue virus in the South Pacific [1]. A. polynesiensis established concurrent with the arrival of man in the South Pacific, approximately 1500-3000 years ago and has spread throughout French Polynesia and other island groups ranging from Fiji to the Tuamotu Archipelago [2]. A. polynesiensis is adapted to ovipositing in both man-made (e.g., rain water catch basins, discarded bottles, buckets, and cans) and natural containers [3,4]. Natural containers that A. polynesiensis oviposits in
Genetic Network and Breeding Patterns of a Sicklefin Lemon Shark (Negaprion acutidens) Population in the Society Islands, French Polynesia  [PDF]
Johann Mourier, Nicolas Buray, Jennifer K. Schultz, Eric Clua, Serge Planes
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0073899
Abstract: Human pressures have put many top predator populations at risk of extinction. Recent years have seen alarming declines in sharks worldwide, while their resilience remains poorly understood. Studying the ecology of small populations of marine predators is a priority to better understand their ability to withstand anthropogenic and environmental stressors. In the present study, we monitored a naturally small island population of 40 adult sicklefin lemon sharks in Moorea, French Polynesia over 5 years. We reconstructed the genetic relationships among individuals and determined the population’s mating system. The genetic network illustrates that all individuals, except one, are interconnected at least through one first order genetic relationship. While this species developed a clear inbreeding avoidance strategy involving dispersal and migration, the small population size, low number of breeders, and the fragmented environment characterizing these tropical islands, limits its complete effectiveness.
Best Management Strategies for Sustainable Giant Clam Fishery in French Polynesia Islands: Answers from a Spatial Modeling Approach  [PDF]
Simon Van Wynsberge, Serge Andréfou?t, Antoine Gilbert, Arsène Stein, Georges Remoissenet
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0064641
Abstract: The giant clam Tridacna maxima has been largely overexploited in many tropical regions over the past decades, and was therefore listed in appendix II of the Convention of International Trade in Endangered Species (CITES) in 1985. In French Polynesia, several atolls and islands harbor the world’s highest stocks of giant clams in very shallow and accessible areas, which are therefore highly vulnerable to fishing pressure. The local fishery authority (i.e., Direction des Resources Marines or “DRM”) implemented several management schemes in 2002 to control and regulate fishing pressure. However, for further decisions DRM was missing a sensitivity analysis on the effectiveness of the possible management actions. Here, we report on the use of a deterministic Viable Population Analysis (VPA) and spatially-explicit age-based population model that simulated the 30-year trajectory of a Tridacna maxima stock under different management approaches. Specifically, given various scenarios of intra-island larval dispersal, we tested which of No-take-Areas (NTAs), rotational closures, size limits, quotas, and restocking schemes would lead to the highest future stocks in Tubuai and Raivavae, two exploited islands of the Austral archipelago. For both islands, stock abundances were estimated in 2004/2010 and 2005/2010 respectively, and natural mortalities were assessed previously only in Tubuai. When compared to field data, the model successfully predicted the 2010 stocks for Tubuai, but proved to be less reliable for Raivavae, where natural mortality rates may well be different from those on Tubuai. For Tubuai, the spatial model suggested that reducing fishing effort (through fixed quotas) and banning fishing below the 12 cm size limit (as currently implemented) were the most effective management actions to sustain T. maxima populations into the future. Implementing NTAs was of poor effectiveness. NTAs increased giant clam stock inside the protected area, but also increased overfishing in the neighboring areas, and were ineffective overall.
Tsunami risk assessment in the Marquesas Islands (French Polynesia) through numerical modeling of generic far-field events  [PDF]
H. Hébert,F. Schindelé,P. Heinrich
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2001,
Abstract: Earthquakes occurring at the Pacific Rim can trigger tsunamis that propagate across the ocean and can produce significant damages far away from the source. In French Polynesia, the Marquesas Islands are the most exposed to the far-field tsunami hazards, since they are not protected by any outer coral reef and since submarine slopes are less steep than in other islands. Between 1994 and 1996, four tsunamis have reached the bays of the archipelago, among them, the tsunami initiated by the Chilean Mw 8.1 earthquake, produced up to 3 m high waves in Tahauku Bay. Numerical modeling of these recent events has already allowed us to validate our method of resolution of hydrodynamics laws through a finite-difference scheme that simulates the propagation of the tsunamis across the ocean and computes the inundation heights (run-up) in remote bays. We present in this paper the simulations carried out to study potentially threatening areas located at the Pacific Rim, on the seismogenic Aleutian and Tonga subduction zones. We use a constant seismic moment source (that of the Mw 8.1 Chile 1995 earthquake, M0 = 1.2 1021 N.m) located at several potential epicenters, with the fault strike adapted from the regional seismotectonics pattern. Our results show that the sources chosen in the Aleutian trench do not produce large inundations in the Marquesas bays, except for the easternmost source (longitude 194° E). Sources located in the Tonga trench do not produce high amplifications either, except for the northernmost one (latitude 16° S). We also discuss the behaviour of the tsunami waves within the archipelago, and evidence contrasting responses depending on the arrival azimuths. These results show that, for a given initial seismic energy, the tsunami amplification in remote bays is highly dependent on the source location and fault strike.
Oxalis simplicifolia (Oxalidaceae), an unusual new unifoliolate species from the Marquesas Islands (French Polynesia)
David Lorence,Warren Wagner
PhytoKeys , 2011, DOI: 10.3897/phytokeys.4.1604
Abstract: Oxalis simplicifolia Lorence & W. L. Wagner sp. nov., a new species from the Marquesas Islands (Ua Huka) is described and illustrated. It differs from the other Marquesas species, O. gagneorum, insimple, unifoliolate glabrous leaves, minutely glandular-puberulent calyx lobes, shorter corolla lobes, erect capsules, and smaller seeds. As its habitat is under serious threat from human impact, feral animals, and weeds, we concluded this new species should be added to the IUCN Red List as critically endangered (CR).
Revision of Kadua (Rubiaceae) in the Marquesas Islands, French Polynesia, with description of the new species K. lichtlei  [cached]
David Lorence,Warren Wagner
PhytoKeys , 2011, DOI: 10.3897/phytokeys.4.1601
Abstract: Kadua lichtlei Lorence & W. L. Wagner, sp. nov., a new species from Ua Huka, Marquesas Islands, is described and illustrated. This new species differs from the three other Marquesan Kadua species by its broadly elliptic to broadly ovate or subcircular leaf blades as well as much smaller and more numerous (80-300) flowers and smaller capsules. Known from a single population of about 30 individuals, we conclude this new species should be added to the IUCN Red List as critically endangered (CR). A key, amended descriptions, conservation status, and specimen citations for the three previously described Marquesan species, Kadua lucei, K. nukuhivensis, and K. tahuatensis are also provided.
Dengue 1 Diversity and Microevolution, French Polynesia 2001–2006: Connection with Epidemiology and Clinics  [PDF]
Elodie Descloux ,Van-Mai Cao-Lormeau,Claudine Roche,Xavier De Lamballerie
PLOS Neglected Tropical Diseases , 2009, DOI: 10.1371/journal.pntd.0000493
Abstract: Background Dengue fever (DF) is an emerging infectious disease in the tropics and subtropics. Determinants of DF epidemiology and factors involved in severe cases—dengue haemorrhagic fever (DHF) and dengue shock syndrome (DSS)—remain imperfectly characterized. Since 2000, serotype 1 (DENV-1) has predominated in the South Pacific. The aim of this study was (i) to determine the origin and (ii) to study the evolutionary relationships of DENV-1 viruses that have circulated in French Polynesia (FP) from the severe 2001 outbreak to the recent 2006 epidemic, and (iii) to analyse the viral intra-host genetic diversity according to clinical presentation. Methodology/Principal Findings Sequences of 181 envelope gene and 12 complete polyproteins of DENV-1 viruses obtained from human sera in FP during the 2001–2006 period were generated. Phylogenetic analysis showed that all DENV-1 FP strains belonged to genotype IV–“South Pacific” and derived from a single introduction event from South-East Asia followed by a 6-year in situ evolution. Although the ratio of nonsynonymous/synonymous substitutions per site indicated strong negative selection, a mutation in the envelope glycoprotein (S222T) appeared in 2002 and was subsequently fixed. It was noted that genetic diversification was very significant during the 2002–2005 period of endemic DENV-1 circulation. For nine DF sera and eight DHF/DSS sera, approximately 40 clones/serum of partial envelope gene were sequenced. Importantly, analysis revealed that the intra-host genetic diversity was significantly lower in severe cases than in classical DF. Conclusions/Significance First, this study showed that DENV-1 epidemiology in FP was different from that described in other South-Pacific islands, characterized by a long sustained viral circulation and the absence of new viral introduction over a 6-year period. Second, a significant part of DENV-1 evolution was observed during the endemic period characterized by the rapid fixation of S222T in the envelope protein that may reflect genetic drift or adaptation to the mosquito vector. Third, for the first time, it is suggested that clinical outcome may be correlated with intra-host genetic diversity.
Evaluation of far-field tsunami hazard in French Polynesia based on historical data and numerical simulations  [PDF]
A. Sladen,H. Hébert,F. Schindelé,D. Reymond
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2007,
Abstract: The first tsunami hazard map of French Polynesia is presented here on the basis of historical data, and numerical simulations. French Polynesia, because of its central position in the most tsunami prone ocean, the Pacific, is strongly exposed to far-field tsunamis. As no previous study on the area had been conducted, we compiled catalogues of all the historical observations (14 events), and tide gauges records (69 marigrams). The catalogues emphasise the higher hazard associated to the Marquesas archipelago, but also the deficiency of robust data in most other parts of French Polynesia. The recourse to numerical simulations allowed us to complement the existing records, and to test tsunami scenarii over different bathymetry and topography configurations, representative of the diversity of islands in French Polynesia. The tsunami hazard map assigns a high exposure level to the Marquesas and the island of Rurutu. Other islands of the Austral, and the Gambier archipelago have a elevated level of exposure, as well as three islands of Society: Tahiti, Moorea, and Huahine. All other islands of French Polynesia are considered as moderately exposed.
High Genetic Diversity Despite the Potential for Stepping-Stone Colonizations in an Invasive Species of Gecko on Moorea, French Polynesia  [PDF]
Maria A. Tonione, Natalie Reeder, Craig C. Moritz
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0026874
Abstract: Invasive species often have reduced genetic diversity, but the opposite can be true if there have been multiple introductions and genetic admixture. Reduced diversity is most likely soon after establishment, in remote locations, when there is lower propagule pressure and with stepping-stone colonizations. The common house gecko (Hemidactylus frenatus) was introduced to Moorea, French Polynesia in the remote eastern Pacific within the last two decades and accordingly is expected to exhibit low diversity. In contrast, we show that H. frenatus on Moorea has exceptionally high genetic diversity, similar to that near the native range in Asia and much higher than reported for other Pacific island reptiles. The high diversity in this recently founded population likely reflects extensive genetic admixture in source population(s) and a life history that promotes retention of diversity. These observations point to the importance of understanding range-wide dynamics of genetic admixture in highly invasive species.
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