共查询到20条相似文献,搜索用时 0 毫秒
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In July 1997, conspicuous white patches of necrotic tissue and bare skeleton began to appear on scleractinian corals in several bays around St. John, US Virgin Islands. Analysis of diseased coral tissue from five different species confirmed the presence of a Sphingomonas-like bacterium, the pathogen for plague type II. To date, 14 species of hard corals have been affected by plague type II around St. John. This disease was monitored at Haulover and Tektite Reefs at depths of 7-12 meters. The study site at Tektite Reef has > 50% cover by scleractinian corals with 90% of hard corals being composed of Montastraea annularis. Monthly surveys at Tektite Reef from December 1997 to May 2001 documented new incidence of disease (bare white patches of skeleton) every month with associated loss of living coral and 90.5% of all disease patches occurred on M. annularis. The frequency of disease within transects ranged from 3 to 58%, and the area of disease patches ranged from 0.25 to 9000 cm2. The average percent cover by the disease within 1 m2 ranged from 0.01% (+/- 0.04 SD) to 1.74% (+/- 9.08 SD). Photo-monitoring of 28 diseased corals of 9 species begun in September 1997 at Haulover Reef revealed no recovery of diseased portions with all necrotic tissue being overgrown rapidly by turf algae, usually within less than one month. Most coral colonies suffered partial mortality. Very limited recruitment (e.g., of Agaricia spp., Favia spp. and sponges) has been noted on the diseased areas. This coral disease has the potential to cause more loss of live coral on St. John reefs than any other stress to date because it targets the dominant reef building species, M. annularis. 相似文献
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To test the hypotheses that U.S. Virgin Islanders' knowledge about local coral reefs is correlated with behavior, and that different sociological groups of residents have different patterns of knowledge and behavior, a mixed approach to surveying residents was used: (1) personal interviews were held in public locations and (2) an online version of the survey was administered to residents of the U.S. Virgin Islands. From July-October 2008,462 residents over 18 years old were surveyed. Results indicate that people who engaged in outdoor activities knew significantly more about coral reefs (Spearman p < 0.01, r2 = -0.128). Those more knowledgeable about coral reefs engaged in more positive stewardship activities (e.g. beach clean-ups) (Spearman p < 0.01, r2 = 0.127). Negative behaviors (e.g. anchoring on reef) were not significantly correlated with increased knowledge of coral reefs (Spearman p = -0.911, r2 = -0.000025). Fishers did not have greater ability in identifying Acropora palmata coral than non-fishers (chi2 = 4.138, p = 0.126); however, swimmers, snorkelers and divers (as a class) were more able to identify A. palmata than non-swimmers (chi2 = 9.764, p = 0.002). Most residents identified sea turtle species as endangered (hawksbill turtle, 78.9%) but only 48.2% of the responses included Acropora spp. as threatened. Resident attitudes towards conservation of local resources were overwhelmingly positive. 相似文献
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By E. C. Franklin C. V. Brong A. R. Dow M. T. Craig 《Zeitschrift fur angewandte Ichthyologie》2009,25(5):616-617
Length–weight and length–length relationships are presented for three species of butterflyfish endemic to the Hawaiian Islands and Johnston Atoll. From specimens collected within the Papahānaumokuākea Marine National Monument (PMNM), the weight–length relationships were determined for Chaetodon fremblii as W = 0.029SL3.17 , Chaetodon miliaris as W = 0.042 SL3.00 , and Chaetodon multicinctus as W = 0.029SL3.19 where weight, W , is reported in grams and standard length, SL, in centimeters. Length-frequency data and equations to calculate total length from standard length are also presented. 相似文献
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Daniel H. Green 《Journal of experimental marine biology and ecology》2011,397(2):220-229
In this study, coral recruitment was measured on a kilometer-wide scale over two years on shallow (5-6 m depth) fringing reefs in St. John, US Virgin Islands, with the objective of determining the extent to which variation in recruitment was affected by biophysical coupling involving temperature and flow. Coral recruitment was measured using settlement tiles deployed at 10 sites along 10 km of shore. The tiles were first deployed in August 2006, and thereafter replaced every ≈ 6 months to sample from either August to January, or January to August over 2 years. Seawater temperature was recorded at the 10 sites using logging thermistors, and flow was quantified using drogues. Overall, corals recruited at a rate equivalent to 76 corals m− 2 6 months− 1, and were represented mostly by poritids (43% of recruits), agaricids (29%), faviids (17%) and siderastreids (7%). Although the density of recruits differed among sites in a pattern that varied among periods and years, there was a consistent trend for mean density to decline from ≈ 4 corals tile− 1 at eastern sites, to ≤ 1 coral tile− 1 at western sites. One aspect of seawater temperature - the daily range - differed among sites and was greater at western compared to eastern sites, and while it was related inversely to recruitment over one of the sampling periods, it was equivocal as a physical process affecting recruitment. Instead, our results are consistent with biophysical coupling involving patch depletion and downstream filtering, whereby patches of coral larvae are delivered to the south shore of St. John and depleted of larvae through settlement as the water progresses westward. 相似文献
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DUNN E 《The Annals of applied biology》1949,36(4):525-534
Colorado beetles can survive up to 10 days in sea water and still be capable of flying when the temperature reaches 80° F. (26·67° C.). The beetles that reached the Channel Islands in May 1947 and in May 1948 prove that they can travel across about 30 miles of sea, the approximate distance of Guernsey from the Cherbourg peninsula. The invasions occurred as a result of migrant beetles from the Cherbourg peninsula which dropped on the sea between the Channel Islands and the French coast and drifted ashore. 相似文献
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Floristic biogeography of the Hawaiian Islands: influences of area, environment and paleogeography 总被引:1,自引:1,他引:1
Jonathan P. Price 《Journal of Biogeography》2004,31(3):487-500
Aim A detailed database of distributions and phylogenetic relationships of native Hawaiian flowering plant species is used to weigh the relative influences of environmental and historical factors on species numbers and endemism. Location The Hawaiian Islands are isolated in the North Pacific Ocean nearly 4000 km from the nearest continent and nearly as distant from the closest high islands, the Marquesas. The range of island sizes, environments, and geological histories within an extremely isolated archipelago make the Hawaiian Islands an ideal system in which to study spatial variation in species distributions and diversity. Because the biota is derived from colonization followed by extensive speciation, the role of evolution in shaping the regional species assemblage can be readily examined. Methods For whole islands and regions of each major habitat, species–area relationships were assessed. Residuals of species–area relationships were subjected to correlation analysis with measures of endemism, isolation, elevation and island age. Putative groups of descendents of each colonist from outside the Hawaiian Islands were considered phylogenetic lineages whose distributions were included in analyses. Results The species–area relationship is a prominent pattern among islands and among regions of each given habitat. Species number in each case correlates positively with number of endemics, number of lineages and number of species per lineage. For mesic and wet habitat regions, island age is more influential than area on species numbers, with older islands having more species, more single‐island endemics, and higher species : lineage ratios than their areas alone would predict. Main conclusions Because species numbers and endemism are closely tied to speciation in the Hawaiian flora, particularly in the most species‐rich phylogenetic lineages, individual islands’ histories are central in shaping their biota. The Maui Nui complex of islands (Maui, Moloka‘i, Lāna‘i and Kaho‘olawe), which formed a single large landmass during most of its history, is best viewed in terms of either the age or area of the complex as a whole, rather than the individual islands existing today. 相似文献
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Geranium hanaense, a new species endemic to two small montane bogs (20 ha total) on northeast Haleakala, Maui, Hawaiian Islands, is described. This new species is postulated to have evolved from the high elevation xeromorphic species,G. cuneatum, in a fashion similar to that of the two other bogGeranium species. The ecology and evolution of HawaiianGeranium species, includingG. hanaense, are discussed. 相似文献
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Species introductions into novel habitats, especially island ecosystems, can have devastating effects on ecosystem function
and stability. Though none are native, at least 96 aphid species can now be found on one or more of the Hawaiian Islands.
As aphids cause direct feeding damage and transmit plant viruses, it is important to identify the traits that have enabled
these particular species to successfully colonize the archipelago. To address this question, nine morphological and ecological
traits that may contribute to successful colonization were assessed for aphids present in Hawaii. As a comparative null model,
we assessed the same traits for heterospecific congeners which are not present in the archipelago, but are present elsewhere
in the world. Here we report that traits with higher frequencies among colonizing aphid species are: small apterae size, broad
host range, anholocycly (i.e., permanent parthenogenesis), and presence in continental USA. Small aphids arriving from the
mainland US and capable of feeding on numerous plant species may be intercepted less often by plant protection agents. It
is also likely that asexually reproducing species are well suited to the Hawaiian subtropical climate, thereby eliminating
the need for sexual phases and egg-laying for overwintering. By understanding the traits that enable aphids to successfully
colonize remote islands, it is our hope that plant protection efforts may be enhanced, thereby reducing damage to native ecosystems. 相似文献
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In the Hawaiian Islands, massive volcanoes have created extreme elevation gradients, resulting in environments ranging from nearly tropical to alpine, spread across a distance of only a few dozen kilometers. Although the Hawaiian Islands are widely recognized for opportunities to study lowland tropical forest invasions, less attention has been paid to invasions of Hawaii's upper-montane forest, sub-alpine and alpine environments. This study synthesizes current knowledge of plant naturalization in upper-montane environments of the Hawaiian Islands in order to (1) determine whether patterns of tropical versus temperate species invasion change with elevation, and (2) evaluate whether upper-montane invaders are having significant impacts on native plant communities. A total of 151 naturalized plant species have been recorded at 2000 m or higher. Most species (93%) are herbaceous, and over half (52%) are native to Europe/Eurasia. Twenty-one species (14%) are reported to be disruptive in native plant communities, mainly by forming dense stands that appear to inhibit recruitment of natives, but also by altering vegetation structure or causing changes in ecosystem processes. Fourteen species (9%) were first recorded within the past 30 years, indicating that new invasions of upper-montane habitats are ongoing. At 1200 m elevation, only 38% of naturalized species are temperate in origin, but the proportion of temperate species increases linearly with elevation up to 3000 m (alpine habitat), where all naturalized species are temperate in origin and over 80% are native to Europe/Eurasia. Declining temperature along the elevation gradient probably drives this pattern. The extreme elevation gradients in the Hawaiian Islands provide specific opportunities for comparative studies on the ecology and evolution of temperate invaders while also creating a unique field environment for understanding interactions between temperate and tropical species. 相似文献