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1.
Question: How rapidly has the sandy beach and maritime forest vegetation on Phuket recovered and regenerated after the impact of the major Indian Ocean tsunami of 2004? What are the characteristics of sandy beach species for regenerating their populations and the invasion patterns of originally non-sandy beach species or other newcomers after the tsunami? Location: Phuket Island, southern Thailand. Methods: Species composition of beaches was studied on the same research plots 6 months before and 9 months after the tsunami. The changes in individual species cover before and after the tsunami were determined by χ2 tests. Change in community composition was analysed by detrended correspondence analysis. The relationship between species and environmental factors was analysed by canonical correspondence analysis. Results: The sites disturbed by the tsunami were often invaded by annuals, especially grasses and asteraceous plants, rather than by perennials. In contrast, species with clonal growth by stolons decreased significantly. Factors determining the species habitat differences were soil hardness (penetration resistance of sandy soil), per cent silt content, soil water content and beach management. Habitat differences among originally non-sandy beach herbaceous species that expanded their population or moved to the coast after the disaster were defined by sand accretion or erosion caused by the tsunami. Many sandy beach herbaceous communities changed into Dactyloctenium aegyptium communities because of the tsunami were originally constituted by non-sandy beach D. aegyptium with Cenchrus echinatus. Although the forest floors of most maritime forests were invaded by originally non-sandy beach Tridax procumbens, Eleusine indica or D. aegyptium because of the tsunami, this did not result in a change in the vegetation unit, because species' loss was restricted to the understorey. In time, these forests will recover their previous community composition. Conclusions: Our results suggest that originally non-sandy beach native species invaded the disturbed beaches rapidly after the tsunami but their habitats differ. Sites where sand accumulated on a beach because of the tsunami were invaded by D. aegyptium and E. indica, whereas soil erosion permitted invasion by Digitania adscendens. Tridax procumbens establishes rapidly on wet sites with hard soil, high per cent silt content and low beach management pressure. Sandy beach species with subterranean long rhizomes are strongly tolerant of such disasters. We concluded that the species composition of the beaches disturbed by a temporary large disaster is determined by dormancy and growth forms, with radicoid form being influential.  相似文献   

2.
The abundance and diversity of species of microfungi was investigated on the beaches of Delfines, Km 24 Veracruz-Alvarado Highway, and El Coco, located on the coasts of the Caribbean Sea, Gulf of Mexico, and the Pacific Ocean, respectively. On each beach a sample composed of sand, subtidal wood or washed-up detritus with moist sand was collected. The samples were analyzed by three different methods, resulting in a total of 1,160 occurrences that fluctuated between 340 and 441 occurrences/sample. The number of species/sample fluctuated between 20 and 32. A total of 52 species was found, of which 12 were marine, and 40 nomarine, of terrestrial origin, and of these 15 were ascomycetes, 34 were hyphomycetes, 2 were blastomycetes and one was a coelomycete. The abundance distribution showed few species with high or low values, with the greates proportion having intermediate values. In order to compare species diversity among the samples frequency curves were utilized, based on the number of species expected from samples taken at random; the results showed that the beach at El Coco was richest in species.  相似文献   

3.
Background and AimsThe beach strawberry, Fragaria chiloensis, is found in a narrow coastal band from the Aleutian Islands to central California and then jumps thousands of kilometres all the way to Hawaii and Chile. As it probably had a North American origin, it must have been introduced to the other locations by long-distance dispersal. The aim of this study was to determine which agent carried the beach strawberry to its Pacific and South American locations.MethodsA deductive framework was constructed to separate between the possible modes of long-distance dispersal involving animals, wind and ocean currents. Bird migration was subsequently identified as the most likely scenario, and then the routes, habitats, feeding preferences and flight distances of all the shorebird species were evaluated to determine the most likely carrier.Key ResultsSix species migrate between North America and Chile and feed on the beaches and rocky shores where F. chiloensis grows naturally: Black-bellied Plovers, Greater Yellowlegs, Ruddy Turnstones, Sanderlings, Whimbrels and Willets. Of these, only two eat fruit and migrate in long continuous flight: Ruddy Turnstones and Whimbrels. Two species travel between North America and Hawaii, eat fruit and forage on the beaches and rocky shores where F. chiloensis grows naturally: Pacific Golden-plovers and Ruddy Turnstones. Ruddy Turnstones eat far less fruit than Pacific Golden-plovers and Whimbrels, making them less likely to have introduced the beach strawberry to either location.ConclusionsWe provide evidence that F. chiloesis seeds were probably dispersed to Hawaii by Pacific Golden-plovers and to Chile by Whimbrels.  相似文献   

4.

Parasitism by isopods is a common phenomenon in marine fishes and may induce negative effects, especially in juvenile stages. The surf-zones of sandy beaches are an important nursery habitat for many fish species, including commercially important ones, and are structured by beach characteristics and human activities, which are suggested to influence the fishes’ susceptibility to parasitism. Here, we analyze the early infestation and prevalence of parasitism in surf zones fishes of 27 beaches in southeastern Brazil with different characteristics. Parasites were recorded in only seven of the beaches. A high infestation was found in a single site, the highly urbanized Itaguá beach, where the prevalence of parasitism on juveniles and early adults of the Atlantic anchoveta Cetengraulis edentulus was high (68.11%). Four species of parasitic isopods were found, all belonging to the Cymothoidae family, but Livoneca desterroensis was the most abundant (78.7%). No effects of parasitism were detected on the size, weight and physiological condition of fishes, but presence of parasites and prevalence of infestation were positively affected by urbanization. Overall, our results indicate that the surf-zones have low parasite infestation, yet, they suggest that anthropic effects such as urbanization may enhance the prevalence of isopod parasitism.

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5.
Rhinochimaera pacifica is redescribed and a specimen from Tokyo Bay is designated as the neotype. A second species of the genus,R. africana, is newly recognized from Japan. A new scheme of measurements of the lateral line canals has been developed, and a comparison of proportional measurements of the snout width, eye length, and canal measurements clearly distinguishesR. pacifica andR. africana. Intraspecific variation ofR. pacifica and comparison ofR. pacifica andR. africana is discussed.Rhinochimaera pacifica has an irregular distribution in the north and south Pacific Ocean and Indian Ocean. This study also confirms a much wider range forR. africana than previously known and extends the range to the northern Pacific Ocean around the Japanese Archipelago.  相似文献   

6.
Sandy and shingle beaches were investigated in 2009 and 2010 along the coast of the Baltic Sea in northern Germany with the purpose of assessing biodiversity gradients from shingle to sandy beaches, from beach to primary dunes, and the impacts of tourism on biodiversity. On nine beach sites, ranging between 100% shingle and 99% sand without shingle, Carabidae, Staphylinidae, and Araneae were studied. Two of the six sandy beaches were open and four were closed to tourists. Additionally, trampling effects from tourists, species richness of plants, and plant cover were investigated on sixteen beaches. According to results, primary dunes showed higher species richness in carabids and spiders, but not in staphylinds. Shingle beaches exhibited lower species richness in Staphylinidae and Araneae, but not in Carabidae. As estimated by the Jackknife II method, shingle beaches were the lowest in total species richness. Trampling intensity ranged from 0 footprints m−2 day−1 on closed beaches, up to a maximum of 30 footprints m−2 day−1. On “intensively” used beaches (12 footprints m−2 day−1, on average), reduction of plant cover was more pronounced than on “extensively” used beaches (7 footprints m−2 day−1, on average). Both plant cover and plant species richness were lower on intensively and extensively used beaches than on closed beaches. In arthropods, only staphylind and spider species richness was significantly lower on open beaches than on closed beaches, but no differences were found in carabids. Referring to our results, trampling effects from tourists have high impact on species richness of sandy beaches, on both intensively and extensively used sites.  相似文献   

7.
Summary (1) A total of 312 soils, 271 from New Zealand, 24 from Rarotonga, Cook Islands and 17 from Tokelau Islands was examined by the hair-baiting technique.(2)Microsporon gypseum was isolated from 1.5% of New Zealand soils and from 36.6% of Pacific Island soils. The difference in incidence in the two areas is significant.(3)Keratinomyces ajelloi andMicrosporon cookei were recovered from 52.8% and 7.7% of New Zealand soils respectively but neither species was isolated from the Island samples.K. ajelloi was found to be significantly associated with strongly acid soils, andM. cookei with a farmyard substrate.(4)Trichophyton terrestre was isolated from 1.1% of New Zealand and from 12.2% of Pacific Island soils. Two strains ofChrysosporium keratinophilum were isolated from New Zealand soils and an unidentifiedChrysosporium from one Rarotongan sample.(5) The distribution of the different species is discussed and compared with those reported in surveys carried out in other countries of the Southern Hemisphere. The effects of ambient temperature, and source and pH of the soil, on the distribution of keratinophilic fungi are considered, but there is insufficient detailed evidence to determine the importance of these factors in the ecology of these organisms.  相似文献   

8.
Tubificid and enchytraeid oligochaetes are common members of the interstitial fauna of sandy beaches. Their abundance dynamics, life cycles and distribution patterns were investigated at two beaches on the western Baltic Sea and at a North Sea beach (Isle of Sylt). Populations of 115,000 ind./m2 were found at protected Baltic beaches. Reproduction of the tubificids, Phallodrilus monospermathecus and Spiridion insigne takes place within a well defined breeding period once a year. The market horizontal and vertical distribution patterns of various tubificid and enchytraeid species are elucidated by preference reactions to several physiographic parameters, such as oxygen and water content of the sediment, and salinity.  相似文献   

9.
Park  Taisoo 《Hydrobiologia》1994,(1):317-332
The geographic distribution of the bathypelagic calanoid genus Paraeuchaeta was investigated by examining midwater trawl and plankton net samples collected mostly from depths exceeding 1000 m throughout the world's oceans. Of the 81 species referred to Paraeuchaeta, the geographic ranges of about 50 species could be defined with reasonable certainty. Contrary to early authors, the number of species having a worldwide distribution was surprisingly small (12 species or 15% of the 81 species of the genus) as compared to common species endemic to various geographic regions (34 species or 42% of the total of 81). Almost twice as many species were found in the Indo-Pacific Ocean as in either the Atlantic or the Southern Ocean. Faunistically, the northern Atlantic, mid-Atlantic, northern Pacific, East Pacific, Indo-West Pacific, and Southern Ocean were distinct in terms of endemic species. A number of species were found to be endemic to highly productive areas, where they were usually very abundant. Rare species, on the other hand, were generally found to be widely distributed, although some were too rare for their range to be determined with certainty. To explain these findings, the following hypothesis is proposed: Bathypelagic calanoids endemic to and abundant in eutrophic areas are those adapted to eutrophic conditions of their habitats and therefore cannot expand their ranges into contiguous oligotrophic waters even if the other environmental conditions are favorable. Other species, on the other hand, generally have extensive geographic ranges because of their survival ability in widely expanding oligotrophic conditions and the absence of physicochemical barriers at bathypelagic depths of the world's oceans.  相似文献   

10.
ABSTRACT

Marine strandlines provide habitat for a variety of littoral and terrestrial invertebrates, including arachnids. In this study we recorded spiders in strandlines at 35 sites on Banks Peninsula, New Zealand. On average, only 1.5 named species were recorded per thirty-minute hand search, and many sample visits (30%) recorded no spiders. Species accumulation curves suggested further species could be recorded with further sampling, but these may be tourist species rather than strandline residents. Thirty-eight species were recorded in total, with the introduced theridiid Steatoda capensis being the most common (30 records) and widespread (17 locations). The New Zealand endemic species Otagoa nova (25 records) (Toxopidae), Anoteropsis litoralis (15) and Anoteropsis hilaris (15) (Lycosidae), and the introduced Tenuiphantes tenuis (24) (Linyphiidae), were also common. Spiders were more frequent in strandlines on boulder beaches compared with shingle beaches, although there was no statistical differences in the numbers of species recorded on the different beach types.  相似文献   

11.
Excirolana braziliensis is a dioecious marine isopod that lives in the high intertidal zone of sandy beaches on both sides of Central and South America. It possesses no larval stage and has only limited means of adult dispersal. Indirect estimates of gene flow have indicated that populations from each beach exchange less than one propagule per generation. Multivariate morphometrics have discovered three morphs of this species in Panama, two of them closely related and found on opposite sides of Central America (“C morph” in the Caribbean and “C′ morph” in the eastern Pacific), the third found predominantly in the eastern Pacific (“P morph”). Though the P and C′ morphs are seldom found on the same beach, they have overlapping latitudinal ranges in the eastern Pacific. A related species, Excirolana chamensis, has been described from the Pacific coast of Panama. Each beach contains populations that remain morphologically and genetically stable, but a single drastic change in both isozymes and morphology has been documented. We studied isozymes and multivariate morphology of 10 populations of E. braziliensis and of one population of E. chamensis. Our objective was to assess the degree of genetic and morphological variation, the correlation of divergence on these two levels of integration, the phylogenetic relationships between morphs, and the possible contributions of low vagility, low gene flow, and occasional extinction and recolonization to the genetic structuring of populations. Genetic distance between the P morph, on one hand, and the other two morphotypes of E. braziliensis, on the other, was as high as the distance between E. braziliensis and E. chamensis. Several lines of evidence agree that E. chamensis and the P morph had diverged from other morphs of E. braziliensis before the rise of the Panama Isthmus separated the C and C′ forms, and that the P morph constitutes a different species. A high degree of genetic differentiation also exists between populations of the same morph. On the isozyme level, every population can be differentiated from every other on the basis of at least one diagnostically different locus, regardless of geographical distance or morphological affiliation. Morphological and genetic distances between populations are highly correlated. However, despite the high degree of local variation, evolution of E. braziliensis as a whole has not been particularly rapid; divergence between the C and C′ morphs isolated for 3 million yr by the Isthmus of Panama is not high by the standard of within-morph differentiation or by comparison with other organisms similarly separated. Alleles that are common in one population may be absent from another of the same morph, yet they appear in a different morph in a separate ocean. The high degree of local differentiation, the exclusive occupation of a beach by one genotype with rare arrival of foreign individuals that cannot interbreed freely with the residents, the genetic stability of populations with infrequent complete replacement by another genetic population, and the sharing by morphs of polymorphisms that are not shared by local populations, all suggest a mode of evolution concentrated in rare episodes of extinction and recolonization, possibly coupled with exceptional events of gene flow that help preserve ancestral variability in both oceans.  相似文献   

12.
ABSTRACT

The brightly blue shallow water species Terpios fugax Duchassaing and Michelotti, 1864 was originally described from the Caribbean and has been extensively recorded in the Atlantic Ocean, but rarely found in the Indian and Pacific Oceans. In the Pacific Ocean it has been only reported from Sulawesi, Indonesia and from the Caroline and Marshall Islands. Here we report the first record of Terpios in the Eastern Pacific, based on the presence of T. fugax at Caldera, Región de Atacama, northern Chile. Although this species may have been inadvertently introduced to the area by human activity, it should also be considered that the geographically distant populations of this sponge (from the Caribbean to the Eastern Pacific) may represent different species.  相似文献   

13.
The Antarctic fur seal Arctocephalus gazella at Gough Island (40°20′S, 09°54′W) in the South Atlantic Ocean, first seen in October/November 2005, was recorded again in September–October 2009. Up to three different individual Antarctic fur seals were sighted on a single day, on a particular beach. A total of seven different individuals were recorded over a 3-week period, well before the onset of the breeding (pupping) season of the resident population of Subantarctic fur seals A. tropicalis. Positively identified individuals were all male, mostly subadult and lean. Only a fraction (~20%) of the available beaches was searched, and it is unknown if the Antarctic fur seals were still present at Gough Island during the austral summer breeding season of southern fur seals.  相似文献   

14.
Aim We address questions about trans‐Pacific distributions of marine organisms and the North Pacific Ocean as a centre of marine biodiversity through a phylogenetic and biogeographical study of a pan‐Pacific genus of Northern Hemisphere smelts (Hypomesus, Pisces: Osmeridae). Location North Pacific Ocean. Methods Relationships of the five species of Hypomesus from throughout the North Pacific were reconstructed through maximum likelihood and Bayesian phylogenetic analyses of sequence data from two mitochondrial (cytb, 16S) and three nuclear (ITS2, S71, RAG1) gene regions of five to 25 individuals per species, totalling 3588 characters. The resulting phylogenies were used to test hypotheses of species relationships and geographical origins using both dispersal‐based and maximum likelihood methods for inferring ancestral areas (lagrange ). Cytb sequence divergence and a Bayesian approach (beast ) were used to estimate the timeframe of Hypomesus evolution, which was compared with work on similarly distributed taxa. Results Hypothesized trans‐Pacific Ocean relationships based on lateral line scale counts were not supported by the phylogeny, suggesting parallel evolution of this phenotype, although we found one such relationship between the western H. japonicus and the two eastern Pacific species (H. pretiosus and H. transpacificus). Dispersalist approaches rejected an early proposal of a double‐compression vicariant mechanism as well as an eastern Pacific origin. Results from the lagrange analysis suggested a more widespread ancestor, although also supporting a role for the western Pacific. Divergence estimates suggested that most splits between species occurred in the mid‐Miocene, and the most recent speciation event, between the eastern Pacific species, occurred in the Pliocene to early Pleistocene. Main conclusions Our molecular data indicate that the character historically used to define relationships within Hypomesus, lateral line scale count, does not reflect ancestry within the genus. Biogeographical reconstructions suggest an important role for the western North Pacific in the diversification of Hypomesus. While uncertainty remains over the date of origin for this genus, estimates place the divergences during periods of climatic cooling that have been important in generating diversity in a number of similarly distributed organisms. Additional comparative data will provide further insight into the relative importance of the western region in generating diversity in the North Pacific Ocean.  相似文献   

15.
We have investigated how indices of beach health perform in predicting the abundances of the crustaceans Emerita brasiliensis and Atlantorchestoidea brasiliensis from 22 metropolitan beaches in the cities of Rio de Janeiro and Niterói. Urbanization, Recreation and Conservation indices were used to assess sandy beaches health. Grain size and beach slope were used as morphodynamics indicators. Diagram from the principal component analysis clearly separated beaches with different urbanization and conservation levels. Generalized additive models (GAM's) were adjusted for species abundance using the indices and morphodynamic parameters as explanatory variables. Lower abundances were predicted for beaches with high levels of urbanization, whereas predictions of higher abundances occurred on beaches with high conservation levels. Using theoretic inference we showed that the urbanization index was the most important predictor for abundance of A. brasiliensis and the conservation index was the most important predictor for E. brasiliensis, reflecting different responses by upper tidal and intertidal species. A. brasiliensis occupies the intermediate and upper beach zones and E. brasiliensis is a swash zone filter-feeder that is more abundant in pristine beaches. Both species are highly subject to the impact of bathers and coastal modification. Unexpected, the recreation index did not show a negative effect on abundance predictions. Urbanization and conservation indices can be suitable metrics to measure anthropogenic effects on macrobenthic species. Moreover, mole crabs and sandhoppers species can be easily monitored. Coastal urbanization is a global phenomenon and we used the diagram of urbanization and conservation levels to expose possible directions for management strategies of metropolitan sandy beaches.  相似文献   

16.
Vesicular-arbuscular mycorrhizal fungi (VAMF) were a nearly constant component of the coastal strand of the Hawaiian Islands, occurring in beach sand, driftline debris, in roots of 23 of 31 species of vascular plants examined, and in association with rhizomes of two native species, Sporobolus virginicus and Jacquemontia sandwicensis. Mycorrhizae were most frequent and intensity of VAM development was greatest in endemic plants, less in indigenous species, and least in alien species. Spores of VAMF were produced in abundance between the rhizome and the leaf sheaths of Sporobolus. Roots of two strand species, including roots of Sporobolus that were immersed in seawater for 7 days, functioned as inocula of VAMF in pot-culture studies. The close association between propagules of VAMF and vegetative fragments of indigenous plants found in the present study suggests a mechanism of codispersal that appears to ensure the maintenance of the symbiosis in nutrient-deficient sites where it is most beneficial. The codispersal of fungus and plant may explain the high frequency of mycotrophy in strand species in the tropical Pacific.  相似文献   

17.
Aulopus bajacali, described from the eastern Pacific Ocean from a single specimen, is redescribed. It is now known from over 400 specimens. It is the only Pacific species ofAulopus belonging with the Atlantic species group ofA. nanae, A. filamentosus, andA. cadenati. It shares a short dorsal-fin base and some color pattern characters with this group. New distribution records from Ecuador and the Galapagos Islands extend its range; it is now known from mid-Baja California (25°N) to about 3°S in the eastern central Pacific.  相似文献   

18.
The blue shark (Prionace glauca) and the shortfin mako shark (Isurus oxyrinchus) are two large and highly migratory sharks distributed in most oceans. Although they are often caught in the south Pacific Ocean long-line fisheries, their trophic ecology is poorly understood. Stable isotopes with Bayesian mixing and dependence concentration models were performed to determine the diet and trophic differences between the two species in the South-eastern Pacific Ocean. According to the mixing models, fishes are the most important prey of these sharks. Dolphin calves and remains were found in the stomachs of both species, which represents a novel finding in trophic ecology of South Pacific sharks. Intra-specific differences were found in P. glauca, but not in specimens of I. oxyrinchus. The two sharks showed a high degree of diet overlap (73%), primarily over mackerel and dolphin carcasses. Our results indicate that blue and shortfin mako sharks have a generalist feeding strategy in the eastern Pacific Ocean, with a strong preference for teleost fishes and also for dolphin carcasses. Therefore, trophic studies are useful to understand energy flow through the food web, and the trophic position of key species.  相似文献   

19.
The second part of the publication is devoted to the Melamphaes species (family Melamphaidae), which are characterized by 20 and more rakers on the first gill arch, by seven soft rays in the ventral fin, by absence of a temporal spine, by 14–15 rays in the pectoral fin, and by 11 abdominal vertebrae. M. polylepis is characterized by circumtropical range (Atlantic Ocean, Indian Ocean, western and central Pacific Ocean). Newly described species M. falsidicus is described from the northern Atlantic Ocean, where it was sampled between 34°N and 58°N. Before, this species was defined as M. microps. Another newly described species, M. pachystomus, is described along the Peruvian Coast. M. macrocephalus is redescribed. This species inhabits the eastern tropical Pacific Ocean (approximately between 30°N and 23°S). One of the studied specimens of M. macrocephalus was characterized by larger body size (SL = 128 mm) than was described before for this species. M. leprus is known currently by single findings from the eastern tropical Atlantic Ocean (between 11°N and 4°S). This species was also found in the samples obtain in the Gulf of Guinea.  相似文献   

20.
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