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Highest Diversity (highest + diversity)
Selected AbstractsSpecies richness of marine Bryozoa in the continental shelf and slope off Argentina (south-west Atlantic)DIVERSITY AND DISTRIBUTIONS, Issue 1 2000Juan López Gappa Abstract., A total of 246 marine bryozoan species was recorded within an area of the south-west Atlantic between 35° and 56°S, and between the coast of Argentina and 50°W. The distribution pattern of benthic stations surveyed during the most important cruises in the area shows that the sampling effort has been biased towards southern shelf areas off Santa Cruz and Tierra del Fuego, as well as around the Malvinas (Falkland) islands. The littoral zone, Patagonian gulfs and the continental shelf off Chubut, Río Negro and Buenos Aires state received less attention, and should be surveyed more intensively in the future. Only 2% of the species can be regarded as non-indigenous, all of them inhabiting biofouling communities in harbour environments. With the exception of some thoroughly surveyed localities, the number of species recorded for different areas of the coast, shelf and slope is estimated to be just a small fraction of the actual number of species present. A distinct diversity gradient was found, with species-rich stations located only in the southern shelf. Highest diversity occurred in shelf areas dominated by coarse sediments, and along a high-productivity shelf-break front. A remarkable decrease in species richness was found in inner and middle shelf areas off Chubut, Río Negro and Buenos Aires state. This pattern may be related to the Pacific origin of the Magellanic fauna, since the diversity of bryozoans is higher in the Pacific than in the Atlantic Ocean. The trend of species richness is, however, overemphasized by the fact that the least diverse faunistic assemblage occurs in areas where surveys have been relatively less frequent. An up-to-date checklist of species recorded for the study area is included. [source] Testing the intermediate disturbance hypothesis: when will there be two peaks of diversity?DIVERSITY AND DISTRIBUTIONS, Issue 1 2005Karin Johst ABSTRACT Succession after disturbances generates a mosaic of patches in different successional stages. The intermediate disturbance hypothesis predicts that intermediate disturbances lead to the highest diversity of these stages on a regional scale resulting in a hump-shaped diversity,disturbance curve. We tested this prediction using field data of forest succession and hypothetical succession scenarios in combination with analytical and simulation models. According to our study the main factors shaping the diversity,disturbance curve and the position of the diversity maximum were the transition times between the successional stages, the transition type, neighbourhood effects and the choice of diversity measure. Although many scenarios confirmed the intermediate disturbance hypothesis we found that deviations in the form of two diversity maximums were possible. Such bimodal diversity,disturbance curves occurred when early and late successional stages were separated by one or more long-lived (compared to the early stages) intermediate successional stages. Although the field data which met these conditions among all those tested were rare (one of six), the consequences of detecting two peaks are fundamental. The impact of disturbances on biodiversity can be complex and deviate from a hump-shaped curve. [source] The mid-latitude biodiversity ridge in terrestrial cave faunaECOGRAPHY, Issue 1 2006David C. Culver The world's obligate cave-dwelling fauna holds considerable promise for biogeographic analysis because it represents a large number of independent evolutionary experiments in isolation in caves and adaptation to subterranean life. We focus on seven north temperate regions of at least 2000 km2, utilizing more than 4300 records of obligate cave-dwelling terrestrial invertebrates. In North America, highest diversity was found in northeast Alabama while in Europe highest diversity was found in Ariège, France, and in southeast Slovenia. Based on these regions as well as more qualitative data from 16 other regions, we hypothesize that a ridge (ca 42°,46° in Europe and 34° in North America) of high biodiversity occurs in temperate areas of high productivity and cave density. This may reflect a strong dependence of cave communities on long term surface productivity (as reflected in actual evapotranspiration), because the subterranean fauna relies almost entirely on resources produced outside caves. This dependence may explain the unique biodiversity pattern of terrestrial cave invertebrates. [source] Highly diverse community structure in a remote central Tibetan geothermal spring does not display monotonic variation to thermal stressFEMS MICROBIOLOGY ECOLOGY, Issue 1 2006Lau Chui Yim Abstract We report an assessment of whole-community diversity for an extremely isolated geothermal location with considerable phylogenetic and phylogeographic novelty. We further demonstrate, using multiple statistical analyses of sequence data, that the response of community diversity is not monotonic to thermal stress along a gradient of 52,83°C. A combination of domain- and division-specific PCR was used to obtain a broad spectrum of community phylotypes, which were resolved by denaturing gradient gel electrophoresis. Among 58 sequences obtained from microbial mats and streamers, some 95% suggest novel archaeal and bacterial diversity at the species level or higher. Moreover, new phylogeographic and thermally defined lineages among the Cyanobacteria, Chloroflexi, Eubacterium and Thermus are identified. Shannon,Wiener diversity estimates suggest that mats at 63°C supported highest diversity, but when alternate models were applied [Average Taxonomic Distinctness (AvTD) and Variation in Taxonomic Distinctness (VarTD)] that also take into account the phylogenetic relationships between phylotypes, it is evident that greatest taxonomic diversity (AvTD) occurred in streamers at 65,70°C, whereas greatest phylogenetic distance between taxa (VarTD) occurred in streamers of 83°C. All models demonstrated that diversity is not related to thermal stress in a linear fashion. [source] Genetic diversity of Chinese domestic goat based on the mitochondrial DNA sequence variationJOURNAL OF ANIMAL BREEDING AND GENETICS, Issue 1 2009Y.-P. Liu Summary The aim of this study was to characterize the genetic diversity of domestic goat in China. For this purpose, we determined the sequence of the mitochondrial DNA (mtDNA) control region in 72 individuals of the Yangtze River delta white goat, and reanalysed 723 published samples from 31 breeds/populations across China. All goat haplotypes were classified into four haplogroups (A,D) previously described. The phylogenetic pattern that emerged from the mtDNA control region sequence was confirmed by the analysis of the entire cytochrome b sequence of eight goats representative of the four haplogroups. It appeared that in Chinese domestic goat, haplogroups A and B were dominant and distributed in nearly all breeds/populations, while haplogroups C and D were only found in seven breeds/populations. Four breeds/populations contained all four haplogroups. When grouping the breeds/populations into five geographic groups based on their geographic distributions and ecological conditions, the southern pasturing area had the highest diversity whereas the northern farming area had the lowest diversity. 84.29% and 11.37% of the genetic variation were distributed within breeds and among breeds within the ecologically geographical areas, respectively; only 4% of genetic variation was observed among the five geographic areas. We speculate that the traditional seasonal pastoralism, the annual long-distance migrations that occurred in the past, and the commercial trade would account for the observed pattern by having favoured gene flows. [source] Relationships between fish assemblages, macrophytes and environmental gradients in the Amazon River floodplainJOURNAL OF FISH BIOLOGY, Issue 3 2003P. Petry During the flood season of 1992,1993, 139 species of fishes were collected from a floodplain lake system in the central Amazon Basin. Fish species distribution was examined relative to abiotic variables in seven vegetation strata on Marchantaria Island, Solimões River. Both environmental variables and species distributions were influenced by a river channel to floodplain-interior gradient. Species diversity was significantly higher in vegetated areas than in unvegetated areas, with deeper water Paspalum repens stands harbouring the highest diversity. As a result, species richness and catches were positively related to habitat complexity, while catch was also negatively related to dissolved oxygen (DO) and water depth. Low DO and shallow waters appeared to act as a refuge from predation. Fish assemblages were related to water chemistry, but species richness was not. Canonical correspondence analysis provided evidence that floodplain fish assemblages formed by the 76 most common species were influenced by physical variables, macrophyte coverage and habitat complexity, which jointly accounted for 67% of the variance of fish species assemblages. Omnivores showed no pattern relative to the river channel to floodplain-interior gradient while detritivores were more likely to be found at interior floodplain sites and piscivores closer to the river. Piscivores could be further separated into three groups, one with seven species associated with free-floating macrophytes in deep water, a second with five species found in shallow waters with rooted grasses and a third with six open water orientated species. The results suggest that fish assemblages in the Amazon floodplain are not random associations of species. [source] MORTUARY DISPLAY AND CULTURAL CONTACT: A CEMETERY AT KASTRI ON THASOSOXFORD JOURNAL OF ARCHAEOLOGY, Issue 4 2006SARA OWEN Summary. This article explores how the patterns of development within the local populations prior to Greek colonization, or even Greek contact, can elucidate the process of Greek colonization. Focusing upon the Thracian Early Iron Age cemetery of Kastri on Thasos, it suggests that past interpretations of such cemeteries as undifferentiated is due to the imposition of modern ideas of value. This article instead uses the criterion of diversity to suggest that the cemetery in fact has clear patterns of social differentiation in the first and last periods of use. Furthermore imports are restricted to graves of highest diversity in the last period of use (the early seventh century BC). This pattern is repeated over Early Iron Age Thrace, and is indicative of a social change within Thrace prior to Greek colonization which saw nascent Thracian elites seeking out imports from many areas in order to bolster their status. [source] Species richness and structure of three Neotropical bat assemblagesBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2008KATJA REX We compared the assemblages of phyllostomid bats in three Neotropical rainforests with respect to species richness and assemblage structure and suggested a method to validate estimates of species richness for Neotropical bat assemblages based on mist-netting data. The fully inventoried bat assemblage at La Selva Biological Station (LS, 100 m elevation) in Costa Rica was used as a reference site to evaluate seven estimators of species richness. The Jackknife 2 method agreed best with the known bat species richness and thus was used to extrapolate species richness for an Amazonian bat assemblage (Tiputini Biodiversity Station; TBS, 200 m elevation) and an Andean premontane bat assemblage (Podocarpus National Park; BOM, 1000 m elevation) in Ecuador. Our results suggest that more than 100 bat species occur sympatrically at TBS and about 50 bat species coexist at BOM. TBS harbours one of the most species-rich bat assemblages known, including a highly diverse phyllostomid assemblage. Furthermore, we related assemblage structure to large-scale geographical patterns in floral diversity obtained from botanical literature. Assemblage structure of these three phyllostomid assemblages was influenced by differences in floral diversity at the three sites. At the Andean site, where understorey shrubs and epiphytes exhibit the highest diversity, the phyllostomid assemblage is mainly composed of understorey frugivores and nectarivorous species. By contrast, canopy frugivores are most abundant at the Amazonian site, coinciding with the high abundance of canopy fruiting trees. Assemblage patterns of other taxonomic groups also may reflect the geographical distribution patterns of floral elements in the Andean and Amazonian regions. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94, 617,629. [source] Mesozoic Evaniidae (Insecta: Hymenoptera) in Spanish Amber: Reanalysis of the Phylogeny of the EvanioideaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 4 2010Enrique PEÑALVER Abstract: One new genus and five new species of the family Evaniidae are described from the Early Cretaceous (Albian) Spanish amber of Peñacerrada-I (Province of Burgos), San Just and Arroyo de la Pascueta (both in the Province of Teruel): Cretevania alonsoi sp. nov., C. montoyai sp. nov., C. alcalai sp. no v., C. rubusensis sp. nov., and Iberoevania roblesi gen. and sp. nov. Taxonomic changes include Cretevania pristina (Zhang and Zhang, 2000) comb. nov., C. exquisita (Zhang, Rasnitsyn, Wang and Zhang, 2007) comb. nov., C. vesca (Zhang, Rasnitsyn, Wang and Zhang, 2007) comb. nov., and C. cyrtocerca (Deans, 2004) comb. nov., as a result of the reinterpretation of the genera Procretevania and Eovernevania. The new well preserved specimens of the genus Cretevania, together with the characters shown by the type specimens of the synonymized genera, give new information about their anatomical characters of taxonomical importance, and the genus Cretevania Rasnitsyn, 1975 is re-diagnosed. The holotypes of the Russian species in amber have been revised. A cladistic analysis of fossil and extant groups of the superfamily Evanioidea is included. Cretevania had a wide palaeogeographic distribution, with the highest diversity known from Spain. The 13 known Cretevania species show a high interspecific variation mainly in wing characteristics, and a wide range of body and wing size. [source] | |||||||||||||