69 resultados para Geographic distribuition
Resumo:
The specific identity of endosymbiotic dinoflagellates (Symbiodinium spp.) from most zooxanthellate corals is unknown. In a survey of symbiotic cnidarians from the southern Great Barrier Reef (GBR), 23 symbiont types were identified from 86 host species representing 40 genera. A majority (>85%) of these symbionts belong to a single phylogenetic clade or subgenus (C) composed of closely related (as assessed by sequence data from the internal transcribed spacer region and the ribosomal large subunit gene), yet ecologically and physiologically distinct, types. A few prevalent symbiont types, or generalists, dominate the coral community of the southern GBR, whereas many rare and/or specific symbionts, or specialists, are found uniquely within certain host taxa. The comparison of symbiont diversity between southern GBR and Caribbean reefs shows an inverse relationship between coral diversity and symbiont diversity, perhaps as a consequence of more-rapid diversification of Caribbean symbionts. Among clade C types, generalists C1 and C3 are common to both Caribbean and southern GBR symbiont assemblages, whereas the rest are regionally endemic. Possibly because of environmental changes in the Caribbean after geographic isolation through the Quaternary period, a high proportion of Caribbean fauna associate with symbiont taxa from two other distantly related Symbiodinium clades (A and B) that rarely occur in Pacific hosts. The resilience of Porites spp. and the resistance of Montipora digitata to thermal stress and bleaching are partially explained by their association with a thermally tolerant symbiont type, whereas the indiscriminant widespread bleaching and death among certain Pacific corals, during El Nino Southern Oscillation events, are influenced by associations with symbionts possessing higher sensitivity to thermal stress.
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The Australian Soil Resources Information System (ASRIS) database compiles the best publicly available information available across Commonwealth, State, and Territory agencies into a national database of soil profile data, digital soil and land resources maps, and climate, terrain, and lithology datasets. These datasets are described in detail in this paper. Most datasets are thematic grids that cover the intensively used agricultural zones in Australia.
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The role of temperature and rainfall during seed development in modulating subsequent seed dormancy status was studied for Lolium rigidum Gaud. (annual ryegrass). Climatic parameters relating to geographic origin were compared with annual ryegrass seed dormancy characteristics for seeds collected from 12 sites across the southern Western Australian cropping region. Seed germination was tested soon after collection and periodically during subsequent after-ripening. Temperature in the year of seed development and long-term rainfall patterns showed correlations with aspects of seed dormancy, particularly the proportion of seeds remaining dormant following 5 months of after-ripening. Consequently, for one population the temperature (warm/cool) and water supply (adequate/reduced) during seed development were manipulated to investigate the role of maternal environment in the quantity and dormancy characteristics of seeds produced. Seeds from plants grown at warm temperatures were fewer in number, weighed less, and were less dormant than those from plants grown at cool temperature. Seeds that developed under both cool temperature and reduced moisture conditions lost dormancy faster than seeds from well-watered plants. Seed maturation environment, particularly temperature, can have a significant effect on annual ryegrass seed numbers and seed dormancy characteristics.
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The diversity and community structures of symbiotic dinoflagellates are described from reef invertebrates in southern and central provinces of the Great Barrier Reef (GBR), Australia, and Zamami Island, Okinawa, Japan. The symbiont assemblages from region to region were dominated by Clade C Symbiodinium spp. and consisted of numerous host-specific and/or rare types (specialists), and several types common to many hosts (generalists). Prevalence in the host community among certain host-generalist symbionts differed between inshore and offshore environments, across latitudinal (central versus southern GBR) gradients, and over wide geographic ranges (GBR versus Okinawa). One particular symbiont (C3h) from the GBR had a dramatic shift in dominance. Its prevalence ranged from being extremely rare, or absent on high-latitude reefs to dominating the scleractinian diversity on a mid-latitude inshore reef. These changes occurred among coral fauna whose larvae must acquire symbionts from environmental sources (horizontal symbiont acquisition). Such differences did not occur among 'vertical transmitters' such as Porites spp., Montipora spp. and pocilloporids (corals that directly transmit symbionts to their offspring) or among those hosts displaying 'horizontal acquisition', but that associate with specific symbionts. Most host-specialized types were found to be characteristic of a particular geographic region (i.e. Okinawa versus Central GBR versus Southern GBR). The mode of symbiont acquisition may play an important role in how symbiont composition may shift in west Pacific host communities in response to climate change. There is no indication that recent episodes of mass bleaching have provoked changes in host-symbiont combinations from the central GBR.
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Genetic population structure in the catadromous Australian bass Macquaria novemaculeata was investigated using samples from four locations spanning 600 km along the eastern Australian coastline. Both allozymes and mtDNA control region sequences were examined. Population subdivision estimates based on allozymes revealed low levels of population structuring (G(st)=0.043, P<0.05). However, mtDNA indicated moderate levels of geographic population structure (G(st)=0.146, P<0.01). Phylogenetic analysis of mtDNA control region sequences (mean sequence divergence 1.9%) indicated little phylogeographic structuring. Results suggested that genotypic variation within each river population, while bring affected primarily by genetic drift, was also prevented from more significant divergence by homogenizing levels of gene flow-synonymous with a one-dimensional stepping-stone model of population structure. The catadromous life history of Macquaria novemaculeata was considered to br influential on the pattern of population structure displayed. Results were compared to the few population genetic studies involving catadromous fishes, indicating that catadromy alone is unlikely to be a good predictor of population structure. A more comprehensive suite of biological characteristics than simple life-history traits must be considered fully to allow reliable predictive models of population structure to be formulated. (C) 1997 The Fisheries Society of the British Isles.
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Geographical information systems (GIS) coupled to 3D visualisation technology is an emerging tool for urban planning and landscape design applications. The utility of 3D GIS for realistically visualising the built environment and proposed development scenarios is much advocated in the literature. Planners assess the merits of proposed changes using visual impact assessment (VIA). We have used Arcview GIS and visualisation software: called PolyTRIM from the University of Toronto, Centre for Landscape Research (CLR) to create a 3D scene for the entrance to a University campus. The paper investigates the thesis that to facilitate VIA in planning and design requires not only visualisation, but also a structured evaluation technique (Delphi) to arbitrate the decision-making process. (C) 2001 Elsevier Science B.V. All rights reserved.
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Until recently, West Nile (WN) and Kunjin (KUN) viruses were classified as distinct types in the Flavivirus genus. However, genetic and antigenic studies on isolates of these two viruses indicate that the relationship between them is more complex. To better define this relationship, we performed sequence analyses on 32 isolates of KUN virus and 28 isolates of WN virus from different geographic areas, including a WN isolate from the recent outbreak in New York. Sequence comparisons showed that the KUN virus isolates from Australia were tightly grouped but that the WN virus isolates exhibited substantial divergence and could be differentiated into four district groups. KUN virus isolates from Australia were antigenically homologous and distinct from the WN isolates and a Malaysian KUN virus. Our results suggest that KUN and WN viruses comprise a group of closely related viruses that can be differentiated into subgroups on the basis of genetic and antigenic analyses.
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Benedenia Diesing, 1858, a genus of capsalid (benedeniine) monogeneans, is redefined. The generic diagnosis is amended to include: the path of tendons in the haptor from extrinsic muscles in the body; presence and form of the marginal valve; a penis occupying a penis canal with weakly muscular wall; a weakly muscular accessory gland reservoir proximal to the penis and enclosed by a proximal extension of the wall of the penis canal; male and female genital apertures usually common, rarely separate; vagina with pore usually close to the common genital pore but may open in mid body between the germarium and the common genital pore, or anterior to the common genital pore. A conservative approach is adopted and the generic diagnosis is clarified and broadened to accommodate species that display some variation in reproductive anatomy, especially of the female system. We argue against potential alternative actions such as defining Benedenia strictly to contain species with separate male and female genital apertures and against recognition of a separate genus, Tareenia Hussey, 1986, for species with a vaginal pore anterior to the common genital pore. Under our conception, Benedenia comprises 21 species: B. sciaenae (van Beneden, 1856) Odhner, 1905 (type species); B. acanthopagri (Hussey, 1986) comb. nov.; B. anticavaginata Byrnes, 1986; B. bodiani Yamaguti, 1968; B. elongata (Yamaguti, 1968) Egorova, 1997; B. epinepheli (Yamaguti, 1937) Meserve, 1938; B. hawaiiensis Yamaguti, 1968; B. hendorffi(von Linstow, 1889) Odhner, 1905; B. hoshinai Ogawa, 1984; B. innobilitata Burhnheim Gomes and Varela, 1973: B. jaliscana Bravo-Hollis, 1952; B. lolo Yamaguti, 1968; B. lutjani Whittington and Kearn, 1993: B. monticellii (Parona and Perugia, 1895) Johnston, 1929; B. ovata (Goto, 1894) Johnston. 1929: B. pompatica Burhnheim, Gomes and Varela, 1973; B. rohdei Whittington, Kearn and Beverley-Burton, 1994; B. scari Yamaguti, 1968; B. sekii (Yamaguti, 1937) Meserve, 1938; B, seriolae (Yamaguti, 1934) Meserve, 1938; and B. synagris Yamaguti, 1953. The type species, B. sciaenae, is redescribed based on new material from Australia. No types for this taxon were designated and we have assigned a series of voucher specimens. Tareenia acanthopagri Hussey, 1986 becomes B. acanthopagri (Hussey, 1986) comb. nov. and T. anticavaginata (Byrnes, 1986) Egorova, 1997 and T. lutjani (Whittington and Kearn, 1993) Egorova, 1997 are returned to Benedenia as B. anticavaginata and B. lutjani Benedenia akaisaki Iwata, 1990 is considered a synonym of B. ovata and B. kintoki Iwata, 1990 is considered a synonym of B. elongata. Two species, B, madai Ishii and Sawada, 1938 and B. pagrosomi Ishii and Sawada, 1938, are considered species inquirendae. Based on the redefinition of Benedenia, the diagnosis for the Benedeniinae is amended. Tareenia is synonymized with Benedenia but Menziesia Gibson, 1976 is recognized and its generic diagnosis amended to include: anterior attachment organs tending to form a 'hooded' appearance; prominent anterior gland cells between the pharynx and the anterior margin of the body: long penis, tapering proximally, occupying a penis canal with weakly muscular wall: penis canal and penis describe a sigmoid; accessory gland reservoir dorsal and alongside, or posterior and lateral to, proximal end of the penis and enclosed by a proximal extension of the wall of the penis canal. Under this conception. Menziesia comprises: M. noblei (Menzies. 1946) Gibson, 1976 (type species); M. malaboni (Velasquez. 1982) comb. nov.: M. merinthe (Yamaguti, 1968) Gibson. 1976: M. ovalis (Yamaguti, 1968) Gibson, 1976: and M. sebastodis (Yamaguti, 1934) comb, nov. A key to valid species of Benedenia and Menziesia is provided and a list is presented of published records of undescribed or unattributed species of Benedenia. Some protocols are suggested for preparation of benedeniine material to enhance future taxonomic studies and comparisons. The host-specificity and geographic distribution of species in these revised genera are discussed. The composition of the Capsalidae is discussed and some difficulties in defining and distinguishing between its different subfamilies are considered.
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Although viperlike in appearance and habit, death adders belong to the Elapidae family of snakes. Systemic envenomation represents a serious medical problem with antivenom, which is raised against Acanthophis antarcticus venom, representing the primary treatment. This study focused on the major Acanthophis variants from Australia and islands in the Indo-Pacific region. Venoms were profiled using liquid chromatography-mass spectrometry, and analyzed for in vitro neurotoxicity (0.3-10 mug/ml), as well as the effectiveness of antivenom. (1-5 units/ml; 10 min prior to the addition of 10 mug/ml venom). The following death adder venoms were examined: A. antarcticus (from separate populations in New South Wales, Queensland, South Australia, and Western Australia), A. hawkei, A. praelongus, A. pyrrhus, A. rugosus, A. wellsi, and venom from an unnamed species from the Indonesian island of Seram. All venoms abolished indirect twitches of the chick isolated biventer cervicis nerve-muscle preparation in a dose-dependent manner. In addition, all venoms blocked responses to exogenous acetylcholine (1 m-M) and carbachol (20 muM), but not KCl (40 mM), suggesting postsynaptic neurotoxicity. Death adder antivenom (1 unit/ml) prevented the neurotoxic effects of A. pyrrhus, A. praelongus, and A. hawkei venoms, although it was markedly less effective against venoms from A. antarcticus (NSW, SA, WA), A. rugosus, A. wellsi, and A. sp. Scram. However, at 5 units/ml, antivenom was effective against all venoms tested. Death adder venoms, including those from A. antarcticus geographic variants, differed not only in their venom composition but also in their neurotoxic activity and susceptibility to antivenom. For the first time toxicological aspects of A. hawkei, A. wellsi, A. rugosus, and A. sp. Seram venoms were studied. (C) 2001 Academic Press.
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Regional planners, policy makers and policing agencies all recognize the importance of better understanding the dynamics of crime. Theoretical and application-oriented approaches which provide insights into why and where crimes take place are much sought after. Geographic information systems and spatial analysis techniques, in particular, are proving to be essential or studying criminal activity. However, the capabilities of these quantitative methods continue to evolve. This paper explores the use of geographic information systems and spatial analysis approaches for examining crime occurrence in Brisbane, Australia. The analysis highlights novel capabilities for the analysis of crime in urban regions.
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We inferred the phylogeny of 33 species of ticks from the subfamilies Rhipicephalinae and Hyalomminae from analyses of nuclear and mitochondrial DNA and morphology. We used nucleotide sequences from 12S rRNA, cytochrome c oxidase I, internal transcribed spacer 2 of the nuclear rRNA, and 18S rRNA. Nucleotide sequences and morphology were analyzed separately and together in a total-evidence analysis. Analyses of the five partitions together (3303 characters) gave the best-resolved and the best-supported hypothesis so far for the phylogeny of ticks in the Rhipicephalinae and Hyalomminae, despite the fact that some partitions did not have data for some taxa. However, most of the hidden conflict (lower support in the total-evidence analyses compared to that in the individual analyses) was found in those partitions that had taxa without data. The partitions with complete taxonomic sampling had more hidden support (higher support in the total-evidence analyses compared to that in the separate-partition analyses) than hidden conflict. Mapping of geographic origins of ticks onto our phylogeny indicates an African origin for the Rhipicephalinae sensu lato (i.e., including Hyalomma spp.), the Rhipicephalus-Boophilus lineage, the Dermacentor-Anocentor lineage, and the Rhipicephalus-Booophilus-Nosomma-Hyalomma-Rhipicentor lineage. The Nosomma-Hyalomma lineage appears to have evolved in Asia. Our total-evidence phylogeny indicates that (i) the genus Rhipicephalus is paraphyletic with respect to the genus Boophilus, (ii) the genus Dermacentor is paraphyletic with respect to the genus Anocentor, and (iii) some subgenera of the genera Hyalomma and Rhipicephalus are paraphyletic with respect to other subgenera in these genera. Study of the Rhipicephalinae and Hyalomminae over the last 7 years has shown that analyses of individual datasets (e.g., one gene or morphology) seldom resolve many phylogenetic relationships, but analyses of more than one dataset can generate well-resolved phylogenies for these ticks. (C) 2001 Academic Press.
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The taxonomic relationship between two toothed South African river crabs, Potamonautes warreni and P. unispinus, is unclear. The problem stems from the widespread variation in carapace dentition patterns amongst P. warreni individuals over its biogeographic range, where single toothed individuals may appear similar in carapace morphology to P. unispinus. Ten populations of P. warreni and 18 populations of P. unispinus were collected and the morphometric and genetic differentiation between the two taxa quantified. Patterns of morphometric and genetic variation were examined using multivariate statistics and protein gel electrophoresis, respectively. Principal component analyses of carapace characters showed that the two species are morphologically indistinguishable. However, discriminate functions analyses and additional statistical results corroborate the morphological distinction between the two taxa. Allozyme electrophoresis of 17 protein coding loci, indicated a close genetic similarity between the two species (I = 0.92). A fixed allelic difference at one locus (LT-2) and extensive genetic variability at another locus (PGM-1) indicate that two gene pools are present and that the two taxa are genetically isolated. Intraspecific genetic I values for both species were > 0.97 and indicated no apparent genetic structuring on a micro or macro-geographic scale. The variation in carapace dentition among P. warreni populations possesses no genetic basis and may possibly toe the product of ecogenesis. The value of dentition patterns in the systematics of river crabs is discussed. Dentition patterns among river crab species appear to be conserved and reliable as species specific diagnostic markers, but should ideally be used in combination with other morphological data sets and genetic evidence.
Resumo:
The scleractinian coral species, Seriatopora hystrix and Acropora longicyathus, are widely distributed throughout the latitudinal range of the tropical west Pacific. These 2 coral species live in a mutually beneficial relation with symbiotic dinoflagellates (zooxanthellae), which are passed to their progeny by vertical transmission (zooxanthellate eggs or larvae) and horizontal transmission (eggs or larvae that acquire symbionts from the environment), respectively. For S. hystrix, vertical transmission might create biogeographically isolated and genetically differentiated symbiont populations because the extent of its larval migration is known to be limited. On the other hand, horizontal transmission in corals such as A. longicyathus may result in genetically connected symbiont populations, especially if its zooxanthellae taxa are widely distributed. To examine these hypotheses, symbionts were collected from colonies of S. hystrix and A. longicyathus living in the Great Barrier Reef (Australia), South China Sea (Malaysia) and East China Sea (Ryukyus Archipelago, Japan), and were examined using restriction fragment length polymorphism and sequence analysis of large and small subunit rRNA genes. Phylogenetic analysis assigned the symbionts to 1 of 3 taxonomically distinct groups, known as clades. Symbionts from Australian and Japanese S. hystrix were placed in Clade C, and Malaysian S. hystrix symbionts in the newly described Clade D. Seven of 11 Australian and all Japanese and Malaysian colonies of A. longicyathus had symbiotic dinoflagellates that also grouped with Clade C, but symbionts from the remaining Australian colonies of A. longicyathus grouped with Clade A. Analysis of molecular variance of Clade C symbionts found significant genetic variation in 1 or more geographic groups (69.8%) and to a lesser extent among populations within geographic regions (13.6%). All populations of Clade C symbionts from S. hystrix were genetically differentiated according to geographic region. Although Clade C symbionts of A. longicyathus from Japan resolved into a distinct geographic group, those from Australia and Malaysia did not and were genetically connected. We propose that these patterns of genetic connectivity correlate with differences in the dispersal range of the coral or symbiont propagules and are associated with their respective modes of symbiont transmission.
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Several small isolates of rainforest situated on the central eastern coast of Australia are home to a rich herpetofauna, including four endemic species of leaftail geckos (Phyllurus spp.) and two skinks (Eulamprus spp.). To examine the extent and geographic pattern of historical subdivision among isolates, we assayed mtDNA variation in two species endemic to rainforests of this region (Phyllurus ossa and Eulamprus amplus) and, for comparison, a more widespread and less specialised lizard, Carlia rhomboidalis. There is a clear genetic signature of historical changes in population size and distribution in P. ossa that is consistent with Pleistocene (or earlier) rainforest contraction and subsequent expansion. Although more pronounced in the gecko, phylogeographic structure was congruent between E. amplus and P. ossa. In contrast to the saxicolous, rainforest-restricted P. ossa and E. amplus, the rainforest-generalist species, C. rhomboidalis, does not display strong geographic population structure. The differences in genetic population structure exhibited by the three species are consistent with species-specific differences in ecology.