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Tropical Australia (tropical + australia)
Selected AbstractsHealthy Country, Healthy People: Policy Implications of Links between Indigenous Human Health and Environmental Condition in Tropical AustraliaAUSTRALIAN JOURNAL OF PUBLIC ADMINISTRATION, Issue 1 2009Stephen T. Garnett Investment in programs that help Indigenous people undertake work maintaining the environmental health of their country has benefits for the environment as well as the physical, mental and cultural health of the Indigenous people involved. For health these findings have direct implications for some national health policies, service provision to homelands, health promotion and Indigenous health research. There are also direct implications for environmental investment in northern Australia and the design and regulation of markets in resource entitlements. Indirectly the findings should be important for economic, employment and education policies as well as those promoting social harmony. Given the range of benefits there is a strong argument for cross-agency investment in working on country by Indigenous people. [source] A new bacteriophage, VHML, isolated from a toxin-producing strain of Vibrio harveyi in tropical AustraliaJOURNAL OF APPLIED MICROBIOLOGY, Issue 4 2000H.J. Oakey Some strains of Vibrio harveyi are known to be pathogenic for fish and many invertebrates including crustaceans. Despite their importance, their modes of virulence have yet to be fully elucidated. Here, we present a previously unreported bacteriophage extracted from a toxin-producing strain of V. harveyi isolated from moribund prawn larvae in tropical Australia. Classification into the family Myoviridae was based upon morphological characteristics (an icosahedral head, a neck/collar region and a sheathed rigid tail) and nucleic acid characteristics (double-stranded linear DNA). We have termed the bacteriophage VHML (Vibrio Harveyi Myovirus Like). VHML is a temperate bacteriophage that has a narrow host range and shows an apparent preference for V. harveyi above other vibrios (63 Vibrio isolates tested) and other genera (10 other genera were tested). The conventional methods for phage concentration and extraction of nucleic acids from phage particles were not efficient and the alternative methods that were used are discussed. [source] Population genetic structure, gene flow and sex-biased dispersal in frillneck lizards (Chlamydosaurus kingii)MOLECULAR ECOLOGY, Issue 15 2008BEATA UJVARI Abstract By using both mitochondrial and nuclear multiloci markers, we explored population genetic structure, gene flow and sex-specific dispersal of frillneck lizards (Chlamydosaurus kingii) sampled at three locations, separated by 10 to 50 km, in a homogenous savannah woodland in tropical Australia. Apart from a recombinant lizard, the mitochondrial analyses revealed two nonoverlapping haplotypes/populations, while the nuclear markers showed that the frillneck lizards represented three separate clusters/populations. Due to the small population size of the mtDNA, fixation may occur via founder effects and/or drift. We therefore suggest that either of these two processes, or a combination of the two, are the most likely causes of the discordant results obtained from the mitochondrial and the nuclear markers. In contrast to the nonoverlapping mitochondrial haplotypes, in 12 out of 74 lizards, mixed nuclear genotypes were observed, hence revealing a limited nuclear gene flow. Although gene flow should ultimately result in a blending of the populations, we propose that the distinct nuclear population structure is maintained by frequent fires resulting in local bottlenecks, and concomitant spatial separation of the frillneck lizard populations. Limited mark,recapture data and the difference in distribution of the mitochondrial and nuclear markers suggest that the mixed nuclear genotypes were caused by juvenile male-biased dispersal. [source] Vulnerability of an Australian anuran tadpole assemblage to the toxic eggs of the invasive cane toad (Bufo marinus)AUSTRAL ECOLOGY, Issue 2 2010MICHAEL R. CROSSLAND Abstract The invasion of cane toads (Bufo marinus) across tropical Australia has fatally poisoned many native predators; the most frequent victims may be tadpoles of native frogs, which die when they consume the toxic eggs of the toads. Field studies have documented high and species-specific mortality of tadpoles following toad spawning. To clarify the determinants of tadpole vulnerability, we conducted 1593 laboratory trials in which single tadpoles were exposed to 10 toad eggs, either with or without an alternative food source (lettuce). At least some tadpoles within all 15 species tested consumed toad eggs. Interspecific variance in survival rates (from 0 to >70%) was driven by feeding responses not by physiological tolerance to toxins: almost all native tadpoles that consumed eggs died rapidly. Tadpole mortality was decreased by the presence of an alternative food source in four species, increased in two species, and not affected in seven species. In three of four taxa where we tested both small (early-stage) and large (late-stage) tadpoles, both mean survival rates and the effects of alternative food on survival shifted with tadpole body size. Trials with one species (Limnodynastes convexiusculus) showed no significant inter-clutch variation in feeding responses or tolerance to toxins. Overall, our data show that cane toad eggs are highly toxic to native anuran tadpoles, but that whether or not a tadpole is killed by encountering toad eggs depends upon a complex interaction between the native anuran's species, its body size, and whether or not alternative food was present. In nature, larval vulnerability also depends upon the seasonal timing and location of spawning events, and habitat selection and foraging patterns of the tadpoles. Our results highlight the complexity of vulnerability determinants, and identify ecological factors (rather than physiology or feeding behaviour) as the primary determinants of cane toad impact on native tadpoles. [source] Structure and species richness in wetland continua on sandy soils in subtropical and tropical AustraliaAUSTRAL ECOLOGY, Issue 7 2009RAYMOND L. SPECHT Abstract Net photosynthetic fixation of wetland plant communities is confined to the period of the year when the surface soil is not waterlogged and is thus well aerated. In the open-structured vegetation continuum across freshwater wetlands on sandy soils in subtropical and tropical Australia, the sum of the foliage projective covers (FPCs) of the overstorey and understorey strata remains constant, while that of the overstorey decreases to zero as seasonal waterlogging (and anaerobic conditions) in the surface root systems increases. Density and height of the overstorey trees , of only one or two species , and species richness (number of species per hectare) in the understorey decreases along this waterlogging gradient. Melaleuca paperbark trees, possessing surface roots with cortical aerenchyma, may form a closed-forest at the edge of the wetland continuum wherever there is a continuous flow of aerated water. As global warming progresses, an increase in air temperature in the atmosphere flowing over and through the wetland continuum during the short period of annual foliage-growth will affect the combined FPCs of overstorey and understorey strata, as well as the leaf-specific weights of all leaves throughout the plant community. With a reduction in net photosynthetic fixation, species richness of the plant community will slowly decline. [source] Spawning site selection by feral cane toads (Bufo marinus) at an invasion front in tropical AustraliaAUSTRAL ECOLOGY, Issue 5 2006MATTIAS HAGMAN Abstract Spawning sites are a critical and often scarce resource for aquatic-breeding amphibians, including invasive species such as the cane toad (Bufo marinus). If toads select spawning sites based on habitat characteristics, we can potentially manipulate those characteristics to either enhance or reduce their suitability as breeding sites. We surveyed 25 spawning sites used by cane toads, and 25 adjacent unused sites, in an area of tropical Australia recently invaded by these feral anurans. Water chemistry (pH, conductivity, salinity, turbidity) was virtually identical between the two sets of waterbodies, but habitat characteristics were very different. Toads selectively oviposited in shallow pools with gradual rather than steep slopes, and with open (unvegetated) gradually sloping muddy banks. They avoided flowing water, and pools with steep surrounds. In these respects, cane toads broadly resemble previously studied toad species in other parts of the world, as well as conspecifics within their natural range in South America. [source] The Thrips orientalis group from South-east Asia and Australia: some species identities and relationships (Thysanoptera, Thripidae)AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 4 2005Laurence A Mound Abstract, A thrips associated in Thailand with the flowers of Paederia foetida, a rubiaceous weed in Florida that is a threat to Australia, is here recognised as Thrips morindae Priesner, a species previously considered a synonym of T. javanicus Priesner. Systematic relationships of these species with others in South-east Asia and the Australasian region are discussed. Two new species-groups are designated: the T. obscuratus group of six species from New Zealand and New Caledonia, and the T. orientalis group of 12 South-east Asian species that are associated with scented white flowers such as Gardenia. Four species of this second group are recorded from tropical Australia. [source] The aquatic thrips Organothrips indicus Bhatti (Thysanoptera: Thripidae) in Queensland, and a new species, O. wrighti, from tropical AustraliaAUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2000Laurence A Mound Abstract The genus Organothrips includes the only fully aquatic thrips, the two previously known species breeding under water in the surface mucous of several unrelated monocotyledonous plants. Organothrips indicus Bhatti is recorded in Australia for the first time, breeding on water hyacinth (Eichhornia crassipes) in a greenhouse near Brisbane. Structural variation within this population is discussed, and character states considered for distinguishing this species from the Pacific taro thrips, O. bianchii Hood. A new species, Organothrips wrighti, is described from Melville Island, Northern Territory and from Cape Tribulation, Queensland. This species has fully macropterous males and is probably not aquatic. The studies on Eichhornia also gave rise to two new distribution records; Salpingothrips aimotofus Kudo is newly recorded from Australia, and the Northern Hemisphere pest thripid Echinothrips americanus Morgan is newly recorded from Thailand. [source] Effects of nest temperature and moisture on phenotypic traits of hatchling snakes (Tropidonophis mairii, Colubridae) from tropical AustraliaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2006GREGORY P. BROWN Previous research on developmentally plastic responses by reptile embryos has paid relatively little attention to tropical species, or to possible interactions between the effects of thermal and hydric regimes. In the present study, eggs of keelback snakes (Tropidonophis mairii), from a tropical area with strong temporal and spatial variation in soil temperatures and moisture levels, were incubated. The phenotypic traits of hatchling snakes (body size, shape, muscular strength) were affected by moisture content of the incubation medium (vermiculite plus 100% vs. 50% water by mass), by mean incubation temperatures (25.7 vs. 27.9 °C) and by diel thermal variation (diel range 6.0 vs. 8.4 °C). Interactions between these factors were negligible. Cooler, more thermostable, moister conditions resulted in larger offspring, a trait under strong selection in this population. Thermal and hydric conditions covary in potential nest-sites (e.g. deeper nests are more thermostable as well as moister). This covariation may influence the evolution of reaction norms for embryogenesis. For example, if moister nests enhance offspring fitness and are cooler, then selection will favour the ability to develop in cool as well as moist conditions. Thus, the evolution of optimal incubation conditions with respect to one variable (e.g. temperature) may be driven by patterns of association with another variable (e.g. soil moisture) among natural nest-sites. Perhaps for this reason, the thermal optimum for incubation is surprisingly low in this tropical species. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 159,168. [source] Transformative Knowledge Transfer Through Empowering and Paying Community ResearchersBIOTROPICA, Issue 5 2009Stephen T. Garnett ABSTRACT Environmental research is often conducted independently of the community in which the environment is situated, with transfer of results into policy and on-ground action occurring independently of the community's interests or aspirations. Increasingly the need for greater community involvement in the research process has been recognized. For community members, however, such engagement usually involves trade-offs. While it is often assumed that community members should participate voluntarily because they will gain from the research, any benefits from knowledge, understanding and a capacity to influence the research have to be offset against time and potential loss of unremunerated intellectual property. We argue, using case studies from tropical Australia and Africa, that a more effective means of engagement and knowledge transfer is training and remuneration of community members as coresearchers. This engagement is much more than payment for labor,it is investment in local intellectual property and requires researcher humility, power-sharing and recognition that access to research funding provides no moral or intellectual authority. Further, we argue that, for effective adoption of research results, community members need to be part of negotiated agreements on the initial nature of the research to ensure it answers questions of genuine local relevance and that local researchers have the capacity to place locally conducted research into a wider context. We argue that immediate rewards for involvement not only secure engagement but, where appropriate, are likely to lead to effective implementation of research results, enhanced local capacity and greater equity in intellectual power-sharing. [source] | ||||||||||