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Murray K.A.,University of Queensland | Rosauer D.,University of New South Wales | Rosauer D.,Center for Plant Biodiversity Research | McCallum H.,Griffith University | Skerratt L.F.,James Cook University
Proceedings of the Royal Society B: Biological Sciences

In studies of extinction risk, it is often insufficient to conclude that species with narrow ranges or small clutch sizes require prioritized protection. To improve conservation outcomes, we also need to know which threats interact with these traits to endanger some species but not others. In this study, we integrated the spatial patterns of key threats to Australian amphibians with species' ecological/life-history traits to both predict declining species and identify their likely threats. In addition to confirming the importance of previously identified traits (e.g. narrow range size), we find that extrinsic threats (primarily the disease chytridiomycosis and invasive mosquitofish) are equally important and interact with intrinsic traits (primarily ecological group) to create guild-specific pathways to decline in our model system. Integrating the spatial patterns of extrinsic threats in extinction risk analyses will improve our ability to detect and manage endangered species in the future, particularly where data deficiency is a problem. © 2011 The Royal Society. Source

Murray K.A.,University of Queensland | Retallick R.W.R.,GHD Pty Ltd | Puschendorf R.,James Cook University | Skerratt L.F.,James Cook University | And 6 more authors.
Journal of Applied Ecology

Correlative species distribution models can be used to produce spatially explicit estimates of environmental suitability for organisms. This process can provide meaningful information for a range of purposes (e.g. estimating a species' current or future distribution, estimating dispersal limits, predicting occupancy for conservation planning) but, like all statistical exercises, is subject to numerous assumptions and can be influenced by several sources of potential bias. 2. In this issue of Journal of Applied Ecology, we (Murray 2011) employ a correlative species distribution model for infection with the pathogen Batrachochytrium dendrobatidis (Bd), cause of amphibian chytridiomycosis, to derive useful information for the immediate management and research of this pathogen in Australia. Also in this issue, Rohr, Halstead & Raffel (2011) comment on some of the potential limitations of our approach and the value of our results in practice. 3. Synthesis and applications. Here we show that while a focus on mechanisms of dispersal and transmission among hosts, as advocated in both studies, is an important objective for modelling Bd distribution under climate change or at invasion fronts, correlative models can be of immediate value for their ability to generate a baseline hypothesis about the current potential distribution of this lethal pathogen and for efficiently identifying gaps in current knowledge. As demonstrated in our paper, this should help improve the immediate allocation of limited research and management resources for future surveillance efforts and proactive species conservation. © 2010 The Authors. Journal of Applied Ecology © 2010 British Ecological Society. Source

Godfree R.,CSIRO | Lepschi B.,Center for Plant Biodiversity Research | Reside A.,CSIRO | Bolger T.,EcoLao Consultants | And 3 more authors.
Global Change Biology

It is argued that the inclusion of spatially heterogeneous environments in biodiversity reserves will be an effective means of encouraging ecosystem resilience and plant community conservation under climate change. However, the resilience and resistance of plant populations to global change, the specific life-history traits involved and the spatial scale at which environmentally driven demographic variation is expressed remains largely unknown for most plant groups. Here we address these questions by reporting an empirical investigation into the impacts of an unprecedented 3-year drought on the demography, population growth rates (γ) and biogeographical distribution of core populations of the perennial grassland species Austrostipa aristiglumis in semiarid Australia. We use life-history analysis and periodic matrix population models to specifically test the hypothesis that patch- and habitat-scale variation in vital life-history parameters result in spatial differences in the resilience and resistance of A. aristiglumis populations to extreme drought. We show that the development of critical soil water deficits during drought resulted in collapse of adult A. aristiglumis populations (γ«1), rapid interhabitat phytosociological change and overall contraction towards mesic refugia where populations were both more resistant and resilient to perturbation. Population models, combined with climatic niche analysis, suggest that, even in core areas, a significant reduction in size and habitat range of A. aristiglumis populations is likely under climate change expected this century. Remarkably, however, we show that even minor topographic variation (0.2-3m) can generate significant variation in demographic parameters that confer population-level resilience and resistance to drought. Our findings support the hypothesis that extreme climatic events have the capacity to induce rapid, landscape-level shifts in core plant populations, but that the protection of topographically heterogeneous environments, even at small spatial scales, may play a key role in conserving biodiversity under climate change in the coming century. © 2010 Blackwell Publishing Ltd. Source

Murray K.A.,University of Queensland | Retallick R.W.R.,GHD Pty Ltd | Puschendorf R.,James Cook University | Skerratt L.F.,James Cook University | And 6 more authors.
Journal of Applied Ecology

Emerging infectious diseases can have serious consequences for wildlife populations, ecosystem structure and biodiversity. Predicting the spatial patterns and potential impacts of diseases in free-ranging wildlife are therefore important for planning, prioritizing and implementing research and management actions. 2.We developed spatial models of environmental suitability (ES) for infection with the pathogen Batrachochytrium dendrobatidis, which causes the most significant disease affecting vertebrate biodiversity on record, amphibian chytridiomycosis. We applied relatively newly developed methods for modelling ES (Maxent) to the first comprehensive, continent-wide data base (comprising >10000 observations) on the occurrence of infection with this pathogen and employed novel methodologies to deal with common but rarely addressed sources of model uncertainty. 3.We used ES to (i) predict the minimum potential geographic distribution of infection with B. dendrobatidis in Australia and (ii) test the hypothesis that ES for B. dendrobatidis should help explain patterns of amphibian decline given its theoretical and empirical link with organism abundance (intensity of infection), a known determinant of disease severity. 4.We show that (i) infection with B. dendrobatidis has probably reached its broad geographic limits in Australia under current climatic conditions but that smaller areas of invasion potential remain, (ii) areas of high predicted ES for B. dendrobatidis accurately reflect areas where population declines due to severe chytridiomycosis have occurred and (iii) that a host-specific metric of ES for B. dendrobatidis (ES for Bdspecies) is the strongest predictor of decline in Australian amphibians at a continental scale yet discovered. 5.Synthesis and applications. Our results provide quantitative information that helps to explain both the spatial distribution and potential effects (risk) of amphibian infection with B. dendrobatidis at the population level. Given scarce conservation resources, our results can be used immediately in Australia and our methods applied elsewhere to prioritize species, regions and actions in the struggle to limit further biodiversity loss. © 2010 The Authors. Journal of Applied Ecology © 2010 British Ecological Society. Source

Villarreal J.C.,University of Connecticut | Goffinet B.,University of Connecticut | Duff R.J.,University of Akron | Cargill D.C.,Center for Plant Biodiversity Research

Recent reconstruction of the phylogenetic relationships of hornworts has revealed novel hypotheses of unique common ancestries. The genus Megaceros, for example, was shown to be polyphyletic with New World species nested within Nothoceros. Here we present a sampling of most widely recognized species of both genera to provide a phylogenetic delimitation of Nothoceros and Megaceros based on the genes rbcL and nad5. The unique ancestry shared by Nothoceros and the New World species of Megaceros is confirmed. This clade, except for the New Zealand endemic N. giganteus is restricted to the American continent. The genus Megaceros is redefined to comprise only Asian and Australasian species. The three widely accepted American species of Megaceros, M. aenigmaticus, M. fuegiensis and M. vincentianus are transferred here to Nothoceros. The lack of defining morphological characters for Nothoceros along with its morphological diversity highlights the need for further taxonomic, morphological and ultrastructural studies of the genus. © 2010 by The American Bryological and Lichenological Society, Inc. Source

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