In recent decades, global climate change 1 has caused profound biological changes across the planet 2–6. However, there is a great disparity in the strength of evidence among different ecosystems and ...between hemispheres: changes on land have been well documented through long-term studies, but similar direct evidence for impacts of warming is virtually absent from the oceans 3, 7, where only a few studies on individual species of intertidal invertebrates, plankton, and commercially important fish in the North Atlantic and North Pacific exist. This disparity of evidence is precarious for biological conservation because of the critical role of the marine realm in regulating the Earth's environmental and ecological functions, and the associated socioeconomic well-being of humans 8. We interrogated a database of >20,000 herbarium records of macroalgae collected in Australia since the 1940s and documented changes in communities and geographical distribution limits in both the Indian and Pacific Oceans, consistent with rapid warming over the past five decades 9, 10. We show that continued warming might drive potentially hundreds of species toward and beyond the edge of the Australian continent where sustained retreat is impossible. The potential for global extinctions is profound considering the many endemic seaweeds and seaweed-dependent marine organisms in temperate Australia.
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► Modern seaweed communities have become similar to past communities at lower latitudes ► Temperate species have experienced median shifts of 0.5° to 1.9° latitude poleward ► Given future warming, up to ∼25% of species might retract toward extinction ► Impacts are consistent with observed warming in both the Indian and Pacific Oceans
Many free-ranging predators have to make foraging decisions with little, if any, knowledge of present resource distribution and availability. The optimal search strategy they should use to maximize ...encounter rates with prey in heterogeneous natural environments remains a largely unresolved issue in ecology. Lévy walks are specialized random walks giving rise to fractal movement trajectories that may represent an optimal solution for searching complex landscapes. However, the adaptive significance of this putative strategy in response to natural prey distributions remains untested. Here we analyse over a million movement displacements recorded from animal-attached electronic tags to show that diverse marine predators-sharks, bony fishes, sea turtles and penguins-exhibit Lévy-walk-like behaviour close to a theoretical optimum. Prey density distributions also display Lévy-like fractal patterns, suggesting response movements by predators to prey distributions. Simulations show that predators have higher encounter rates when adopting Lévy-type foraging in natural-like prey fields compared with purely random landscapes. This is consistent with the hypothesis that observed search patterns are adapted to observed statistical patterns of the landscape. This may explain why Lévy-like behaviour seems to be widespread among diverse organisms, from microbes to humans, as a 'rule' that evolved in response to patchy resource distributions.
AIMS: Australia is among one of the world’s wealthiest nations; yet, its relatively small human population (22.5 million) has been responsible for extensive deforestation and forest degradation since ...European settlement in the late 18th century. Despite most (∼75%) of Australia’s 7.6 million-km2 area being covered in inhospitable deserts or arid lands generally unsuitable to forest growth, the coastal periphery has witnessed a rapid decline in forest cover and quality, especially over the last 60 years. Here I document the rates of forest loss and degradation in Australia based on a thorough review of existing literature and unpublished data. IMPORTANT FINDINGS: Overall, Australia has lost nearly 40% of its forests, but much of the remaining native vegetation is highly fragmented. As European colonists expanded in the late 18th and the early 19th centuries, deforestation occurred mainly on the most fertile soils nearest to the coast. In the 1950s, southwestern Western Australia was largely cleared for wheat production, subsequently leading to its designation as a Global Biodiversity Hotspot given its high number of endemic plant species and rapid clearing rates. Since the 1970s, the greatest rates of forest clearance have been in southeastern Queensland and northern New South Wales, although Victoria is the most cleared state. Today, degradation is occurring in the largely forested tropical north due to rapidly expanding invasive weed species and altered fire regimes. Without clear policies to regenerate degraded forests and protect existing tracts at a massive scale, Australia stands to lose a large proportion of its remaining endemic biodiversity. The most important implications of the degree to which Australian forests have disappeared or been degraded are that management must emphasize the maintenance of existing primary forest patches, as well as focus on the regeneration of matrix areas between fragments to increase native habitat area, connectivity and ecosystem functions.
The peopling of Sahul (the combined continent of Australia and New Guinea) represents the earliest continental migration and settlement event of solely anatomically modern humans, but its patterns ...and ecological drivers remain largely conceptual in the current literature. We present an advanced stochastic-ecological model to test the relative support for scenarios describing where and when the first humans entered Sahul, and their most probable routes of early settlement. The model supports a dominant entry via the northwest Sahul Shelf first, potentially followed by a second entry through New Guinea, with initial entry most consistent with 50,000 or 75,000 years ago based on comparison with bias-corrected archaeological map layers. The model's emergent properties predict that peopling of the entire continent occurred rapidly across all ecological environments within 156-208 human generations (4368-5599 years) and at a plausible rate of 0.71-0.92 km year
. More broadly, our methods and approaches can readily inform other global migration debates, with results supporting an exit of anatomically modern humans from Africa 63,000-90,000 years ago, and the peopling of Eurasia in as little as 12,000-15,000 years via inland routes.
The mechanisms leading to megafauna (>44 kg) extinctions in Late Pleistocene (126,000-12,000 years ago) Australia are highly contested because standard chronological analyses rely on scarce data of ...varying quality and ignore spatial complexity. Relevant archaeological and palaeontological records are most often also biased by differential preservation resulting in under-representated older events. Chronological analyses have attributed megafaunal extinctions to climate change, humans, or a combination of the two, but rarely consider spatial variation in extinction patterns, initial human appearance trajectories, and palaeoclimate change together. Here we develop a statistical approach to infer spatio-temporal trajectories of megafauna extirpations (local extinctions) and initial human appearance in south-eastern Australia. We identify a combined climate-human effect on regional extirpation patterns suggesting that small, mobile Aboriginal populations potentially needed access to drinkable water to survive arid ecosystems, but were simultaneously constrained by climate-dependent net landscape primary productivity. Thus, the co-drivers of megafauna extirpations were themselves constrained by the spatial distribution of climate-dependent water sources.
If habitat destruction or overexploitation of populations is severe, species loss can occur directly and abruptly. Yet the final descent to extinction is often driven by synergistic processes ...(amplifying feedbacks) that can be disconnected from the original cause of decline. We review recent observational, experimental and meta-analytic work which together show that owing to interacting and self-reinforcing processes, estimates of extinction risk for most species are more severe than previously recognised. As such, conservation actions which only target single-threat drivers risk being inadequate because of the cascading effects caused by unmanaged synergies. Future work should focus on how climate change will interact with and accelerate ongoing threats to biodiversity, such as habitat degradation, overexploitation and invasive species.
Robust data on patient-reported outcome measures comparing treatments for clinically localized prostate cancer are lacking. We investigated the effects of active monitoring, radical prostatectomy, ...and radical radiotherapy with hormones on patient-reported outcomes.
We compared patient-reported outcomes among 1643 men in the Prostate Testing for Cancer and Treatment (ProtecT) trial who completed questionnaires before diagnosis, at 6 and 12 months after randomization, and annually thereafter. Patients completed validated measures that assessed urinary, bowel, and sexual function and specific effects on quality of life, anxiety and depression, and general health. Cancer-related quality of life was assessed at 5 years. Complete 6-year data were analyzed according to the intention-to-treat principle.
The rate of questionnaire completion during follow-up was higher than 85% for most measures. Of the three treatments, prostatectomy had the greatest negative effect on sexual function and urinary continence, and although there was some recovery, these outcomes remained worse in the prostatectomy group than in the other groups throughout the trial. The negative effect of radiotherapy on sexual function was greatest at 6 months, but sexual function then recovered somewhat and was stable thereafter; radiotherapy had little effect on urinary continence. Sexual and urinary function declined gradually in the active-monitoring group. Bowel function was worse in the radiotherapy group at 6 months than in the other groups but then recovered somewhat, except for the increasing frequency of bloody stools; bowel function was unchanged in the other groups. Urinary voiding and nocturia were worse in the radiotherapy group at 6 months but then mostly recovered and were similar to the other groups after 12 months. Effects on quality of life mirrored the reported changes in function. No significant differences were observed among the groups in measures of anxiety, depression, or general health-related or cancer-related quality of life.
In this analysis of patient-reported outcomes after treatment for localized prostate cancer, patterns of severity, recovery, and decline in urinary, bowel, and sexual function and associated quality of life differed among the three groups. (Funded by the U.K. National Institute for Health Research Health Technology Assessment Program; ProtecT Current Controlled Trials number, ISRCTN20141297 ; ClinicalTrials.gov number, NCT02044172 .).
Habitat loss, climate change, over-exploitation, disease and other factors have been hypothesised in the global decline of amphibian biodiversity. However, the relative importance of and synergies ...among different drivers are still poorly understood. We present the largest global analysis of roughly 45% of known amphibians (2,583 species) to quantify the influences of life history, climate, human density and habitat loss on declines and extinction risk. Multi-model Bayesian inference reveals that large amphibian species with small geographic range and pronounced seasonality in temperature and precipitation are most likely to be Red-Listed by IUCN. Elevated habitat loss and human densities are also correlated with high threat risk. Range size, habitat loss and more extreme seasonality in precipitation contributed to decline risk in the 2,454 species that declined between 1980 and 2004, compared to species that were stable (n = 1,545) or had increased (n = 28). These empirical results show that amphibian species with restricted ranges should be urgently targeted for conservation.
Aim: Understanding the relative importance of climatic and non-climatic distribution drivers for co-occurring, functionally similar species is required to assess potential consequences of climate ...change. This understanding is, however, lacking for most ecosystems. We address this knowledge gap and forecast changes in distribution for habitat-forming seaweeds in one of the world's most species-rich temperate reef ecosystems. Location: The Great Southern Reef. The full extent of Australia's temperate coastline. Methods: We assessed relationships between climatic and non-climatic environmental data known to influence seaweed, and the presence of 15 habitat-forming seaweeds. Distributional data (herbarium records) were analysed with MAXENT and generalized linear and additive models, to construct species distribution models at 0.2° spatial resolution, and project possible distribution shifts under the RCP 6.0 (medium) and 2.6 (conservative) emissions scenarios of ocean warming for 2100. Results: Summer temperatures, and to a lesser extent winter temperatures, were the strongest distribution predictors for temperate habitat-forming seaweeds in Australia. Projections for 2100 predicted major poleward shifts for 13 of the 15 species, on average losing 78% (range: 36%-100%) of their current distributions under RCP 6.0 and 62% (range: 27%-100%) under RCP 2.6. The giant kelp (Macrocystis pyrifera) and three prominent fucoids (Durvillaea potatorum, Xiphophora chondrophylla and Phyllospora comosa) were predicted to become extinct from Australia under RCP 6.0. Many species currently distributed up the west and east coasts, including the dominant kelp Ecklonia radiata (71% and 49% estimated loss for RPC 6.0 and 2.6, respectively), were predicted to become restricted to the south coast. Main conclusions: In close accordance with emerging observations in Australia and globally, our study predicted major range contractions of temperate seaweeds in coming decades. These changes will likely have significant impacts on marine biodiversity and ecosystem functioning because large seaweeds are foundation species for 100s of habitat-associated plants and animals, many of which are socio-economically important and endemic to southern Australia.
All is not well for biodiversity in the tropics. Despite recent debate over the extent of future tropical extinctions and the effectiveness of reserve systems, the continued disappearance of habitat, ...soaring human population, and loss of vital ecosystem services demand immediate action. This crisis is worrying, given that tropical regions support over twoâthirds of all known species and are populated by some of the world's poorest people, who have little recourse to lower environmentalâimpact lifestyles. Recent evidence has shown that â in addition to unabated rates of forest loss â coastal development, overexploitation of wildlife, catchment modification, and habitat conversion are threatening human wellâbeing. We argue that the recent technical debate about likely extinctions masks the real issue â that, to prevent further loss of irreplaceable tropical biodiversity, we must err on the side of caution. We need to avoid inadvertently supporting political agendas that assume low future extinction rates, because this will result in further destruction of tropical biodiversity.
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