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Banning fishing in warming coastal waters and limiting tourism and construction on land will help to protect marine mammals and seabirds.

Recent assessments of Earth’s dwindling wilderness have emphasized that Antarctica is a crucial wilderness in need of protection1,2. Yet human impacts on the continent are widespread3–5, the extent of its wilderness unquantified2and the importance thereof for biodiversity conservation unknown. Here we assemble a comprehensive record of human activity (approximately 2.7 million records, spanning 200 years) and use it to quantify the extent of Antarctica’s wilderness and its representation of biodiversity. We show that 99.6% of the continent’s area can still be considered wilderness, but this area captures few biodiversity features. Pristine areas, free from human interference, cover a much smaller area (less than 32% of Antarctica) and are declining as human activity escalates6. Urgent expansion of Antarctica’s network of specially protected areas7can both reverse this trend and secure the continent’s biodiversity8–10.

Antarctic terrestrial biodiversity occurs almost exclusively in ice-free areas that cover less than 1% of the continent. Climate change will alter the extent and configuration of ice-free areas, yet the distribution and severity of these effects remain unclear. Here we quantify the impact of twenty-first century climate change on ice-free areas under two Intergovernmental Panel on Climate Change (IPCC) climate forcing scenarios using temperature-index melt modelling. Under the strongest forcing scenario, ice-free areas could expand by over 17,000 km2by the end of the century, close to a 25% increase. Most of this expansion will occur in the Antarctic Peninsula, where a threefold increase in ice-free area could drastically change the availability and connectivity of biodiversity habitat. Isolated ice-free areas will coalesce, and while the effects on biodiversity are uncertain, we hypothesize that they could eventually lead to increasing regional-scale biotic homogenization, the extinction of less-competitive species and the spread of invasive species.

The Antarctic region is one of the most inhospitable frontiers on earth for weed invasion. On Australia’s world heritage sub-Antarctic Macquarie Island only three species of invasive weeds are well established (Poa annua L., Stellaria media (L.) Vill. and Cerastium fontanum Baumg.), although isolated occurrences of other species have been found and removed. These weed species are believed to have initially been introduced through human activity, a threat which is likely to increase, although strict biosecurity is in place. All three weeds are palatable and may have been suppressed to some extent by pest herbivore (rabbit) grazing. Given the high conservation value of Macquarie Island and threats to ecosystem structure and function from weed proliferation following rabbit eradication, well targeted invasive plant control management strategies are vital. We propose that a successful restoration program for Australia’s most southerly rangeland ecosystem should integrate both control of non-native plants as well as non-native herbivores. Of the non-native plants, S. media may most easily be managed, if not eradicated, because of its more limited distribution. Little, however, is known about the soil seed bank or population dynamics after rabbit eradication, nor the effect of herbicides and non-chemical control methods in cold conditions. A current research project on this non-grass species is helping to fill these knowledge gaps, complementing and building on data collected in an earlier project on the ecology and control of the more widespread invasive grass, P. annua. With an interest in off-target herbicide impacts, our work also includes a study of the movement and fate of herbicides in the cold climate Macquarie Island soils. Research in such a remote, cold, wet and windy place presents a range of logistical challenges. Nevertheless, outcomes are informing the development of effective, low-impact control or eradication options for sub-Antarctic weeds.

During the ninth century, many sites in the Southern Maya Lowlands were abandoned as elite and commoners felt the effects of the Classic-period Maya collapse. At the same time, sites to the north and east continued to flourish. Recent climatic data indicate that, at this time, much of the Maya area experienced a significant drought. However, this drought does not appear to have uniformly affected the entire region; instead, climate appears to have acted as a mosaic, shifting through time and space. It is hypothesized that one of the key factors responsible for these variable cultural trajectories is localized and regional climate change brought about through irregular anthropogenic deforestation. These changes, when coupled with an out-of-balance cultural system, may have served as a catalyst that sent some parts of the Maya world down the path to systems failure, while other zones were able—at least, temporarily—to adjust and continue.

This article reviews currently available data on Lowland Maya sacbeob (raised roadways) to create a tripartite system of road classification and explore why the Maya built such constructions. Rather than simply classify sacbeob as “intrasite” or “intersite,” roads are divided into “local intrasite,” “core–outlier intrasite,” and “intersite” based on length and function. This classification system is then employed on a data set of 190 sacbeob to explore the degree to which it may have been some sort of a reality for the ancient Maya. The practical and symbolic aspects of roadways are also discussed, with the aim of beginning to explain why sacbeob are present at some sites while absent at others. Possibilities from environmental to temporal variation are reviewed, as are the ways in which plazas may or may not have been able to substitute for constructed routes. The Inka road system is also briefly summarized to provide an analogy to better understand Maya systems. Finally, an appeal is made to researchers to view sacbeob not as a single type of artifact, but as a class of features with a range of types and functions.

Abstract: Plants collected from diverse sites on subantarctic Macquarie Island varied by up to 30‰ in their leaf δ15N values. 15N natural abundance of plants, soils, animal excrement and atmospheric ammonia suggest that the majority of nitrogen utilised by plants growing in the vicinity of animal colonies or burrows is animal-derived. Plants growing near scavengers and animal higher in the food chain had highly enriched δ15N values (mean = 12.9‰), reflecting the highly enriched signature of these animals' excrement, while plants growing near nesting penguins and albatross, which have an intermediate food chain position, had less enriched δ15N values (>6‰). Vegetation in areas affected by rabbits had lower δ15N values (mean = 1.2‰), while the highly depleted δ15N values (below −5‰) of plants at upland plateau sites inland of penguin colonies, suggested that a portion of their nitrogen is derived from ammonia (mean 15N =−10‰) lost during the degradation of penguin guano. Vegetation in a remote area had δ15N values near −2‰. These results contrast with arctic and subarctic studies that attribute large variations in plant 15N values to nitrogen partitioning in nitrogen-limited environments. Here, plant 15N reflects the 15N of the likely nitrogen sources utilised by plants.

Reagon, Bellin and Boniface argue that traditional models of evidence-based practice focus too much on randomised controlled trials and neglect ‘the multiple truths of occupational therapy’ (Reagon et al 2010). This opinion piece points out several flaws in their argument, and suggests that it is unethical to rely on weaker evidence sources when higher quality evidence exists. Ironically, the evidence that they provide to support their argument regarding different types of evidence is itself very weak.

The article calls for the greater protection of Antarctic biodiversity as threats to the ecological integrity of Antarctica and biological invasions are accelerating. It identifies the two forms of human activities in Antarctica and mentions the growing instances of unintentional damage to the area. The result of an analysis on how well the Antarctic Specially Protected Areas under the Antarctic Treaty System represent Antarctic terrestrial biodiversity are highlighted.

Climate change leads to species range shifts and consequently to changes in diversity. For many systems, increases in diversity capacity have been forecast, with spare capacity to be taken up by a pool of weedy species moved around by humans. Few tests of this hypothesis have been undertaken, and in many temperate systems, climate change impacts may be confounded by simultaneous increases in human-related disturbance, which also promote weedy species. Areas to which weedy species are being introduced, but with little human disturbance, are therefore ideal for testing the idea. We make predictions about how such diversity capacity increases play out across elevational gradients in non-water-limited systems. Then, using modern and historical data on the elevational range of indigenous and naturalized alien vascular plant species from the relatively undisturbed sub-Antarctic Marion Island, we show that alien species have contributed significantly to filling available diversity capacity and that increases in energy availability rather than disturbance are the probable underlying cause.

The article discusses the importance of conservation management on Australian islands. It indicates that isolation and low human population in islands has allowed some of Australia's most successful conservation initiatives to date through pest eradications and species translocations. It cites the investments of 250,000 dollars by the Tasmanian state government which eradicated cats from the remote Tasman Island.