The Southern Ocean climate has undergone significant changes over the last several decades, which has had consequences for conditions on the few small islands scattered across the region. Previous investigations of climate changes on the Southern Ocean Islands (SOIs) have examined single climate variables, such as temperature, and single islands or island groups. Furthermore, these studies have tended to focus on mean values without consideration of variability and extreme events. Consequently, we currently lack a comprehensive and up-to-date analysis of biologically-relevant climate changes that have occurred on these islands. Such insights are needed to determine the exposure of these unique and potentially fragile island ecosystems to climate change and the threats and challenges that their species will face. Here, we use weather station records to quantify the climate signature of SOIs and examine trends in a set of biologically-relevant climate parameters related to temperature, precipitation, and wind. We find that comprehensive warming has occurred across these islands but with important nuances, including differences in the rate of increase in minimum and maximum temperature contributing to increases in diurnal temperature range. In contrast, precipitation changes have been highly localised, with severe drying on Marion and Crozet Islands in the Indian Ocean sector and wetting on Macquarie Island in the Pacific Ocean sector. Changes in wind speed have been idiosyncratic but have important consequences in combination with changes in other variables. Some key implications of these changes for the SOI ecosystems are discussed.

Antarctica is designated as a natural reserve devoted to peace and science, with Antarctic Specially Protected Areas (ASPAs) serving as the primary instrument for area-based biodiversity protection. However, the existing ASPA network lacks the comprehensiveness and representativeness required under Annex V, Article 3(2), of the Madrid Protocol. We demonstrated the application of systematic conservation planning to explore the trade-offs underlying protection at a continent-wide scale, focusing on the principles of comprehensiveness and representativeness. These principles are the foundations of designing an effective protected area system that ensures all biodiversity features and their diversity are captured. We investigated how systematic conservation planning applies in the Antarctic and evaluated the impact of alternative species targets and cost measures on performance and area selection. We found that cost assumptions had a greater influence than species target formulation on spatial priorities, and access costs based on proximity to research stations systematically disadvantaged remote species. Furthermore, our results demonstrated that comprehensive and representative protection could be achieved by balancing the placement of protected areas at varying distances from research stations. Finally, stakeholder engagement must occur throughout the process if this approach is to be formally undertaken through the Antarctic Treaty System.

Invasive species are a significant threat to marine ecosystems, contributing to biodiversity loss and ecosystem changes. Biofouling, the accumulation of aquatic organisms on vessel hulls, is one of the main pathways for invasive species worldwide, with invasive species present in nearly all marine ecosystems. Antarctica currently remains free of known established populations of marine non-native species. Vessel surveys have, however, identified diverse biofouling communities on Antarctic-bound vessels. Here, we evaluate the effectiveness of biofouling guidelines in place worldwide, in an Antarctic context, assessing whether a comprehensive international biofouling management agreement could benefit the region. Guided by the International Maritime Organization's GloFouling Partnership's guidelines and building on recent work within the Antarctic Treaty System, we review the risks posed by biofouling, examine the applicability of existing management strategies, and identify technical elements for a comprehensive biofouling agreement tailored to Antarctica. The implementation of risk-based biofouling policies, through the Antarctic Treaty System in the departure ports of Antarctic vessels is proposed. Given the increasing vessel activity in the Antarctic and rapidly changing environmental conditions as a result of climate change, implementing specific biofouling regulations will further enable the Antarctic Treaty System's stakeholders to discharge their obligations to protect Antarctica's unique marine ecosystems and biodiversity.

Removing invasive species from islands is one of the most effective conservation strategies globally, yet the broader ecosystem and climate co-benefits of such interventions remain poorly quantified as long-term monitoring is uncommon, especially on remote islands. We developed a globally scalable, spatially explicit framework that uses Landsat satellite data to track ecosystem change following conservation interventions on islands. Using c. 40 years of observations across five ecologically diverse islands, we evaluated trends in woody cover, vegetation moisture (NDMI), and productivity (NDVI, EVI, MSAVI2). We used interrupted time-series analyses to assess the effect of invasive species removal and native species reintroductions on remotely sensed indices and validated these trends against in-situ vegetation data. Vegetation responses were widespread and heterogenous across and among islands, reflecting varying extents of initial vegetation damage and differences in topographic gradients and adaptive management histories. Woody cover generally exhibited strong positive responses, particularly on islands where invasive herbivores had been removed, while changes in vegetation moisture and productivity often were spatially restricted and were moderated by elevation or landcover. Across study systems, our remote sensing trends broadly were consistent with findings from prior field and remote sensing studies, while also revealing patterns in inaccessible areas. To support real-world decision-making, we developed an open-access web application that enables natural resource managers to visualize trends and download spatial datasets. Our findings highlight the power of remote sensing to overcome monitoring barriers on remote islands and provide a new capability for tracking and guiding ecosystem change at scale.

Invasive species present a significant threat to marine ecosystems, with vessel biofouling responsible for the majority of marine invasions worldwide. The Antarctic and sub-Antarctic are some of the last regions free from known established populations of non-native marine species. Diverse biofouling communities can be transported on vessels operating in the Southern Ocean, with vessel biofouling identified as the primary vector for marine invasions in the Southern Ocean. Monitoring for non-native species in this region is challenging due to the extreme conditions and a lack of baseline biodiversity information available. We investigated the potential of passive eDNA sampling as a monitoring tool for biofouling on the icebreaking vessel MPOV Aiviq. eDNA samples were collected in the Port of Hobart, Tasmania (Australia) before, during and following in-water hull cleaning, accompanied by visual diver surveys. eDNA samples were also collected at the sub-Antarctic Macquarie Island. All eDNA samples were amplified with universal COI and 18S markers, as well as arthropod and mollusc specific markers, to gain a wide overview of taxa present. Comparison of the eDNA samples and visual surveys in Hobart provided proof of concept for the eDNA method, with known hull associated species reliably detected using eDNA. At Macquarie Island, eDNA detected 27 known hull associated taxa, including highly invasive species whose thermal range encompasses the sub-Antarctic, which could have significant impacts on native biodiversity and ecosystem function. Biofouling management for vessels operating in the Southern Ocean, with ongoing monitoring, is essential for effective biosecurity practices and to identify invasive species before they can establish.

AimThe globally significant communities of terrestrial Antarctica face an uncertain future amid growing threats in the region. Emerging data-driven approaches must be leveraged to predict and understand patterns of biodiversity across the continent. A new comprehensive database of Antarctic biological occurrence records, the Biodiversity of Ice-free Antarctica Database, will enable such novel fundamental and applied biodiversity modelling. However, there are limitations of assembled occurrence databases that, if unaccounted for, can result in poor model inference and outcomes. We perform a data quality assessment of the new database to highlight its potential and to identify data limitations that must be considered during modelling.LocationAntarctica.MethodsWe assessed the coverage of the Biodiversity of Ice-free Antarctica Database across geographic, environmental, taxonomic, and temporal dimensions at several spatial scales.ResultsWe demonstrate great potential for the database to improve our understanding of many at risk and poorly known Antarctic functional groups. We also provide evidence for limitations of the database across data dimensions, including low geographic coverage that is biased towards research stations, poor coverage of environmental variation across the landscape, and long periods since records were last collected. The magnitude of these limitations varies substantially by region and spatial scale.Main ConclusionsIn combination, data limitations have a range of implications for terrestrial Antarctic modelling, including heightening the risk of model extrapolation. For future use, we recommend prioritising, mitigating, and presenting context-specific model uncertainty, advancing strategic data collection, and exploiting shared modelling challenges elsewhere in the world to maximise the opportunities for this unique dataset to robustly advance science and conservation in Antarctica.

Marine invasive species can cause irreparable change in new environments, though not all non‐native species inevitably cause negative impacts to recipient ecosystems. Knowing which non‐native species could establish and have harmful impacts is vital to ensure the efficient use of limited resources for monitoring and surveillance, especially in less accessible regions such as the Southern Ocean. We used ensemble ecosystem modelling to predict an ensemble of plausible future scenarios of introduction and potential establishment of marine non‐native species to a known food web near Casey Station, East Antarctica. These scenarios explore potential impacts of successful invasions by five non‐native species. Non‐native species varied in their capacity to establish in the current food web following a single introduction event, though all could establish in at least some scenarios. Where the non‐native species did establish, their abundances mostly increased by between 10 and 1000 times, though some scenarios resulted in a million‐fold increase. Although most scenarios showed native species abundances only changed within 10% of the initial abundance, the establishment of an invasive species could plausibly cause substantial abundance declines to all native species. Synthesis and applications . This analysis helps us to better understand the potential range of impacts on native species and aids in developing strategies to help prevent or manage their introduction. We highlight the need for rapid detection methods, such as eDNA, to ensure any non‐native species are identified quickly in this ecosystem, particularly for those species we identified as having a high potential for negative impacts and fast population growth.

Antarctica, Earth’s least understood and most remote continent, is threatened by human disturbances and climate-related changes, underscoring the imperative for biodiversity inventories to inform conservation. Antarctic ecosystems support unique species and genetic diversity, deliver essential ecosystem services and contribute to planetary stability. We present Antarctica’s first comprehensive ecosystem classification and map of ice-free lands, which host most of the continent’s biodiversity. We used latent variables in factor analyses to partition continental-scale abiotic variation, then biotic variation represented in spatial models, and finally recognised regional-scale variation among biogeographic units. This produced a spatially explicit hierarchical classification with nine Major Environment Units (Tier 1), 33 Habitat Complexes (Tier 2) and 269 Bioregional Ecosystem Types (Tier 3) mapped at 100 m resolution and aligned with ‘level 4’ of the IUCN Global Ecosystem Typology. This comprehensive ecosystem inventory provides foundational data to inform protected area designation under the Antarctic Treaty’s Environmental Protocol and track risks to Antarctic ecosystems. Its tiered structure and workflow accommodate data scarcity and facilitate updates, promoting robustness as knowledge builds.

Antarctica, long considered an environmental sanctuary, now confronts accelerating, complex and inter-related conservation challenges. The vast size and remote location of the continent introduce substantial uncertainty in understanding and predicting these threats. Here, using strategic foresight techniques, we synthesized insights from a global horizon scan with 131 experts from 42 countries. We identified ten emerging conservation challenges across six thematic categories. Key issues included extreme precipitation, emerging animal pathogens, human pandemics, security threats, reduced cooperation among Antarctic Treaty parties and potential agricultural expansion. Several of these challenges stem from persistent underlying drivers, revealing how longstanding processes are giving rise to new and increasingly acute conservation concerns. Others, driven by global disruptions, have no historical precedent in the region but increasingly constrain decision-making and international coordination. This horizon scan reveals substantial limitations in the ability of the Antarctic Treaty system to address these challenges, underscoring the need to reassess existing governance mechanisms to protect the unique ecosystems of Antarctica and its vital role in the global climate system.

The continent of Antarctica has remained relatively free of the impacts of invasive species to date. However, Antarctica is under increasing anthropogenic pressure from human activity and climate change, elevating the risk of alien species introductions. Scientific research and the maintenance of research stations by Antarctic Treaty Parties requires the transfer of large amounts of equipment and cargo, which can harbour biosecurity risk material. Here, we assess two decades of data collected by the Australian Antarctic Division on the detection of biosecurity risk material in its facilities and vessels, both during transport and in Antarctica. We use these data to identify emerging risk species or pathways, to compare the variability in detections over time and to construct a consequence table to facilitate effective responses and resource allocation to future detections, translating our research findings into guidance for decision-makers. We find that, despite the development of policy instruments, monitoring and management for the prevention of alien species introductions to Antarctica, the risk of introductions is ongoing. We highlight areas of concern, including the transport of live spiders and the continuing potential for cargo to harbour biosecurity risk material and the benefit of ongoing training and investment and support for staff and expeditioners in the reporting of non-native species detections. Finally, we provide tools and recommendations for decision-makers and on-ground managers in the Antarctic biosecurity space, based on our research. Future studies on the establishment risk of commonly transported species would assist in improving these tools.

Conserving landscapes used by multiple stakeholder groups requires understanding of what each stakeholder values. Here we employed a semi-structured, participatory approach to identify features of value in the terrestrial Antarctic Peninsula related to biodiversity, science and tourism. Stakeholders identified 115 features, ranging from Adélie penguin colonies to sites suitable for snowshoeing tourists. We split the features into seven broad categories: science, tourism, historic, biodiversity, geographic, habitat, and intrinsic features, finding that the biodiversity category contained the most features of any one category, while science stakeholders identified the most features of any stakeholder group. Stakeholders have overlapping interests in some features, particularly for seals and seabirds, indicating that thoughtful consideration of their inclusion in future management is required. Acknowledging the importance of tourism and other social features in Antarctica and ensuring their integration into conservation planning and assessment will increase the likelihood of implementing successful environmental management strategies into the future.

Eradicating invasive predators from islands can result in substantial recovery of seabirds, but the mechanisms that drive population changes remain poorly understood. Meta-analyses have recently revealed that immigration is surprisingly important to the recovery of philopatric seabirds, but it is not known whether dispersal and philopatry interact predictably to determine rates of population growth and changes of distribution. We used whole-island surveys and long-term monitoring plots to study the abundance, distribution, and trends of 4 burrowing seabird species on Macquarie Island, Australia, to examine the legacy impacts of invasive species and ongoing responses to the world's largest eradication of multiple species of vertebrates. Wekas (Gallirallus australis) were eradicated in 1988; cats (Felis catus) in 2001; and rabbits (Oryctolagus cuniculus), black rats (Rattus rattus), and mice (Mus mus) in 2011-2014. We compared surveys from 1976-1979 and 2017-2018 and monitoring from the 1990s and 2000s onward. Antarctic prions (Pachyptila desolata) and white-headed petrels (Pterodroma lessonii) increased ∼1% per year. Blue petrels (Halobaena caerulea) and gray petrels (Procellaria cinerea) recolonized following extirpation from the main island in the 1900s but remained spatially and numerically rare in 2018. However, they increased rapidly at 14% and 10% per year, respectively, since cat eradication in 2001. Blue and gray petrel recolonization occurred on steep, dry, west-facing slopes close to ridgelines at low elevation (i.e., high-quality petrel habitat). They overlapped <5% with the distribution of Antarctic prion and white-headed petrels which occurred in suboptimal shallow, wet, east-facing slopes at high elevation. We inferred that the speed of population growth of recolonizing species was related to their numerically smaller starting size compared with the established species and was driven by immigration and selection of ideal habitat.

Signatories to the Antarctic Treaty System's Environmental Protocol are committed to preventing incursions of non-native species into Antarctica, but systematic surveillance is rare.Environmental DNA (eDNA) methods provide new opportunities for enhancing detection of non-native species and biosecurity monitoring.To be effective for Antarctic biosecurity, eDNA tests must have appropriate sensitivity and specificity to distinguish non-native from native Antarctic species, and be fit-for-purpose.This requires knowledge of the priority risk species or taxonomic groups for which eDNA surveillance will be informative, validated eDNA assays for those species or groups, and reference DNA sequences for both target non-native and related native Antarctic species.Here, we used an expert elicitation process and decision-byconsensus approach to identify and assess priority biosecurity risks for the Australian Antarctic Program (AAP) in East Antarctica, including identifying high priority non-native species and their potential transport pathways.We determined that the priority targets for biosecurity monitoring were not individual species, but rather broader taxonomic groups such as mussels (Mytilus species), tunicates (Ascidiacea), springtails (Collembola), and grasses (Poaceae).These groups each include multiple species with high risks of introduction to and/or establishment in Antarctica.The most appropriate eDNA methods for the AAP must be capable of detecting a range of species within these high-risk groups (e.g., eDNA metabarcoding).We conclude that the most beneficial Antarctic eDNA biosecurity applications include surveillance of marine species in nearshore environments, terrestrial invertebrates, and biofouling species on vessels visiting Antarctica.An urgent need exists to identify suitable genetic markers for detecting priority species groups, establish baseline terrestrial and marine biodiversity for Antarctic stations, and develop eDNA sampling methods for detecting biofouling organisms.

Marine invasive species (MIS) can cause irreparable change in new environments, though only 1 in 10 invasive species cause negative impacts to recipient ecosystems. Knowledge of which invasive species could have negative impacts helps ensure that limited resources available for MIS monitoring and management are deployed most effectively. This is particularly true in areas that are difficult to access, such as the Southern Ocean. We used an ensemble ecosystem model to explore the impact of potential future invasions by seven groups of marine invasive species on an Antarctic coastal marine food web. Although most simulations showed native species abundances only changed within 10% of the initial abundance, the establishment of a MIS could plausibly cause significant abundance declines to all native species. This analysis helps us to better understand the potential range of impacts on native species and aid the development of strategies to help prevent or manage their introduction.

Antarctic terrestrial biodiversity faces multiple threats, from invasive species to climate change. Yet no large-scale assessments of threat management strategies exist. Applying a structured participatory approach, we demonstrate that existing conservation efforts are insufficient in a changing world, estimating that 65% (at best 37%, at worst 97%) of native terrestrial taxa and land-associated seabirds are likely to decline by 2100 under current trajectories. Emperor penguins are identified as the most vulnerable taxon, followed by other seabirds and dry soil nematodes. We find that implementing 10 key threat management strategies in parallel, at an estimated present-day equivalent annual cost of US$23 million, could benefit up to 84% of Antarctic taxa. Climate change is identified as the most pervasive threat to Antarctic biodiversity and influencing global policy to effectively limit climate change is the most beneficial conservation strategy. However, minimising impacts of human activities and improved planning and management of new infrastructure projects are cost-effective and will help to minimise regional threats. Simultaneous global and regional efforts are critical to secure Antarctic biodiversity for future generations.

Monitoring and understanding Antarctica is critical for conservation of its values. Remote sensing has been increasingly employed to observe large areas at higher frequency than traditional monitoring methods, enabling systematic assessments at low cost. However, currently there are limitations in the ability of the available remote sensing tools to answer the most pressing scientific, ecological, and biological questions associated with anthropogenic impacts, including climate change, in Antarctica. Here we summarise the latest findings on remote sensing tools and techniques, identifying the gaps and highlighting priority areas for future development. Major ongoing challenges concern the intensive cloud coverage and ephemeral snow cover that prevent ongoing observations of ice-free areas and the fine spatial scales required to undertake assessments of terrestrial ecosystems, their biota, and the human footprint. Opportunities arise in the realms of advanced statistical techniques to harness the potential of increasingly available data from orbital satellites and Unmanned Aerial Systems also commonly known as drones, at multiple scales and resolutions. We conclude that harnessing emerging technological advances in remote sensing will enable new understanding and ultimately protection of Antarctic ecosystems.

Invasive mammal eradications are widely used for managing island ecosystems. However, tracking the outcomes of such large-scale, whole ecosystem projects is challenging and costly, and monitoring all components of an ecosystem is near impossible. Instead, indicators of ecosystem change may provide more practical and integrated measures of ecosystem response to eradications. As high-order marine predators, seabirds subsidise island ecosystems with nutrients isotopically enriched in nitrogen. Invasive mammals have caused a global decline of seabirds on islands, reducing this nutrient subsidisation. Following eradications, nitrogen stable isotope analysis may provide a useful and resource-efficient indicator of ecosystem functional change on eradicated islands. However, isotope ratios are affected by a myriad of factors, with potential sources of variation being introduced by spatial and temporal variation in sampling, and within and between different taxa and ecosystem components. To correctly attribute isotopic change to post-eradication ecosystem function change, these confounding variables need to be understood. To address this need, we analysed stable isotopes of nitrogen in soil, plant, spider, and seabird guano samples collected at different distances from seabird colonies and at different stages of the short-tailed shearwater breeding cycle on six island sites around south-eastern Tasmania, Australia. Across these cool, temperate islands we detected no temporal variability in δ15N throughout the breeding season. However, there was notable spatial variability in δ15N values. The effects of seabird-derived nutrient subsidisation were highly localised with high δ15N values found inside seabird colonies and then rapidly decreasing from the colony boundary. Higher δ15N values also occurred in areas of higher burrow density within a colony. Variability in δ15N values also existed both within and between ecosystem components. Our results highlight the importance of context dependency when using ecological indicators and have important implications for the design, implementation and interpretation of studies employing stable isotopes as indicators for ecosystem change. We provide recommendations for designing future stable isotope studies on seabird islands.

Maximising survey efficiency can help reduce the tradeoff between spending limited conservation resources on identifying population changes and responding to those changes through management. Burrow-nesting seabirds are particularly challenging to survey because nests cannot be counted directly. We evaluated a stratified random survey design for generating unbiased population estimates simultaneously for four petrel species nesting on Macquarie Island, Australia, where the survey cue, burrow entrances, is similar for all species. We also compared the use of design-based and model-based analyses for minimising uncertainty in estimates. We recorded 2845 Antarctic prion burrows, 306 white-headed petrel burrows and two blue petrel burrows while distance-sampling along 154 km of transects. For blue petrels and grey petrels, we completed nocturnal searches along a further 71 km and searched 249 km of tracks during follow-up ground searches. We failed to generate unbiased population estimates for two rare and localised species, blue and grey petrels, from our stratified random survey. Only for the most widespread and abundant species, Antarctic prion, did the estimate have reasonable power to detect a rapid population change. Model-based analyses of the stratified random survey data did not improve upon traditional design-based analyses in terms of uncertainty in population estimates, but they did provide useful spatial representation of current populations. Models that used the targeted survey data did not reflect current population sizes and distributions of the two rare and localised species. We found that when species ecologies, distributions and abundances vary, a multi-method approach to surveys is needed. Species with low abundance that occur patchily across large islands are likely to be best estimated using targeted surveys, whereas widespread and abundant species can be accurately and precisely estimated from randomised surveys using informative model-based analyses.