Rachel I. Leihy

The number of species introduced outside of their historical ranges by human activity continues to rise ¹ . A subset of these species establishes, form self-sustaining populations, and some – invasive alien species – go on to cause substantial harm to biodiversity and ecosystems ² . Preventing new invasive alien species from establishing is the key focus of interventions, because post-establishment management is costly and often fails ^3,4 . However, it remains unclear how effective multilateral efforts have been in curbing the rise. Here we show that the emergence of new invasive alien species across countries is slowing, and trends are similarly negative across geographically diverse countries. Using data and modelling advances, we find a 35% reduction in the establishment of new invasive alien species over a policy-relevant 50-year time frame. The findings directly inform the assessment of progress for the invasive alien species target of the Kunming-Montreal Global Biodiversity Framework ⁵ , and provide a global baseline for monitoring rates of invasive alien species establishment. Furthermore, the slowdown suggests that policy and investment over recent decades to prevent invasive alien species from entering and establishing in countries have had a positive effect.

Reducing the rates and impacts of biological invasions is a major policy goal of international biodiversity agreements. Yet the extent to which this goal is being achieved and the agreements hence successful in this respect remains unclear. Here we use a comprehensive record of alien species introduction in the terrestrial Antarctic, including its surrounding Southern Ocean Islands, spanning 115 years (1900–2015), to quantify the impact of biosecurity policy on alien species introduction rates in the region, where invasive alien species are a primary environmental conservation threat and management priority. We show that although many parts of the Antarctic have been colonized by non‐indigenous taxa, recent rates of introduction appear to be slowing or static in most parts, compared with increases in the past. Our results vindicate the regional Antarctic focus on biosecurity measures, but also demonstrate the need for stricter enforcement due to rapid socio‐environmental changes.

Mosses play a key role in Antarctic ecosystems. Understanding of moss diversity and its likely drivers across Antarctica is, however, limited, as is the extent to which Antarctic Specially Protected Areas (ASPAs) represent this diversity. Both are important given changing climates and direct human impacts in the region. Here we investigate variation in moss diversity, the frequency distribution of their range sizes, and their continent‐wide conservation. Richness is positively related to temperature, but negatively related to latitude, distance from bird colonies and geothermal sites; terrain roughness showed weak, yet positive, effects. Beta‐diversity is similar to that found for assemblages separated by long distances, dominated by species turnover. Multi‐site turnover (zeta diversity) suggests that niche‐related mechanisms are likely more responsible for diversity patterns than neutral mechanisms, despite the significant role wind‐driven dispersal is thought to play in structuring Antarctic biodiversity patterns. The frequency distribution of range sizes of mosses was right skewed, indicating that several moss species have very small range sizes, while a few species have larger ranges. Where ASPAs include mosses, richness varies between 1 and 41 species, with 65.1% (71 species) of the 109 species known from the continent included in the ASPA network. Twenty‐four species lie within 25 km² radius of an ASPA, and 14 species beyond this distance could be considered relatively more difficult to protect. These findings lend support to the proposal that changing temperatures and expanding ice‐free areas will substantially increase Antarctica's diversity. Nonetheless, the mosses are reasonably well represented by the ASPA network, contrasting with other Antarctic taxa.

Reducing the rates and impacts of biological invasions is a major policy goal of international biodiversity agreements. Yet the extent to which this goal is being achieved and the agreements hence successful in this respect remains unclear. Here we use a comprehensive record of alien species introduction in the terrestrial Antarctic, including its surrounding Southern Ocean Islands, spanning 115 years (1900–2015), to quantify the impact of biosecurity policy on alien species introduction rates in the region, where invasive alien species are a primary environmental conservation threat and management priority. We show that although many parts of the Antarctic have been colonised by non-indigenous taxa, recent rates of introduction appear to be slowing or static in most parts, compared with increases in the past. Our results vindicate the regional Antarctic focus on biosecurity measures, but also demonstrate the need for stricter enforcement due to rapid socio-environmental changes. Three key points: Biological invasions present a large and growing threat to Antarctic ecosystems under climate change and expanding human activity Over the 20 ^th century, there was no trend in alien species introduction rate in five Antarctic regions and a significantly increasing trend in the remaining five regions Despite this variation, in most regions, the number of introductions remains low, indicating that Antarctic biosecurity has been effective at slowing the rate of introduction

Open data on biological invasions are particularly critical in regions that are co-governed and/or where multiple independent parties have responsibility for preventing and controlling invasive alien species. The Antarctic is one such region where, in spite of multiple examples of invasion policy and management success, open, centralised data are not yet available. This dataset provides current and comprehensive information available on the identity, localities, establishment, eradication status, dates of introduction, habitat, and evidence of impact of known introduced and invasive alien species for the terrestrial and freshwater Antarctic and Southern Ocean region. It includes 3066 records for 1204 taxa and 36 individual localities. The evidence indicates that close to half of these species are not having an invasive impact, and that ~ 13% of records are of species considered locally invasive. The data are provided using current biodiversity and invasive alien species data and terminology standards. They provide a baseline for updating and maintaining the foundational knowledge needed to halt the rapidly growing risk of biological invasion in the region.

Research in global change ecology relies heavily on global climatic grids derived from estimates of air temperature in open areas at around 2 m above the ground. These climatic grids do not reflect conditions below vegetation canopies and near the ground surface, where critical ecosystem functions occur and most terrestrial species reside. Here, we provide global maps of soil temperature and bioclimatic variables at a 1‐km²resolution for 0–5 and 5–15 cm soil depth. These maps were created by calculating the difference (i.e. offset) between in situ soil temperature measurements, based on time series from over 1200 1‐km²pixels (summarized from 8519 unique temperature sensors) across all the world's major terrestrial biomes, and coarse‐grained air temperature estimates from ERA5‐Land (an atmospheric reanalysis by the European Centre for Medium‐Range Weather Forecasts). We show that mean annual soil temperature differs markedly from the corresponding gridded air temperature, by up to 10°C (mean = 3.0 ± 2.1°C), with substantial variation across biomes and seasons. Over the year, soils in cold and/or dry biomes are substantially warmer (+3.6 ± 2.3°C) than gridded air temperature, whereas soils in warm and humid environments are on average slightly cooler (−0.7 ± 2.3°C). The observed substantial and biome‐specific offsets emphasize that the projected impacts of climate and climate change on near‐surface biodiversity and ecosystem functioning are inaccurately assessed when air rather than soil temperature is used, especially in cold environments. The global soil‐related bioclimatic variables provided here are an important step forward for any application in ecology and related disciplines. Nevertheless, we highlight the need to fill remaining geographic gaps by collecting more in situ measurements of microclimate conditions to further enhance the spatiotemporal resolution of global soil temperature products for ecological applications.

Terrestrial species on islands often show reduced dispersal abilities. For insects, the generality of explanations for island flight loss remains contentious. Although habitat stability is considered the most plausible explanation, others are frequently highlighted. Adopting a strong inference approach, we examined the hypotheses proposed to account for the prevalence of flightlessness in island insect assemblages, for a region long suspected to be globally unusual in this regard—the Southern Ocean Islands (SOIs). Combining comprehensive faunal inventories, species' morphological information, and environmental variables from 28 SOIs, we provide the first quantitative evidence that flightlessness is exceptionally prevalent among indigenous SOI insect species (47%). Prevalence among species which have evolved elsewhere is much lower: Arctic island species (8%), species introduced to the SOIs (17%), and globally (estimated as approx. 5%). Variation in numbers of flightless species and genera across islands is best explained by variation in wind speed, although habitat stability (thermal seasonality proxy) may play a role. Variables associated with insularity, such as island size, are generally poor predictors of flightlessness. The outcomes redirect attention to Darwin's wind hypothesis. They suggest, however, that wind selects for flightlessness through an energy trade-off between flight and reproduction, instead of by displacement from suitable habitats.

Thermal performance traits are regularly used to make forecasts of the responses of ectotherms to anthropogenic environmental change, but such forecasts do not always differentiate between fundamental and realised thermal niches. Here we determine the relative extents to which variation in the fundamental and realised thermal niches accounts for current variation in species abundance and occupancy and assess the effects of niche‐choice on future‐climate response estimations. We investigated microclimate and macroclimate temperatures alongside abundance, occupancy, critical thermal limits and foraging activity of 52 ant species (accounting for >95% individuals collected) from a regional assemblage from across the Western Cape Province, South Africa, between 2003 and 2014. Capability of a species to occupy sites experiencing the most extreme temperatures, coupled with breadth of realised niche, explained most deviance in occupancy (up to 75%), while foraging temperature range and body mass explained up to 50.5% of observed variation in mean species abundance. When realised niches are used to forecast responses to climate change, large positive and negative effects among species are predicted under future conditions, in contrast to the forecasts of minimal impacts on all species that are indicated by fundamental niche predictions.