Distributions of Earth's species are changing at accelerating rates, increasingly driven by human-mediated climate change. Such changes are already altering the composition of ecological communities, but beyond conservation of natural systems, how and why does this matter? We review evidence that climate-driven species redistribution at regional to global scales affects ecosystem functioning, human well-being, and the dynamics of climate change itself. Production of natural resources required for food security, patterns of disease transmission, and processes of carbon sequestration are all altered by changes in species distribution. Consideration of these effects of biodiversity redistribution is critical yet lacking in most mitigation and adaptation strategies, including the United Nation's Sustainable Development Goals.

SignificanceHow climate change and biological invasions interact to affect biodiversity is of major concern to conservation. Quantitative evidence for the nature of climate change–invasion interactions is, however, limited. For the soil ecosystem fauna, such evidence is nonexistent. Yet across the globe, soil-dwelling animals regulate belowground functioning and have pronounced influences on aboveground dynamics. Using springtails as an exemplar taxon, widely known to have species-specific effects on below- and aboveground dynamics, we show that across a wide latitudinal span (16–54°S), alien species have greater ability to tolerate climate change-associated warming than do their indigenous counterparts. The consequences of such consistent differences are profound given globally significant invasions of soil systems by springtails.

Rates of temperature change and thermal acclimation can alter measures of temperature tolerance. Using new experimental data on springtails and data from the literature, we show that these factors interact and have consequences for estimates of organismal vulnerability to climate change at global scales.

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Thermal performance curves (TPCs) are intended to approximate the relationship between temperature and fitness, and are commonly integrated into species distributional models for understanding climate change responses. However, TPCs may vary across traits because selection and environmental sensitivity (plasticity) differ across traits or because the timing and duration of the temperature exposure, here termed time scale, may alter trait variation. Yet, the extent to which TPCs vary temporally and across traits is rarely considered in assessments of climate change responses. Using a common garden approach, we estimated TPCs for standard metabolic rate (SMR), and activity in Drosophila melanogaster at three test temperatures (16, 25 and 30°C), using flies from each of six developmental temperatures (16, 18, 20, 25, 28 and 30°C). We examined the effects of time scale of temperature exposure (minutes/ hours versus days/weeks) in altering TPC shape and position, and commonly used descriptors of the TPC: thermal optimum (T opt), thermal limits (T min and T max) and thermal breadth (T br). In addition, we collated previously published estimates of TPCs for fecundity and egg-to-adult viability in D. melanogaster. We found that the descriptors of the TPCs varied across traits (egg-to-adult viability, SMR, activity and fecundity), but variation in TPCs within these traits was small across studies when measured at the same time scales. The time scale at which traits were measured contributed to greater variation in TPCs than the observed variance across traits, although the relative importance of time scale differed depending on the trait (activity versus fecundity). Variation in the TPC across traits and time scales suggests that TPCs using single traits may not be an accurate predictor of fitness and thermal adaptation across environments.

Aim:We investigated turnover and richness in Antarctic springtails to understand largescale patterns in soil faunal diversity and how these are altered by biological invasions.Location: Antarctica and the Southern Ocean Islands.Taxon: Collembola (springtails). Methods:We developed a database of all springtail species recorded from the Antarctic region. The relationship of species richness and turnover to high-resolution environmental data was explored using generalized linear models and generalized dissimilarity models, and compared among indigenous and introduced species. Endemicity and species turnover were assessed using beta-diversity and multi-site zeta diversity metrics to explore whether introduced species have homogenized assemblages across the region.Results: Indigenous, endemic and introduced species richness covaried positively with temperature. Endemic richness was further related to thermal heterogeneity, and introduced species richness to human occupancy. Indigenous and introduced species richness covaried positively. Species turnover across the region was high, and the introduction of non-indigenous species further differentiated assemblages.Species similarity between sites was not related to distance, nor was geographic isolation correlated with species richness. Assemblage turnover was influenced by the area and temperature range of islands. Main conclusions:Energy availability appears to be the primary covariate of species richness, with human presence additionally influencing introduced species richness, in agreement with other soil-dwelling taxa. Dispersal limitation surprisingly does not seem to be important in structuring these assemblages, nor does island age appear to affect richness; this may in part reflect the severe glacial history of the region. The differentiating effect of introduced species on assemblages suggests that anthropogenic introductions originate from distinct source pools, challenging common assumptions for the Antarctic. Positive covariance between indigenous and introduced species richness accords with the "rich get richer" hypothesis. Thus, the most biotically diverse terrestrial areas of Antarctica may be the most prone to future biological invasion. K E Y W O R D Salien species, endemicity, island biogeography, richness, soil biota, turnover

As global climates change, alien species are anticipated to have a growing advantage relative to their indigenous counterparts, mediated through consistent trait differences between the groups. These insights have largely been developed based on interspecific comparisons using multiple species examined from different locations. Whether such consistent physiological trait differences are present within assemblages is not well understood, especially for animals. Yet, it is at the assemblage level that interactions play out. Here, we examine whether physiological trait differences observed at the interspecific level are also applicable to assemblages. We focus on the Collembola, an important component of the soil fauna characterized by invasions globally, and five traits related to fitness: critical thermal maximum, minimum and range, desiccation resistance and egg development rate. We test the predictions that the alien component of a local assemblage has greater basal physiological tolerances or higher rates, and more pronounced phenotypic plasticity than the indigenous component. Basal critical thermal maximum, thermal tolerance range, desiccation resistance, optimum temperature for egg development, the rate of development at that optimum and the upper temperature limiting egg hatching success are all significantly higher, on average, for the alien than the indigenous components of the assemblage. Outcomes for critical thermal minimum are variable. No significant differences in phenotypic plasticity exist between the alien and indigenous components of the assemblage. These results are consistent with previous interspecific studies investigating basal thermal tolerance limits and development rates and their phenotypic plasticity, in arthropods, but are inconsistent with results from previous work on desiccation resistance. Thus, for the Collembola, the anticipated advantage of alien over indigenous species under warming and drying is likely to be manifest in local assemblages, globally.

Belowground biodiversity Taxonomy Endemism (6.4 and 7.7%) proportion of globally described diversity. Endemism is high for most groups, ranging from 33-92%. However, major knowledge gaps exist for most soil biota groups. While sampling has been relatively comprehensive in some areas for a few groups (particularly those with direct socioeconomic impacts), the Nama-Karoo, Northern Cape and Eastern Cape are poorly sampled. Natural soils in biodiversity hotspots, such as the Fynbos Biome, are also understudied. We argue that a more integrative approach to acquiring foundational knowledge in soil biodiversity is needed if applied soil research is to be effective in ensuring sustainable soil health. Considerable investment will be required to bring our understanding of the soil biodiversity in this megadiverse region to a level where the Millennium Development Goals can be reached.