Climate change mitigation and biodiversity conservation are key forest functions, but how to pursue them jointly in timber-managed forests is still unclear. We use a Europe-wide dataset of forest multi-taxon diversity and stand structure to (i) evaluate the importance of aboveground carbon stocks in determining species richness of six taxonomic groups; (ii) assess relationships between species richness and carbon stocks; (iii) discuss the potential to jointly enhance carbon and biodiversity and policy implications. Carbon-diversity relationships are positive for several groups, but mostly when deadwood pools are considered. Forest policies should consider the complex relationship between different carbon pools and taxonomic groups. Environmental policies emphasizing carbon sequestration in aboveground living biomass may conflict with biodiversity conservation by promoting homogeneous, fast-growing forests that fail to support species diversity of multiple groups. Sustainable forest management should acknowledge that deadwood carbon instead may translate into positive outcomes for both carbon storage and biodiversity conservation. Forests are essential for both climate change mitigation and biodiversity conservation, yet how to balance these goals in managed forests remains unclear. Here, using a Europe-wide dataset, the authors find that biodiversity increases with carbon stocks, but mostly when deadwood is included.

The transferability of single or joint species distribution models ((j)SDMs) depends on their ability to predict beyond the observed environmental range and to remain consistent despite shifts in biotic interactions. Transfer accuracy may be improved by recent advances in the application of deep learning that provide greater flexibility and potentially superior predictive accuracy than traditional approaches. We implemented jSDMs with deep and machine learning algorithms and measured the transfer accuracy from continental to regional areas in communities with different species composition. We ran jSDMs with deep neural networks (DNN), elastic net (EN), and stacked SDMs (sSDM) with random forests (RF). We used 134 689 occurrence records representing 1776 species of six taxonomic groups (beetles, birds, bryophytes, fungi, lichens and plants) from 2387 forest plots in Europe. We employed an agnostic modelling approach that covered most of the environmental conditions by including more than 100 satellite-derived variables and 98 climatic variables. The predictive power of the models within the training continental area was evaluated using AUC, whereas the transfer accuracy in the regional area was evaluated with the Boyce index calculated with independent presence records. We found that the DNN-jSDMs outperformed other models at continental scale, but model transfer from continental to regional extent was less accurate. We found that the accuracy of regional predictions was higher for taxonomic groups with better representation in the continental data, such as birds, bryophytes and plants. Depending on the algorithm and the taxonomic group, we achieved acceptable (Boyce > 0) to accurate (Boyce > 0.5) transferability for 32-78% of the species. Our findings underscored the need of considering trade-offs among hyperparameter tuning, spatial scales and model complexity. Our findings also suggest that the varying biotic interaction structures and, particularly, the different species compositions of the transfer areas, may affect model transferability more than previously considered.

Similarly to a major part of temperate Europe, forest communities of Slovakia were affected by multiple anthropogenic drivers, and their significant changes were expected. Unlike large-scale tree diebacks, changes in forests understorey are less apparent, and were not sufficiently studied. To reveal its dynamics in the last six decades, we analysed 163 twice resampled permanent plots in oak, beech and spruce dominated forests. NMDS ordination was used to reveal trends in species composition changes, species turnover was tested by paired tests, mean annual rates of vascular-plant understorey properties were compared to demonstrate an acceleration of vegetation change. Species richness and species pool decreased in the oak forests, species homogenization was found in the understorey of the beech dominated stands. Rapid decrease in a herbaceous cover was observed in all broadleaved forests. Species turnover even accelerated when annual rates of Bray-Curtis dissimilarity were significantly higher in the latest period of resampling. Magnitude of changes decreased with the altitude, and the most changed understories of vascular plants were found in the oak forests. In the montane mixed forests, a shift towards the submontane beech forest understoreys was observed. Species composition and plant diversity in natural supramontane spruce forests remained relatively stable in spite of a gradual disintegration of their canopies.

As many drivers of global environmental change accelerates, it is expected that there will be an acceleration of species composition and diversity change in plant communities. These processes can be detected through longterm resurvey studies using permanent plots that were established during the period preceding the climate change. We focused on temporal changes in Carpathian beech and mixed montane forests. Vegetation data from 77 historical plots established in 1958-1976 in beech-dominated mostly unmanaged mature forests of five mountain ranges resampled in 2005-2008 and 2019-2023 were analysed. The mean annual rates of vascularplant understorey properties were compared and tested to demonstrate the acceleration. The species richness and species pool remained unchanged, while the alpha diversity (H) and evenness significantly decreased during the first decades of the 21st century, in contrast to the second half of the 20th century. The herbaceous cover decreased already in the first resurvey period during the 20th century, and this trend continued in the latest decades without acceleration. Its average dropped from 57.7% at the time of the 1st sampling (1958-1976) to 34.5% at the time of the 3rd sampling (2019-2023) along with a slow opening of the tree canopy (from 85.0% to 75.1% cover). This process present in all mountain ranges, altitudes, and bedrock types was identified as a "forest floor denudation" of beech forests. The species composition significantly changed in both resurvey periods due to high species turnover. Its rate accelerated in the second period along with the taxonomic homogenization. The overall trend in the species-composition shift was identified as a transition of the montane beech-fir or mixed forests towards the submontane beech forests of lower altitudes and higher heat load. Nevertheless, the submontane forests themselves underwent the highest rates of change in species composition, while the mixed montane communities were more stable. The understorey changes and their acceleration were attributed to the effects of climate change (warming, occurrence of heat waves, droughts and vapour pressure deficit) which likely caused a decrease of herbaceous cover after 1.9 degrees C warming, and by rapidly increasing deer densities which could contribute to the species turnover. Changes of the vascular-plant understorey accelerated but did not change the overall character of Carpathian beech and mixed montane forests as the species turnover was realised within an existing species pool. However, if the current trends of anthropogenic drivers are not stopped and reversed, we can expect even a complete change of the Carpathian forest communities..

Aims: We introduce ReSurveyEurope - a new data source of resurveyed vegetation plots in Europe, compiled by a collaborative network of vegetation scientists. We describe the scope of this initiative, provide an overview of currently available data, governance, data contribution rules, and accessibility. In addition, we outline further steps, including potential research questions. Results: ReSurveyEurope includes resurveyed vegetation plots from all habitats. Version 1.0 of ReSurveyEurope contains 283,135 observations (i.e., individual surveys of each plot) from 79,190 plots sampled in 449 independent resurvey projects. Of these, 62,139 (78%) are permanent plots, that is, marked in situ, or located with GPS, which allow for high spatial accuracy in resurvey. The remaining 17,051 (22%) plots are from studies in which plots from the initial survey could not be exactly relocated. Four data sets, which together account for 28,470 (36%) plots, provide only presence/absence information on plant species, while the remaining 50,720 (64%) plots contain abundance information (e.g., percentage cover or cover-abundance classes such as variants of the Braun-Blanquet scale). The oldest plots were sampled in 1911 in the Swiss Alps, while most plots were sampled between 1950 and 2020. Conclusions: ReSurveyEurope is a new resource to address a wide range of research questions on fine-scale changes in European vegetation. The initiative is devoted to an inclusive and transparent governance and data usage approach, based on slightly adapted rules of the well-established European Vegetation Archive (EVA). ReSurvey:Europe data are ready for use, and proposals for analyses of the data set can be submitted at any time to the coordinators. Still, further data contributions are highly welcome.

Questions: The expansion of Calamagrostis epigejos poses a significant threat to the biodiversity of mountain grasslands. We asked whether grasslands dominated by C. epigejos can be restored through mowing and the application of hemiparasitic Rhinanthus alectorolophus. Location: Carpathian Violion caninae alliance mountain grassland close to Vrchslatina, Veporsk & eacute; vrchy Mts, Slovakia. Methods: We conducted a before-after control-impact experiment in a grassland entirely dominated by C. epigejos: six blocks, each with four treatment combinations: (i) mowing once in summer, (ii) mowing in summer and autumn, (iii) mowing in summer and seed sowing of R. alectorolophus, (iv) mowing in summer and autumn along with seed sowing of R. alectorolophus. We monitored the above-ground biomass of C. epigejos, R. alectorolophus, the combined above-ground biomass of other species, and the vegetation composition annually from 2014 to 2017. Linear mixed-effect models and redundancy analysis (RDA) were employed to analyze the effects of the treatments on C. epigejos and community parameters. Results: Sowing established R. alectorolophus at the plots mown twice in the first year, but its density strongly declined in subsequent years. R. alectorolophus and mowing twice significantly reduced C. epigejos biomass and herb layer cover. They also increased community evenness and the ratio between other species and C. epigejos biomass with a more pronounced effect on the plots where R. alectorolophus was applied. Mowing twice led to increased species richness, evenness, the number of target grassland species and their proportion in the community. R. alectorolophus had an additional positive impact on community evenness and the proportion of target species. RDA identified R. alectorolophus as the main driver of the directional community change triggered by the experimental treatments. Conclusion: Mowing twice per season proves to be an efficient restoration management strategy for mountain grasslands dominated by C. epigejos. Sowing R. alectorolophus, however, may be employed as an additional measure to accelerate the decline of C. epigejos at the outset of the restoration process and enhance community structure and composition.

Managing forests to sustain their diversity and functioning is a major challenge in a changing world. Despite the key role of understory vegetation in driving forest biodiversity, regeneration and functioning, few studies address the functional dimensions of understory vegetation response to silvicultural management. We assessed the influence of the silvicultural regimes on the functional diversity and redundancy of European forest understory. We gathered vascular plant abundance data from more than 2000 plots in European forests, each associated with one out of the five most widespread silvicultural regimes. We used generalized linear mixed models to assess the effect of different silvicultural regimes on understory functional diversity (Rao's quadratic entropy) and functional redundancy, while accounting for climate and soil conditions, and explored the reciprocal relationship between three diversity components (functional diversity, redundancy and dominance) across silvicultural regimes through a ternary diversity diagram. Intensive silvicultural regimes are associated with a decrease in functional diversity and an increase in functional redundancy, compared with unmanaged conditions. This means that although intensive management may buffer communities' functions against species or functional losses, it also limits the range of understory response to environmental changes. Policy implications. Different silvicultural regimes influence different facets of understory functional features. While unmanaged forests can be used as a reference to design silvicultural practices in compliance with biodiversity conservation targets, different silvicultural options should be balanced at landscape scale to sustain the multiple forest functions that human societies are increasingly demanding. Different silvicultural regimes influence different facets of understory functional features. While unmanaged forests can be used as a reference to design silvicultural practices in compliance with biodiversity conservation targets, different silvicultural options should be balanced at landscape scale to sustain the multiple forest functions that human societies are increasingly demanding.image

Nature conservation in the Carpathians focuses on primary forest remnants as biodiversity hotspots. They are often recognized by structural attributes such as tree size heterogeneity and the occurrence of ancient trees. Studies from managed forests or on gradients from managed to unmanaged forests suggest that structure heterogeneity increases herb layer diversity. We have focused on mountain beech primary forests and tested the effect of tree-stand structure, and natural disturbance history on the herb vegetation composition and richness in 150 plots across Slovakia to complement the recent evidence. The overall herb species richness is declining with the increase of recent tree and shrub layer cover, and this decline was also observed for the richness of forest specialists, although their proportion to the other species is growing. Interestingly, we did not find any effect of canopy continuity or time since the last disturbance in the plot on the forest specialist's proportion. Our results suggest that species rich understory of primary mountain beech forests are characterized by relatively low structural complexity and low tree and shrub layer cover, and this is true also if only forest specialist species are considered. These outcomes emphasize the need for tailored strategies in monitoring and managing protected forests. With the recent landscape changes in Europe, they are important for understanding herbaceous vegetation development after the abandonment of forest use.

Forest biodiversity studies conducted across Europe use a multitude of forestry terms,often inconsistently.This hinders the comparability across studies and makes the assessment of the impacts of forest management on biodiversity highly context-dependent.Recent attempts to standardize forestry and stand description terminology mostly used a top-down approach that did not account for the perspectives and approaches of forest biodiversity experts.This work aims to establish common standards for silvicultural and vegetation definitions,creating a shared conceptual framework for a consistent study on the effects of forest management on biodiversity.We have identified both strengths and weaknesses of the silvicultural and vegetation information provided in forest biodiversity studies.While quantitative data on forest biomass and dominant tree species are frequently included,information on silvicultural activities and vegetation composition is often lacking,shallow,or based on broad and heterogeneous classifications.We discuss the existing classifications and their use in European forest biodiversity studies through a novel bottom-up and top-driven review process,and ultimately propose a common framework.This will enhance the comparability of forest biodiversity studies in Europe,and puts the basis for effective implementation and monitoring of sustainable forest management policies.The standards here proposed are potentially adaptable and applicable to other geographical areas and could be extended to other forest interventions.

Microclimate research gained renewed interest over the last decade and its importance for many ecological processes is increasingly being recognized. Consequently, the call for high-resolution microclimatic temperature grids across broad spatial extents is becoming more pressing to improve ecological models. Here, we provide a new set of open-access bioclimatic variables for microclimate temperatures of European forests at 25 × 25 m2 resolution.

Traditionally, calcareous beech forests were classified and differentiated according to vascular plants. Bryophytes were often omitted or not all substrates were sampled in relevés, and therefore, the role of bryophytes in plant community differentiation remained unclear. In this paper, we studied bryophyte species richness, composition and functional patterns in vegetation units differentiated by vascular plants. We analysed 45 phytosociological relevés from 400 m 2 plots in Fagus sylvatica -dominated forests on dolomite bedrock in Central Slovakia. The most frequent among 59 moss and 8 liverwort species was Tortella tortuosa , followed by Hypnum cupressiforme , Brachytheciastrum velutinum and Ctenidium molluscum . Average richness of bryophytes was 8.1 compared to 38.7 species of vascular plants. Seven bryophyte species were significantly linked to a particular vegetation unit. One-way ANOVA showed no noticeable differences in bryophyte species richness between vegetation units. However, it was negatively affected by xericity and positively by cover of rocks on soil surface. CCA revealed that species composition was affected significantly by xericity, cover of bare rocks and cover of tree layer. Mat and turf life forms prevailed, and both long-lived taxa/perennials and short-lived colonists formed the bryophyte layer. Observed bryophyte species grew mostly on rock, living and dead wood, and only minority of them on soil. Therefore, available substrates greatly contributed to the species richness of bryophytes and total plant diversity of the forest community. A complete investigation of substrates is necessary to assess the drivers of bryophyte species distribution and diversity, and their role in classification of calcareous beech forests.

The European biodiversity and forest strategies rely on forest sustainable management (SFM) to conserve forest biodiversity. However, current sustainability assessments hardly account for direct biodiversity indicators. We focused on forest multi-taxon biodiversity to: i) gather and map the existing information; ii) identify knowledge and research gaps; iii) discuss its research potential. We established a research network to fit data on species, standing trees, lying deadwood and sampling unit description from 34 local datasets across 3591 sampling units. A total of 8724 species were represented, with the share of common and rare species varying across taxonomic classes: some included many species with several rare ones (e.g., Insecta); others (e.g., Bryopsida) were repre-sented by few common species. Tree-related structural attributes were sampled in a subset of sampling units (2889; 2356; 2309 and 1388 respectively for diameter, height, deadwood and microhabitats). Overall, multi-taxon studies are biased towards mature forests and may underrepresent the species related to other develop-mental phases. European forest compositional categories were all represented, but beech forests were over-represented as compared to thermophilous and boreal forests. Most sampling units (94%) were referred to a habitat type of conservation concern. Existing information may support European conservation and SFM stra-tegies in: (i) methodological harmonization and coordinated monitoring; (ii) definition and testing of SFM in-dicators and thresholds; (iii) data-driven assessment of the effects of environmental and management drivers on multi-taxon forest biological and functional diversity, (iv) multi-scale forest monitoring integrating in-situ and remotely sensed information.

Microclimate is a key driver of forest dynamics and shapes the response of forest organisms to global warming. The spatial and temporal variability of microclimate is strongly affected by forest management, so it is important to know how microclimate varies along successional gradients of managed forests, and how microclimatic dynamics in managed forests differ from those in old-growth forests.We measured forest understorey microclimate along successional gradients in regularly harvested forests and old-growth beech forests affected only by natural disturbances in the Western Carpathians (Central Europe) over a period of three years. We analysed how temperature and vapour pressure deficit (VPD) depended on forest structure and stand age, and how microclimate of managed stands differed from natural old-growth forests.Across forest landscapes we found that microclimatic conditions in managed forests were much more variable than in old-growth forests. Threshold analysis indicated that it takes approximately 54 years after clearing for microclimate to recover to conditions typical of old-growth and mature managed stands.Current forest management cycles create a microclimate landscape that is more dynamic in both space and time than the conditions to which many forest organisms are adapted in old-growth temperate forests in Europe. Adopting a harvesting approach inspired by temporal dynamics of old-growth forests, such as small-scale clearings with remnant trees providing microclimate refugia, is a suitable strategy for climate smart forestry to maintain microclimate buffering in managed forests. By increasing thermal habitat continuity, such options may help integrate biodiversity conservation targets into forest management programmes under climate change.

Most European forests are used for timber production. Given the limited extent of unmanaged (and especially primary) forests, it is essential to include commercial forests in the conservation of forest biodiversity. In order to develop ecologically sustainable forest management practices, it is important to understand the management impacts on forest-dwelling organisms. Experiments allow testing the effects of alternative management strategies, and monitoring of multiple taxa informs us on the response range across forest-dwelling organisms. To provide a representative picture of the currently available information, metadata on 28 multi-taxa forest management experiments were collected from 14 European countries. We demonstrate the potential of compiling these experiments in a single network to upscale results from the local to continental level and indicate directions for future research. Among the different forest types, temperate deciduous beech and oak-dominated forests are the best represented in the multi-taxa management experiments. Of all the experimental treatments, innovative ways of traditional management techniques (e.g., gap cutting and thinning) and conservation-oriented interventions (e.g., microhabitat enrichment) provide the best opportunity for large-scale analyses. Regarding the organism groups, woody regeneration, herbs, fungi, beetles, bryophytes, birds and lichens offer the largest potential for addressing management–biodiversity relationships at the European level. We identified knowledge gaps regarding boreal, hemiboreal and broadleaved evergreen forests, the treatments of large herbivore exclusion, prescribed burning and forest floor or water manipulations, and the monitoring of soil-dwelling organisms and some vertebrate classes, e.g., amphibians, reptiles and mammals. To improve multi-site comparisons, design of future experiments should be fitted to the set-up of the ongoing projects and standardised biodiversity sampling is suggested. However, the network described here opens the way to learn lessons on the impact on forest biodiversity of different management techniques at the continental level, and thus, supports biodiversity conservation in managed forests.

Spatial heterogeneity of biodiversity is linked to environmental gradients across landscapes. In forest vegetation, trees essentially affect the forest understorey flora, not only by forming the microecological conditions but also by their competitiveness. Here, we investigate the changes in taxonomic diversity along the altitudinal gradient in forests dominated by the strongly competitive, European beech (Fagus sylvatica), considering different ecological drivers important for vegetation diversity. The response of plant species diversity to changing characteristics is mostly non-linear or has an increasing trend. This reflects the specific environments of the studied region of Western Carpathians (Central Europe), where a high variability of geological substrates and the occurrence of base-rich rocks at higher altitudes increase species diversity. The beech cover, the geological substrate and the orography were found to be the most significant factors determining the diversity patterns. The increasing trend towards higher altitudes is significant on carbonate bedrock regardless of any other studied factors. The geological conditions multiply the number of species almost twice on carbonates compared to the communities on silicates. The Veľká Fatra Mts and Slovenský raj Mts are the plant diversity hotspots of beech forests in the Western Carpathians.

Species composition of European temperate Quercus forests have undergone dramatic changes in the past century. Observed changes have largely been attributed to anthropogenic environmental changes that drove the processes of thermophilization, eutrophication, or biotic homogenization. However, ecological processes behind these changes can be difficult to explain considering the variability among regions: their history, management, landscape patterns, site properties, and vegetation types. To reveal vegetation change trends and their drivers in the subcontinental Western Carpathians, we analysed vegetation and environmental data from 158 quasipermanent plots established between 1961 and 1980 in Quercus petraea- dominated forests on the andesite bedrock of the Slovenske & PRIME; stredohorie Mountains in Slovakia (Central Europe), and we resurveyed them again between 2005 and 2020. Among alpha and gamma diversity measures, we found only slight species richness decreases. A significant shift in species composition associated with very high species turnover (64%) and a decrease in herb layer cover (by 24%) resulted in higher spatial heterogeneity of herb understoreys in the resurvey. Winning species were more thermophilous, eutrophic, and mesic/oceanic plants of lower latitudes, replacing original species of open Quercus forests. Increased temperatures was the most significant environmental driver. Climate warming corresponded not only to thermophilization, but, after interaction with management, it was also related to eutrophication of the herb layer. Eutrophication was identified as the main trend of the species composition changes (mean EIV for nutrients of winners was 5.9 compared to 4.1 of losers) even though the effect of anthropic nitrogen depositions was negligible. Successive undergrowing of Quercus canopies by more shade-casting trees (Acer campestre, Carpinus betulus, and Fagus sylvatica) in the period of decreasing management intensity was another major driver. Their increase by 8.6% in the resurveyed plots contributed to decreased species richness and they supported shade-tolerant eutrophic understorey species typical of mesic Carpinus betulus and Fagus sylvatica forests. We concluded that Quercus forests in the Western Carpathians underwent thermophilization and eutrophication, similar to the forests in densely inhabited Western Europe; however, their plant understoreys were not homogenized, and eutrophication was not driven by nitrogen depositions. Eutrophication should be recognised as the next important negative impact of global warming on ecosystems. Dramatic changes in species composition and loss of original characteristic species can only be partly halted by reducing shade-casting trees from lower tree layers in managed stands.

Temporal dynamics of temperate montane primary forests were described based on data from Central-European nature reserves in the 20th century as a long-term cycle involving tree regeneration, growth, maturation, and disintegration. However, the lack of chronosequences focusing on the herbaceous understory has limited our understanding of plant community dynamics within this developmental cycle. To address questions regarding whether the herbaceous understory follows the cyclic trajectory of the tree layer and if the properties of the tree layer drive the dynamics of the herbaceous understory, we investigated a 19-year chronosequence in ten plots (with five sampling periods) within an unmanaged primary beech-fir forest in the Western Carpathians. The vegetation data from the resampled plots, including herb species frequencies and dendrometric variables, covered a significant portion of the developmental cycle of a single plant community type. The results confirmed the cyclical nature of herbaceous understory development in terms of species composition and diversity trajectories, demonstrating transitions between developmental stages. Diversity was highest during the disintegration stage, with a rapid decline towards the growth stage, followed by a slow recovery as it progressed towards the optimum stage. Temporal responses of individual species, along with ordination analyses, allowed for the separation of taxa associated with the disintegration, growth, and optimum stages, as well as the most stable ones throughout the entire cycle. The proportion of therophytes slightly increased after gap-opening events during disintegration, geophytes were most represented during the growth stage, and hemicryptophytes culminated during the optimum stage. The composition of herb species was significantly affected by the above-ground tree biomass (AGTB), which explained 21.4% of the temporal variability. The sum of the diameter at breast height (Sum of DBH) described an additional 7.2%. The relationship between the frequency of the herbaceous understory and AGTB followed a “U” shape, while the relationship with Sum of DBH was negative and linear. The relationship between the herbaceous understory and the tree overstory is likely driven by competition for light, water, and nutrient resources. These findings provide new insights into the temporal relationships between the herbaceous understory and tree layer development, and they may inspire future studies and management strategies aimed at conserving or enhancing biodiversity in temperate forests.

Development of primeval spruce forests is driven by series of mixed severity disturbances. Disturbances and their legacies revealed by dendrochronological methods are shaping recent tree-stand structure. In this paper, we focused on the effect of disturbance history on vascular plant understorey diversity and species composition. Series of 141 plots (1000 m 2 for dendrochronology and 400 m 2 for understorey) randomly placed in primeval stands in the zone of natural montane acidophilous forests dominated by Picea abies in the Western Carpathians was sampled. Dendrochronological, dendrometric and environmental parameters were compared to understorey properties using ordination methods and Bayesian approach or multilevel linear models (GLMM). Both historical disturbances and current tree-stand structure had significant effect on understorey diversity and composition. Interactions among spruce stand properties, Vaccinium myrtillus cover and topsoil chemical properties drive understorey diversity which decrease in time from the last severe disturbance. Period of severe disturbances between 1860–1890 resulted in legacy of current, relatively homogeneous spruce stands with less diverse understorey dominated by bilberry, in contrast to heterogeneous stands (in terms of age and spatial structure) driven by small-scale lower severity disturbances which showed higher understorey diversity. As a consequence, to preserve full understorey variability in the montane spruce forests, disturbances of all magnitudes and spatial extent should be accepted as natural drivers both in the field of nature conservation and close-to-nature forestry.

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‐km 2 resolution 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‐km 2 pixels (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.