To understand how diversity is distributed in space is a fundamental aim for optimizing future species and community conservation. We examined in parallel species richness and beta diversity components of nine taxonomic groups along a finite space, represented by pastured grasslands along an elevational gradient. Beta diversity, which is assumed to bridge local alpha diversity to regional gamma diversity was partitioned into the two components turnover and nestedness and analyzed at two levels: from the lowest elevation to all other elevations, and between neighboring elevations. Species richness of vascular plants, butterflies, beetles, spiders and earthworms showed a hump-shaped relationship with increasing elevation, while it decreased linearly for grasshoppers and ants, but increased for lichens and bryophytes. For most of the groups, turnover increased with increasing elevational distance along the gradient while nestedness decreased. With regard to step-wise beta diversity, rates of turnover or nestedness did not change notably between neighboring steps for the majority of groups. Our results support the assumption that species communities occupying the same habitat significantly change along elevation, however transition seems to happen continuously and is not detectable between neighboring steps. Our findings, rather than delineating levels of major diversity losses, indicate that conservation actions targeting at a preventive protection for species and their environment in mountainous regions require the consideration of entire spatial settings.

Mountain ecosystems play an important role globally as centers of biodiversity and in providing ecosystem services to lowland populations, but are influenced by multiple global change drivers such as climate change, nitrogen deposition, or altered disturbance regimes. As global change is accelerating and the consequences for humans and nature are intensifying, there is an increasing demand for understanding and predicting the impacts and implications of global change on mountain ecosystems. Manipulation experiments are one of the major tools for testing the causal impacts of global change and establishing a mechanistic understanding of how these changes may transform the global biota from single organisms to entire ecosystems. Over the past three decades, hundreds of such experiments have been conducted in mountainous regions worldwide. To strengthen the experimental evidence for the possible ecological consequences of global change, we systematically reviewed the literature on global change experiments in mountains. We first investigated the spread of manipulation experiments to test the effects of different global change drivers on key biological and ecological processes from the organism to the ecosystem level. We then examined and discussed the balance of evidence regarding the impact of these global change drivers on biological and ecological processes, and outlined the possible consequences for mountain ecosystems. Finally, we identified research gaps and proposed future directions for global change research in mountain environments. Among the major drivers, temperature was manipulated most frequently, generally showing consistent strong impacts between biological and ecosystem processes, functional groups, and habitat types. There is also strong evidence suggesting that changes in water and nutrient availability have a direct impact on the life history and functioning of mountain organisms. Despite these important findings, there are several gaps that require urgent attention. These include experiments testing adult trees in tropical and boreal regions, assessing animal responses and biotic interactions, and investigating aquatic environments and soil systems more extensively. A broader approach that integrates experimental data with field observations and relies on international collaboration through coordinated experiments could help address these gaps and provide a more consistent and robust picture of the impacts of global change on mountain ecosystems.

Biological diversity in mountain ecosystems has been increasingly studied over the last decade. This is also the case for mountain soils, but no study to date has provided an overall synthesis of the current state of knowledge. Here we fill this gap with a first global analysis of published research on cryptogams, microorganisms, and fauna in mountain soils above the treeline, and a structured synthesis of current knowledge. Based on a corpus of almost 1400 publications and the expertise of 37 mountain soil scientists worldwide, we summarise what is known about the diversity and distribution patterns of each of these organismal groups, specifically along elevation, and provide an overview of available knowledge on the drivers explaining these patterns and their changes. In particular, we document an elevation‐dependent decrease in faunal diversity above the treeline, while for cryptogams there is an initial increase above the treeline, followed by a decrease towards the nival belt. Thus, our data confirm the key role that elevation plays in shaping the biodiversity and distribution of these organisms in mountain soils. The response of prokaryote diversity to elevation, in turn, was more diverse, whereas fungal diversity appeared to be substantially influenced by plants. As far as available, we describe key characteristics, adaptations, and functions of mountain soil species, and despite a lack of ecological information about the uncultivated majority of prokaryotes, fungi, and protists, we illustrate the remarkable and unique diversity of life forms and life histories encountered in alpine mountain soils. By applying rule‐ as well as pattern‐based literature‐mining approaches and semi‐quantitative analyses, we identified hotspots of mountain soil research in the European Alps and Central Asia and revealed significant gaps in taxonomic coverage, particularly among biocrusts, soil protists, and soil fauna. We further report thematic priorities for research on mountain soil biodiversity above the treeline and identify unanswered research questions. Building upon the outcomes of this synthesis, we conclude with a set of research opportunities for mountain soil biodiversity research worldwide. Soils in mountain ecosystems above the treeline fulfil critical functions and make essential contributions to life on land. Accordingly, seizing these opportunities and closing knowledge gaps appears crucial to enable science‐based decision making in mountain regions and formulating laws and guidelines in support of mountain soil biodiversity conservation targets.

The severe biodiversity decline in European agricultural landscapes demands a specific evaluation of the various land-use practices. Many butterflies in Europe, as an important ecological indicator and pollinator taxon, require human interventions to sustain their populations in cultivated landscapes. However, land-use changes and management intensification are currently responsible for their decline. In this study, we compare butterfly communities occurring on 93 sites in seven widely distributed land-use types, viz. extensive meadows and pastures, semi-intensive meadows, vineyards, arable land, settlements and apple orchards. We recorded a high butterfly diversity in supposedly high nature-conservation value (HNV) grasslands (extensive meadows and pastures). All other land-use types showed significantly lower diversity, with decreasing diversity from semi-intensive meadows to apple orchards. Moreover, functional traits uncovered a general trend: extensive grasslands supported communities of more specialized and sedentary species whilst all other non-HNV land-use types showed communities characterized by mobile generalists. Community composition was driven by the land-use type and explained by plant-based indicator values for nutrients and light and temperature variables. Important life-history traits further correlated with site variables confirming the shift from specialists to generalists along increasing land-use intensity gradients and the effect of the thermal environment on phenological traits. We found supporting evidence for the effectiveness of regional Agri-Environmental Measures for butterfly conservation in European cultural landscapes and for the European conservation schemes to focus at least partly on the preservation of HNV grasslands with extensive management. Furthermore, we clearly show the poor ecological state of butterfly communities in more disturbed land-use types (including urban areas) and propose adopting measures to improve butterflies’ conservation in these environments.

Ants are crucial for the functioning of many terrestrial ecosystems, but detailed knowledge of their ecological role is often lacking. This is true for high mountains where a steep environmental gradient exists from mountainous forest, densely populated by ants, to grassland habitats above the tree line, harboring a sparse ant community. We assessed ant communities in and around the tree line ecotone on five slopes in the southern-central Alps, focusing on their species diversity, community composition, and functional dimensions. Species richness and functional diversity were highest directly at the ecotone. Ant community composition was shaped by elevation and shrub cover. Further, the abundance of the dominant mound-building red wood ants (Formica s. str.) influenced the community composition of the subordinate species. We conclude that over the tree line ecotone a shift in predominance from biotic limitations in the forest to abiotic filters in the alpine environment takes place.