The construction of shelters on plants by arthropods might influence other organisms via changes in colonization, community richness, species composition, and functionality. Arthropods, including beetles, caterpillars, sawflies, spiders, and wasps often interact with host plants via the construction of shelters, building a variety of structures such as leaf ties, tents, rolls, and bags; leaf and stem galls, and hollowed out stems. Such constructs might have both an adaptive value in terms of protection (i.e., serve as shelters) but may also exert a strong influence on terrestrial community diversity in the engineered and neighboring hosts via colonization by secondary occupants. Although different traits of the host plant (e.g., physical, chemical, and architectural features) may affect the potential for ecosystem engineering by insects, such effects have been, to a certain degree, overlooked. Further analyses of how plant traits affect the occurrence of shelters may therefore enrich our understanding of the organizing principles of plant-based communities. This data set includes more than 1000 unique records of ecosystem engineering by arthropods, in the form of structures built on plants. All records have been published in the literature, and span both natural structures (91% of the records) and structures artificially created by researchers (9% of the records). The data were gathered between 1932 and 2021, across more than 50 countries and several ecosystems, ranging from polar to tropical zones. In addition to data on host plants and engineers, we aggregated data on the type of constructs and the identity of inquilines using these structures. This data set highlights the importance of these subtle structures for the organization of terrestrial arthropod communities, enabling hypotheses testing in ecological studies addressing ecosystem engineering and facilitation mediated by constructs. There are no copyright restrictions and please cite this paper when using the data in publications.

Current climate change is disrupting biotic interactions and eroding biodiversity worldwide. However, species sensitive to aridity, high temperatures, and climate variability might find shelter in microclimatic refuges, such as leaf rolls built by arthropods. To explore how the importance of leaf shelters for terrestrial arthropods changes with latitude, elevation, and climate, we conducted a distributed experiment comparing arthropods in leaf rolls versus control leaves across 52 sites along an 11,790 km latitudinal gradient. We then probed the impact of short- versus long-term climatic impacts on roll use, by comparing the relative impact of conditions during the experiment versus average, baseline conditions at the site. Leaf shelters supported larger organisms and higher arthropod biomass and species diversity than non-rolled control leaves. However, the magnitude of the leaf rolls' effect differed between long- and short-term climate conditions, metrics (species richness, biomass, and body size), and trophic groups (predators vs. herbivores). The effect of leaf rolls on predator richness was influenced only by baseline climate, increasing in magnitude in regions experiencing increased long-term aridity, regardless of latitude, elevation, and weather during the experiment. This suggests that shelter use by predators may be innate, and thus, driven by natural selection. In contrast, the effect of leaf rolls on predator biomass and predator body size decreased with increasing temperature, and increased with increasing precipitation, respectively, during the experiment. The magnitude of shelter usage by herbivores increased with the abundance of predators and decreased with increasing temperature during the experiment. Taken together, these results highlight that leaf roll use may have both proximal and ultimate causes. Projected increases in climate variability and aridity are, therefore, likely to increase the importance of biotic refugia in mitigating the effects of climate change on species persistence.

ABSTRACTDisturbances alter biodiversity via their specific characteristics, including severity and extent in the landscape, which act at different temporal and spatial scales. Biodiversity response to disturbance also depends on the community characteristics and habitat requirements of species. Untangling the mechanistic interplay of these factors has guided disturbance ecology for decades, generating mixed scientific evidence of biodiversity responses to disturbance. Understanding the impact of natural disturbances on biodiversity is increasingly important due to human‐induced changes in natural disturbance regimes. In many areas, major natural forest disturbances, such as wildfires, windstorms, and insect outbreaks, are becoming more frequent, intense, severe, and widespread due to climate change and land‐use change. Conversely, the suppression of natural disturbances threatens disturbance‐dependent biota. Using a meta‐analytic approach, we analysed a global data set (with most sampling concentrated in temperate and boreal secondary forests) of species assemblages of 26 taxonomic groups, including plants, animals, and fungi collected from forests affected by wildfires, windstorms, and insect outbreaks. The overall effect of natural disturbances on α‐diversity did not differ significantly from zero, but some taxonomic groups responded positively to disturbance, while others tended to respond negatively. Disturbance was beneficial for taxonomic groups preferring conditions associated with open canopies (e.g. hymenopterans and hoverflies), whereas ground‐dwelling groups and/or groups typically associated with shady conditions (e.g. epigeic lichens and mycorrhizal fungi) were more likely to be negatively impacted by disturbance. Across all taxonomic groups, the highest α‐diversity in disturbed forest patches occurred under moderate disturbance severity, i.e. with approximately 55% of trees killed by disturbance. We further extended our meta‐analysis by applying a unified diversity concept based on Hill numbers to estimate α‐diversity changes in different taxonomic groups across a gradient of disturbance severity measured at the stand scale and incorporating other disturbance features. We found that disturbance severity negatively affected diversity for Hill number q = 0 but not for q = 1 and q = 2, indicating that diversity–disturbance relationships are shaped by species relative abundances. Our synthesis of α‐diversity was extended by a synthesis of disturbance‐induced change in species assemblages, and revealed that disturbance changes the β‐diversity of multiple taxonomic groups, including some groups that were not affected at the α‐diversity level (birds and woody plants). Finally, we used mixed rarefaction/extrapolation to estimate biodiversity change as a function of the proportion of forests that were disturbed, i.e. the disturbance extent measured at the landscape scale. The comparison of intact and naturally disturbed forests revealed that both types of forests provide habitat for unique species assemblages, whereas species diversity in the mixture of disturbed and undisturbed forests peaked at intermediate values of disturbance extent in the simulated landscape. Hence, the relationship between α‐diversity and disturbance severity in disturbed forest stands was strikingly similar to the relationship between species richness and disturbance extent in a landscape consisting of both disturbed and undisturbed forest habitats. This result suggests that both moderate disturbance severity and moderate disturbance extent support the highest levels of biodiversity in contemporary forest landscapes.

Current climate change is disrupting biotic interactions and eroding biodiversity worldwide. However, species sensitive to drought, high temperatures and climate variability might persist in microclimatic refuges, such as leaf shelters built by arthropods. We conducted a distributed experiment across an 11,790 km latitudinal gradient to explore how the importance of leaf shelters for terrestrial arthropods changes with latitude, elevation and underlying climate. Our analyses revealed leaf shelters to be key facilitative elements for the diversity of arthropods. Predator diversity and overall biomass within shelters increased with local drought and temperature variability, regardless of latitude and elevation. In contrast, shelter usage by herbivores increased with abundance of predators on those same plants and in wetter climates. Projected increase in climatic variability and drought in certain geographic regions is therefore likely to enhance the importance of biotic refuges, especially for predators, in mitigating the impact of climate change on species persistence.

Abstract In the face of global pollinator decline, extensively managed grasslands play an important role in supporting stable pollinator communities. However, different types of extensive management may promote particular plant species and thus particular functional traits. As the functional traits of flowering plant species (e.g., flower size and shape) in a habitat help determine the identity and frequency of pollinator visitors, they can also influence the structures of plant−pollinator interaction networks (i.e., pollination networks). The aim of this study was to examine how the type of low‐intensity traditional management influences plant and pollinator composition, the structure of plant−pollinator interactions, and their mediation by floral and insect functional traits. Specifically, we compared mown wooded meadows to grazed alvar pastures in western Estonia. We found that both management types fostered equal diversity of plants and pollinators, and overlapping, though still distinct, plant and pollinator compositions. Wooded meadow pollination networks had significantly higher connectance and specialization, while alvar pasture networks achieved higher interaction diversity at a standardized sampling of interactions. Pollinators with small body sizes and short proboscis lengths were more specialized in their preference for particular plant species and the specialization of individual pollinators was higher in alvar pastures than in wooded meadows. All in all, the two management types promoted diverse plant and pollinator communities, which enabled the development of equally even and nested pollination networks. The same generalist plant and pollinator species were important for the pollination networks of both wooded meadows and alvar pastures; however, they were complemented by management‐specific species, which accounted for differences in network structure. Therefore, the implementation of both management types in the same landscape helps to maintain high species and interaction diversity.

The conservation of forest biodiversity is increasingly relying on forest landscapes managed for timber production. A precondition for successful biodiversity conservation in intensively managed landscapes is a good understanding of habitat- and landscape-level drivers of species diversity. In this study, we investigated the effects of habitat characteristics and landscape context on the species richness and composition of butterflies in temperate forest landscapes routinely managed by clear-cutting. Our focus was on forest-dependent species. Even though about a quarter of the entire butterfly fauna in Europe are associated with forest habitats, the drivers of their diversity are poorly known. We used data from an unprecedentedly extensive butterfly survey, conducted in more than 400 sites distributed across all major forest types in Estonia (Northern Europe). Our data indicate that, generally, forests harvested for timber production remain suitable as habitats for forest butterflies: across the study sites, we recorded almost the full complement of their total regional species richness. By far the most influential driver of local butterfly species richness in such forests appears to be the proportion of forest cover in the surrounding landscape. The species richness of forest butterflies starts to show signs of decline at remarkably high levels of forest cover in the landscape. Surprisingly, landscape-scale forest heterogeneity around study sites had no discernible effect on local species richness, the pattern plausibly resulting from low mobility of forest butterflies. The most important habitat-scale predictor of butterfly species richness was soil moisture, with butterfly communities being most species-rich in forests on soils of intermediate moisture. Different forest types contribute to the regional species pool of forest butterflies in a complementary manner. No single forest type alone provides habitat for the entire species pool: peaks of abundance of different species are distributed across multiple forest types. Accordingly, a substantial part of the variation in species assemblages could be attributed to characteristic soil conditions (moisture and pH) of different forest types. Our findings imply that both the extent and heterogeneity of forest landscapes are important for maintaining the diversity of forest butterflies at the landscape scale.

Forests managed by clear-cutting, rich in open spaces, provide alternative habitat for many grassland butterfly species in boreal and temperate environments. We have recently shown that local butterfly assemblages in forest openings are shaped by environmental filtering rather than dispersal limitation. However, at the level of individual movements, forest is known to form dispersal barrier for open-habitat butterfliesroutine movements associated with resource exploitation do not result in dispersal in such landscapes. Typically, clear-cuts are varyingly surrounded by forest, meaning that movements between them and colonisation of newly created clear-cuts often require crossing hard boundaries between open habitat and matrix. Butterflies making such dispersal decisions may not be a random sample of individuals from the population. We used this semi-experimental landscape configuration with distinct habitat patches and matrix to examine if dispersal decisions are associated with special morphological phenotypes. Contrary to expectations, we found no significant associations between flight morphology and realised dispersal decisionscolonisers of isolated clear-cuts (fully surrounded by forest) did not differ from individuals of surrounding non-isolated habitats in any of measured wing traits. The differences in flight morphology between contrasting sites were negligible in all species and there were no consistent differences between males and females. As a possible interpretation, we link our findings to frequent, deterministic events of habitat loss and formation in forests managed by clear-cutting which may imply that virtually all phenotypes in such landscapes represent dispersal phenotypes.

Evaluating ecological processes that assemble local animal communities from available species pools has remained a challenging task. At a time of drastic decline of natural and seminatural grasslands, contemporary production forests provide various novel types of open spaces (clear-cuts, power line corridors, etc.) that are potentially suitable habitats for many grassland species, such as butterflies. On the other hand, grassland butterflies are known to perceive forest as a dispersal barrier, potentially limiting the utility of such alternative habitats. We evaluated the role of dispersal limitation in structuring local butterfly assemblages in conventionally managed forest landscapes in which clear-cutting generates varyingly isolated transient open habitats within the forest matrix. We compared butterfly species richness and composition in clear-cuts at opposite ends of a connectivity gradient: sites completely surrounded by forest (isolated clear-cuts) vs. sites connected to the network of other forest clearings by open corridors (non-isolated clear-cuts). We found only a slight difference in the species richness between isolated and non-isolated clear-cuts, both when all open-habitat species and when the subset of grassland species was compared. The frequencies of individual butterfly species in isolated and non-isolated sites were strongly correlated, regardless of their presumed dispersal ability. Our results indicate that, in large areas of production forests in Northern Europe, the formation of local butterfly assemblages is not significantly limited by dispersal. This study contributes to emerging evidence that open spaces in managed forest landscapes can be regarded as alternative habitat for a substantial share of species traditionally considered to be associated with grasslands.

Contemporary forest landscapes in boreal and temperate environments, harvested by clear-cutting, contain various novel types of open spaces which are potentially suitable for species inhabiting natural or semi-natural open habitats. However, systematic analyses identifying the share of the regional species pool that can take advantage of this opportunity are missing. We assessed the importance of such forest openings for open-habitat butterflies in Estonia in Northern Europe by comparing butterfly species richness and composition in forest clear-cuts with their regional species pool. The species richness of butterflies in clear-cuts appeared to be remarkably high: we recorded altogether 81% of the total regional species pool across the study sites. Clear-cuts were inhabited by a very high share (79%) of regionally occurring grassland species, as well as nearly complete sets of open-habitat generalists and forest species. Redundancy analysis showed that clear-cuts in forests with different environmental characteristics harbour distinct butterfly assemblages, their contribution to the butterfly fauna in forest landscapes being thus complementary. This as well as several other lines of evidence indicate that most butterfly species can form resident populations in harvested forest landscapes. Our findings demonstrate that considering novel types of forest openings as 'temporary meadows' can substantially improve the conservation prospects for butterflies and other organisms that have traditionally been considered to inhabit grasslands and other open habitats in agricultural landscapes. Human-altered ecosystems may thus prove to be a viable alternative where restoring or maintaining natural and semi-natural habitats is impossible. (C) 2016 Elsevier B.V. All rights reserved.