Traditional grazing is a key management practice in grasslands, yet its effects on arthropod communities depend strongly on timing and habitat conditions. We investigated how grazing influences true bug (Heteroptera) communities in Pannonian saline grasslands, focusing on seasonal variation and vegetation type. We conducted a full-factorial experiment including two vegetation types (dry vs. wet), grazing treatment (grazed vs. ungrazed), and two grazing periods (spring vs. early summer). We hypothesised that grazing effects are (i) stronger in spring than in early summer, (ii) more pronounced in wet than in dry saline vegetation, and (iii) vegetation-dwelling species are more sensitive than ground-dwelling ones.Using generalized linear mixed models and trait-based analyses, we found that grazing effects were context-dependent and primarily driven by changes in the abundance of dominant grass-feeding species. In spring, grazing effects differed between vegetation types, whereas in early summer responses were consistently negative and more closely associated with vegetation characteristics. Overall, grazing reduced abundance by 19%, although responses varied with season and vegetation type, with increased abundance in wet vegetation in spring. Functional traits of vegetation-dwelling true bugs were affected by grazing only in wet saline vegetation in spring. Ground-dwelling communities showed little response.Our results suggest that grazing effects are mediated by both direct (e.g. trampling, incidental ingestion) and indirect (vegetation-mediated) mechanisms, with their relative importance varying seasonally. We highlight that careful timing of grazing and the maintenance of spatial heterogeneity, including ungrazed patches, are crucial for conserving arthropod diversity in grazed grasslands.

Abstract Sustainable management of pastoral landscapes is essential for conserving steppe biodiversity and preventing desertification. In the arid grasslands of Central Asia, livestock overgrazing is a major driver of habitat degradation, yet the ecological responses of terrestrial arthropods, key components of these ecosystems, remain poorly understood. We tested how cessation of domestic grazing affects beetle assemblages by comparing traditionally grazed sites with sites ungrazed for short (<5 years) and long (>10 years) periods in western Mongolia. In addition to composition, we assessed responses of beetle species by their functional traits such as body size, dispersal mode and trophic guild. In total, 986 individuals representing 106 beetle species were recorded. Community composition differed significantly among all management categories, with the strongest separation between grazed and short‐term cessation sites. On the other hand, functional composition of beetles did not differ between the sites with different ungrazing regimes, although trait‐based analyses revealed that short‐term cessation (<5 years) was associated with large‐bodied species. Our findings suggest that traditional nomadic grazing is associated primarily with shifts in species composition, while functional structure appears comparatively stable and may be shaped by additional environmental factors in Mongolian steppes. Management approaches that favour short‐term grazing cessation or spatially heterogeneous grazing (e.g., rotational or patch grazing) may help maintain habitat heterogeneity and support insect diversity in steppe ecosystems.

Topographic depressions in karst landscapes, called dolines, serve as important microrefugia for biodiversity. However, they may be strongly affected by various anthropogenic disturbances, including forest management, waste dumping, and livestock grazing. Although the effects of grazing on doline vegetation are well documented, far less is known about how grazing intensity influences arthropod communities within these landforms. To study the effects of grazing intensity on arthropods, we applied a multi-taxa approach including spiders (Araneae), true bugs (Hemiptera: Heteroptera), and ants (Hymenoptera: Formicidae) as bioindicators. We selected 18 doline bottoms and their adjacent plateaus in the Aggtelek Karst, Hungary, and sampled them over two consecutive years - with grazing present in one year and excluded in the other, the latter serving as a control. We used structural equation models (SEMs) to assess how habitat type (doline vs. plateau) - which reflects associated differences in microclimate and vegetation characteristics - together with grazing intensity influenced arthropod abundance and diversity. The SEMs showed that in the control year, habitat-related differences between dolines and plateaus were clearly reflected in the diversity patterns of all three arthropod groups, with higher species richness and abundance in dolines. Grazing partially overrode this pattern through both direct and indirect pathways, although the extent and underlying mechanisms differed among taxa. Our results demonstrate that habitat type, vegetation height, and grazing intensity interactively shape arthropod diversity in karst landscapes. Appropriately managed grazing may help maintain the arthropod biodiversity of these microrefugia and should therefore be considered in future conservation planning.

Habitat fragmentation has far-reaching negative impacts on the environment, resulting in biodiversity loss, soil quality degradation and alteration of water availability. In addition, fragmentation can disrupt ecological processes, potentially facilitating the establishment and spread of invasive plants, which can further harm native arthropod communities and alter their ecosystem dynamics. However, the exact nature of these impacts may vary depending on local conditions. We investigated the impact of fragmentation and milkweed invasion on invertebrate communities in sandy grasslands of forest-steppe habitats in Hungary. We selected 30 grasslands in forest-steppe fragments, varying in size (0.2 to 8.7 ha) and connectivity (Hanski’s connectivity index: 0 to 705). We sampled ground-dwelling arthropods, mainly herbivores (true bugs) and predators (spiders), with pitfall traps and pollinators (wild bees) by direct observations along transects in invaded vs. non-invaded patches (min. of 500 m2) of each fragment. We considered arthropod species’ body size (all groups), dispersal ability and feeding (herbivores and predators) and nesting location and social habit (wild bee) traits in our analyses. In non-invaded patches, the number of monophagous herbivores showed an increasing trend, whereas in invaded fragments, there were more polyphagous individuals with increasing connectivity and fragment size. The dispersal ability of predators was lower as connectivity increased in non-invaded patches but higher in patches invaded by milkweed. We found more ground nesting bees in the invaded patches of small fragments than in large fragments, however, we did not find a significant effect in non-invaded patches. In summary, we often found interacting effects of the studied variables, fragmentation and invasions, generally modifying each other’s effect by filtering for opposite trait levels. The primary objective of restoration projects should be restoring habitat of appropriate size and connectivity and eradicating invasive species while concurrently supporting the revival of native species and their ecological relationships. It is essential to employ adaptive management techniques, including continuous monitoring, to effectively tackle the interaction between fragmentation, invasion, and the preservation of biodiversity.

Winter-active ground-dwelling spiders and ground beetles mainly inhabit non-crop habitats (e.g., grasslands and forests) with complex-structured vegetation and stable microclimates. In spring, they migrate from non-crop habitats into crop fields, contributing to pest control. Nowadays, there is an increasing number of solar parks in agricultural landscapes. However, the role of solar parks as habitats for winter-active ground-dwelling spiders and ground beetles and thus their potential contribution to pest control has not been studied yet. We investigated how different habitat types (i.e., forest, grassland, habitat between and under solar panels and abandoned farmland) are associated with variation in microclimatic conditions (i.e., air temperature and humidity) and with the diversity of winter-active ground-dwelling spiders and ground beetles across 50 sites in western Hungary. Using pitfall traps, we collected 957 ground-dwelling spiders belonging to 69 species and 327 ground beetles belonging to 40 species. We recorded microclimatic conditions using data loggers simultaneously with arthropod sampling. We showed that patterns in arthropod assemblages likely reflect differences in microclimatic conditions across habitat types. Solar parks hosted species of different habitats (e.g., forest, grassland, wetland) with a relatively strong preference for humidity. Solar parks also supported a high abundance of agrobiont ground-dwelling spiders (i.e., species dominant in agroecosystems). In contrast, grasslands and abandoned farmlands exhibited the most extreme microclimatic conditions, supporting mainly dry-habitat species. Our results demonstrate for the first time that solar parks can serve heterogeneous habitats for diverse assemblages of winter-active ground-dwelling spiders and ground beetles and may positively contribute to biocontrol and biodiversity conservation.

Europe's rural landscapes, shaped over millennia, support high biodiversity but often have lower living standards than urban areas, potentially leading to social and environmental injustice. Here we studied biodiversity and socioeconomic settings in Central and Eastern European villages across landscape complexity and urbanization gradients. We surveyed the biodiversity of villages by sampling nine taxonomic groups, including plants, arthropods and birds. We found 15% lower multitrophic diversity in villages in agricultural than in forest-dominated landscapes. City vicinity enhanced human well-being (estimated with Better Life Index) but did not affect biodiversity despite a larger human footprint. In agglomerated villages in forest-dominated landscapes, biodiversity was high, with higher Better Life Index and footprint metrics, suggesting associations between biodiversity, socioeconomic status and, thus, environmental injustice. Our results show the high socioecological value of maintaining or restoring landscape complexity around villages and their green infrastructure, requiring top-down incentives and bottom-up initiatives.

Forest plantations, often consisting of non-native tree species, are widespread globally, including the Great Hungarian Plain at the western edge of the Eurasian Forest Steppe zone. Protecting the isolated remnant habitats alone is insufficient to maintain the biodiversity within production landscapes. Linear landscape elements (LLE), such as road verges, can serve as corridors and refuges for species, though their benefits may be limited. To assess the conservation value of dirt road verges between pine plantations, we compared their orthopteran communities with those of natural forest-steppe fragments and extensive pastures as reference habitats. We hypothesized similar conservation value across habitats but expected differences in species composition. We found no significant differences in species richness, abundance, functional diversity, or Grasshopper Conservation Indices between habitats, indicating comparable conservation value. However, species composition was more similar between forest-steppe and road verges than between pastures and road verges. Road verges also supported more small-bodied, low-dispersal orthopterans than pastures. We concluded that dirt road verges between pine plantations sustain high-quality habitat and landscape functional connectivity, conserving various grasshopper species, including sensitive and range-restricted species. We suggest that the verges of unpaved, low-traffic, and irregularly managed dirt roads should receive more attention in efforts to enhance the green infrastructure of fragmented landscapes. These road verges, especially those between plantations, may also play a role in forest-steppe restoration and should be considered in related planning efforts.

Invasive plants can fundamentally impact ecosystems. As arthropods play prominent roles in ecosystem functioning via their food webs, understanding how plant invasion affects arthropod communities is essential. We studied the impact of the invasive grass (Sporobolus cryptandrus) on arthropods (ground beetles, orthopterans, spiders and true bugs) across three habitat types in Hungary: forest steppe, open sand grassland and meadow steppe. We compared the species composition of arthropod communities and the abundance of species of conservation interest between invaded and control plots. We also identified species indicative of either control or invaded plots. Additionally, we analysed the species richness and abundance of arthropod groups along a gradient of the invader density (low, medium, high and control). We found that species composition between invaded and control plots only differed for vegetation-dwelling true bugs and orthopterans, with several species indicative of control plots. Their species richness and/or abundance decreased with increasing Sporobolus cover, varying among habitats. Interestingly, low Sporobolus cover increased the species richness and abundance of ground beetles and the abundance of vegetation-dwelling, primarily web-building spiders. However, the conservation value of true bug, grasshopper and ground beetle species was reduced in invaded sites compared to control sites. We conclude that low Sporobolus cover can temporarily increase species richness and abundance of some arthropod taxa, but this effect is likely short-lived before Sporobolus rapidly gains dominance due to its fast spreading rate. Ultimately, Sporobolus invasion can reduce arthropod diversity, particularly affecting species of high conservation value.

A kaszálás az egyik legelterjedtebb gyepkezelési módszer Európában, mely megfelelően végezve alkalmas számos gyeptípus magas diverzitásának megőrzésére. A nagy területeken, rövid idő alatt végzett kaszálás az ízeltlábúak jelentős direkt mortalitását okozza, emellett csökkenti a gyep mikrohabitat-diverzitását, homogenizálja a mikroklimatikus viszonyokat, mely negatív hatással van az ízeltlábúakra. Kutatásunk célja, hogy a kaszálókon, részben az ízeltlábú-fauna megőrzése miatt kialakított búvósávok természetvédelmi hatékonyságát feltárjuk. Vizsgálatunk során fűháló és talajcsapdák segítségével gyűjtött mintákból faji szintig meghatároztuk az egyenesszárnyúakat, poloskákat, futóbogarakat és a pókokat. A fajszám- és abundanciaadatokat kevert lineáris modellek segítségével értékeltük. A kaszálás alól kizárt területeken jelentősen magasabb ízeltlábú-fajszámot és abundanciát mutattunk ki, mint a kaszált területeken, mely hatások a növényzeten élő, elsősorban herbivór ízeltlábúak esetén erősebbek voltak, mint a talajfelszíni ragadozók esetén. Eredményeink azt bizonyítják, hogy a kaszálatlan búvósávok magas denzitású és diverz ízeltlábú-közösségeknek adnak otthont, ezáltal kulcsfontosságú szerepet játszanak a gyepi ízeltlábúak megőrzésében.

Drainage ditches play a key role in the conservation of fragmented landscapes by providing refuge sites and secondary habitats for many terrestrial and aquatic organisms across various taxa. Species richness of ditches can exceed that of adjacent natural habitats, but here, we looked further and assessed the role of drainage ditches in shaping the community structure of true bugs aiming to better estimate ditches’ conservation value from the point of their species and trait composition. We tested the effects of the ditch substrate (saline, sandy or fen), landscape matrix (agrarian or grassland) and vegetation (species richness of all plants and invasive plants, and abundance of woody plants) on the true bug communities of 60 drainage ditches in the lowland of East-Central Europe. We found that substrate and landscape matrix contributed the most in determining true bug communities. Based on species composition, different substrates and landscape matrix types had distinct communities, but the trait composition showed differentiation according to the landscape matrix in saline habitats only. The trait composition in true bug communities was more diverse in grassland ditches than in agrarian ones, which hosted more habitat generalists associated with invasive vegetation. We concluded that a pronounced gradient in habitat stress, originating in substrate salinity and aridity, causes the differentiation of the true bug communities based on their trait composition. Additionally, intense habitat stress increases the number of habitat specialists and the conservation value of a drainage ditch.

Vast grassland areas disappear due to abandonment, conversion to arable fields or urban areas. Consequently, grassland species have declined dramatically during and since the last century. The majority of remaining European grasslands are managed, many of them by mowing, which, in general, decreases arthropods' abundance and species richness. Here, we aimed to study the effects of width and proportion of refuge areas on local abundance and richness of arthropods in hay meadows. Within a ca. 4000 ha semi-natural grassland area of the Great Hungarian Plain, we established refuge strips of different widths (3 and 9 m) and proportion of total field area (10 and 25%) following a randomised block design with six replicates per treatment. We studied five arthropod groups (grasshoppers, true bugs, carabids and ground-dwelling and vegetation-dwelling spiders), which we sampled 2 weeks after mowing by sweep netting and pitfall traps. Uncut strips were warmer and moister than the mown areas. The effects of refuge strips and their arrangement were stronger on the vegetation-dwelling than on ground-dwelling arthropods, although all taxa were affected in some way. We found more true bugs in mown areas between narrow strips than between wide strips. The interaction effect of width and proportion of refuge strips on the abundance of grasshoppers, ground-dwelling spiders and species richness of carabids showed that wider strips are more beneficial if their proportion is low and narrow strips are more beneficial with high proportion. Synthesis and applications: Our findings provide evidence that uncut refuge strips can harbour diverse and abundant arthropod assemblages in hay meadows and mitigate the adverse effects of uniformly executed mowing on arthropods. Modifying attributes and considering farming practices, wide strips with a low (10%) proportion of total field area seem optimal for both conservation and practitioners. Our findings provide evidence that uncut refuge strips can harbour diverse and abundant arthropod assemblages in hay meadows and mitigate the adverse effects of uniformly executed mowing on arthropods. Modifying attributes and considering farming practices, wide strips with a low (10%) proportion of total field area seem optimal for both conservation and practitioners.image

Grassland ecosystems undergo dramatic habitat loss and fragmentation worldwide due to agricultural expansion and intensification. Among different taxonomic groups, grassland arthropods are particularly sensitive to this process and, therefore, are exposed to considerable risk. Although many studies focus on land use impacts on arthropod diversity, these mostly consider taxonomic diversity and neglect trait‐mediated functional responses. However, studying functional diversity often provides more accurate insights into ecosystem processes. Here, we assessed the effect of fragment size and connectivity on the functional composition (community‐weighted mean trait values) and diversity (Rao's quadratic entropy) of two diverse and abundant arthropod groups: spiders and true bugs. We assigned functional traits for more than 300 species collected from 30 sandy steppe (forest‐steppes) and 30 loess steppe fragments (kurgans) in the southern part of the Hungarian Great Plain. Functional responses to fragmentation were observed for spiders in forest‐steppes and for true bugs in kurgans. We found higher functional diversity in better‐connected fragments for spiders and in small fragments for both groups. We collected small, humidity‐preferring and web‐building spiders in small fragments, and there were more ballooning spiders with moist habitat preferences in well‐connected fragments. Furthermore, increasing grassland connectivity resulted in a significantly higher proportion of polyphagous and humidity‐preferring individuals in the true bug communities. Our results highlight the importance of small grassland fragments in maintaining high arthropod functional diversity. Even small fragments in a well‐connected grassland network can promote ecosystem functioning and associated services within human‐dominated landscapes.

Plant invasion and habitat fragmentation have a detrimental effect on biodiversity in nearly all types of ecosystems. We compared the direct and indirect effects of the invasion of the common milkweed (Asclepias syriaca) on biodiversity patterns in different-sized Hungarian forest-steppe fragments. We assessed vegetation structure, measured temperature and soil moisture, and studied organisms with different ecological roles in invaded and non-invaded sites of fragments: plants, bees, butterflies, flower-visiting wasps, flies, true bugs, and spiders. Temperature and soil moisture were lower in invaded than in non-invaded area. Milkweed had a positive effect on plant species richness and flower abundance. In contrast, we mainly found indirect effects of invasion on arthropods through alteration of physical habitat characteristics and food resources. Pollinators were positively affected by native flowers, thus, milkweed indirectly supported pollinators. Similarly, we found higher species richness of herbivores in invaded sites than control sites, as species richness of true bugs also increased with increasing plant species richness. Predators were positively affected by complex vegetation structure, higher soil moisture and lower temperature. Furthermore, increasing fragment size had a strong negative effect on spider species richness of non-invaded sites, but no effect in invaded sites. Especially, grassland specialist spiders were more sensitive to fragment size than generalists, whereas generalist spider species rather profited from invasion. Although milkweed invades natural areas, we did not identify strong negative effects of its presence on the diversity of the grassland biota. However, the supportive effect of milkweed on a few generalist species homogenises the communities. The rate of invasion might increase with increasing fragmentation, therefore we recommend eliminating invasive plants from small habitat fragments to preserve the native biota. Focusing also on generalist species and revealing the indirect effects of invasions are essential for understanding the invasion mechanisms and would support restoration efforts.

Livestock grazing is one of the most common management practices for grasslands and can greatly affect their biodiversity. However, arthropod diversity response patterns to grazing regimes are difficult to predict. We conducted a short-term grazing exclusion experiment in traditionally managed alkali grasslands in Hungary to investigate differences between grazed and ungrazed vegetation for different arthropod groups. The experiment was laid out in a full factorial design, with twelve 50 x 100 m short-term grazing exclosures in vegetation types with high (alkali wet meadow) and low productivity (alkali steppe). We sampled ground beetles and spiders with pitfall traps and true hoppers by sweep netting. We used vegetation type (wet meadow vs dry steppe), man-agement (grazed vs ungrazed) and their interaction as fixed effects in mixed models. We found higher species richness and activity density of spiders and ground beetles in the more productive wet meadow vegetation, where the community structure of each arthropod group also shifted toward hygrophilous species. Significant interactions between vegetation type and management indicated a dependence of management effects on vegetation types: arthropod community structure shifted towards hygrophilous species in ungrazed meadows, but not in ungrazed steppe sites. True hopper abundance was higher in grazed meadow sites, but lower in grazed steppe sites, compared to ungrazed sites. True hopper community structure shifted toward generalist herbivores in ungrazed sites, regardless of vegetation type. We concluded that vegetation types determine arthropod communities and modulate the effects of grazing on arthropods. Our results suggest that moderate disturbance from low-intensity grazing has a positive or neutral effect in wetter, more productive vegetation, but a negative or neutral effect in drier, less productive vegetation, depending on the arthropod group. Herbivorous insects that dwell on plants are particularly affected by management because they are more susceptible to direct impacts, such as unintentional predation by grazing cattle, and because of asymmetrical competition between mammalian and insect herbivores.

Proper grazing management of grasslands ensures both economic sustainability and biodiversity conservation. However, the response patterns of arthropod diversity to grazing regimes are poorly predictable. To explore the responses of various arthropod groups to grazing, a short-term grazing exclusion experiment was performed in traditionally managed alkali grasslands in Hungary. The experiment was formed in a full factorial design, establishing twelve 50×100 m fenced grazing exclusions in high- (alkali wet meadow) and low-productivity (alkali steppe) vegetation types. We sampled ground beetles and spiders by pitfall trapping and true hoppers by sweep-netting at two sites both in the exclusions and the nearby grazed areas (N=48). To reveal the responses of arthropods to grazing, we applied mixed-effects models and the indicator species approach. In the models, species richness, abundance, and community weighted mean trait values of each arthropod group were used as response variables. Vegetation type (wet meadow vs. dry steppe), grazing treatment (grazed vs. fenced) and their interaction were used as fixed effects. In the more productive wet meadow vegetation, the species richness and activity density of spiders and ground beetles were higher and the community structure of each arthropod group was shifted toward hygrophilous species, compared to dry steppe vegetation. Significant interacting effects of vegetation type and grazing treatment suggested dependencies of grazing effects on vegetation types: the community structure of arthropods was shifted towards xerophilous species in the grazed meadow, but not in the grazed steppe sites. The abundance of true hoppers was higher in grazed meadow sites, but lower in grazed steppe sites, compared to ungrazed sites. True hopper community structure was shifted toward generalist herbivores in ungrazed sites, irrespectively of vegetation types. We concluded that vegetation types determine arthropod communities and modulate the effect of grazing on arthropods. Our results suggest that a moderate disturbance by low-intensity grazing is positive or neutral in more humid and productive vegetation, but negative or neutral in dry, less productive vegetation, depending on arthropod groups. Plant-dwelling herbivorous insects are particularly affected by grazing as they are more susceptible to direct effects, e.g. unintentional predation, and because of the asymmetrical competition between livestock and insect herbivores.

As a consequence of agricultural intensification and habitat fragmentation since the mid-20th century, biological diversity has declined considerably throughout the world, particularly in Europe. We assessed how habitat and landscape-scale heterogeneity, such as variation in fragment size (small vs. large) and landscape configuration (measured as connectivity index), affect plant and arthropod diversity. We focused on arthropods with different feeding behaviour and mobility, spiders (predators, moderate dispersal), true bugs (mainly herbivores and omnivores with moderate dispersal), wild bees (pollinators with good dispersal abilities), and wasps (pollinators, omnivores with good dispersal abilities). We studied 60 dry grassland fragments in the same region (Hungarian Great Plain); 30 fragments were represented by the grassland component of forest-steppe stands, and 30 were situated on burial mounds (kurgans). Forest-steppes are mosaics of dry grasslands with small forests in a matrix of plantation forests. Kurgans are ancient burial mounds with moderately disturbed grasslands surrounded by agricultural fields. The size of fragments ranged between 0.16–6.88 ha (small: 0.16–0.48 ha, large: 0.93–6.88 ha) for forest-steppes and 0.01–0.44 ha (small: 0.01–0.10 ha and large: 0.20–0.44 ha) for kurgans. Fragments also represented an isolation gradient from almost cleared and homogenous landscapes, to landscapes with relatively high compositional heterogeneity. Fragment size, connectivity, and their interaction affected specialist and generalist species abundances of forest-steppes and kurgans. Large fragments had higher species richness of ground-dwelling spiders, and the effect of connectivity was more strongly positive for specialist arthropods and more strongly negative for generalists in large than in small fragments. However, we also found a strong positive impact of connectivity for generalist plants in small kurgans in contrast to larger ones. We conclude that besides the well-known effect of enhancing habitat quality, increasing connectivity between fragments by restoring natural and semi-natural habitat patches would help to maintain grassland biodiversity.

Drainage canals are widespread components of agricultural landscapes. Although canals have greatly contributed to biodiversity loss by desiccating wetlands, they have recently attracted conservation attention due to their potential to function as refugia for native species in intensively managed landscapes. However, their conservation role in complex landscapes composed of agricultural fields and desiccated but otherwise untransformed, semi-natural habitats, on which canals still pose a heavy burden, is unknown. Improved understanding of drainage canals and related biodiversity in these landscapes could help unlock their potential and support synergistic land management for nature conservation and water resource management. We applied a multi-taxon approach, including plants, butterflies, true bugs, spiders and birds, to (a) assess the conservation value of drainage canals with temporary water cover in a heavily drained European lowland region, (b) to test landscape-level and local canal parameters for aiding prioritization among canals and (c) to propose a reconciliation-based management framework that suits the interest of all stakeholders. We found that drainage canals and their banks concentrate more species across most taxa than semi-natural, mostly grassland habitats, possibly due to micro-environmental heterogeneity and the absence of low-intensity annual management compared to grasslands. Canals traversing semi-natural grasslands concentrate particularly high numbers of native species, but agricultural canals also support remarkable species richness. However, agricultural canals are important dispersal corridors for non-native invasive plants, which may negatively affect native biodiversity. Canal size has little effect on biodiversity, but habitat stress is an important determinant. The higher the stress (due to sandiness and salinity), the higher the added value of canals to landscape-wide biodiversity. Synthesis and applications. We show that drainage canals can harbour high biodiversity and should therefore be recognized as important novel ecosystems with high conservation value, even when cutting through semi-natural grassland habitats. Canals have previously been considered detrimental to nature conservation due to their association with loss of wetlands. However, by reducing water loss with reversible obstructions, controlling invasive species and applying specific conservation measures, they may be turned into conservation allies without compromising long-term interests of water management and agricultural land use.

Disentangling the effects of different landscape and local attributes on the biota of habitat patches is often challenging. In Central European forest-steppe ecosystems the high number of forest fragments and the relatively homogenous matrix between them offer the opportunity to disentangle the effects of habitat size and landscape structure (both landscape composition and landscape configuration) on plant and arthropod biodiversity. We selected 40 forest fragments: 20 forest fragments in extensive, dry, sandy forest-steppe region and 20 fragments in a mesic forest-steppe region of Hungary. We classified the detected plant and arthropod species according to their habitat association as forest specialist species or open habitat species. We then tested the effect of fragment size, landscape composition, and landscape configuration on their species richness and abundances. We found that increasing forest fragment size, forest habitat amount, and forest edge length had in general positive effects on forest spider abundance, but negative on open-habitat arthropod abundances and plant species richness, varying a little among the studied taxa. Most interestingly, the effects of fragment size were often moderated by both landscape composition and landscape configuration, as well as habitat association of species. The fragment size effect was more pronounced in landscapes with low forest habitat amount having positive effects on forest spiders and negative effects on open-habitat plants. An effective conservation strategy should take into account not only the presence of forest fragments, but also the size and configuration as well as the connectivity of forest fragments, to maximize diversity benefits of forest patches.

Species can survive periods of unfavorable conditions in small areas that are protected from climate-related disturbances, such as increasing temperature and severe drought. These areas are known as “microrefugia” and are increasingly recognized by conservationists. Although some studies suggest that the in situ survival of invertebrate species may be mediated by topographically complex environments, there is little information about the main environmental factors that drive species distributions within such areas. Here, we investigate the spatial patterns and species trait composition (moisture preference, body size, dispersal capacity, and feeding habit) of five groups of ground-dwelling arthropods—spiders, woodlice, ants, ground beetles, and rove beetles—in topographic depressions (i.e., “solution dolines” or “solution sinkholes”) and on the surrounding plateau within a forested karst landscape and analyze the microhabitat conditions that affect these arthropod assemblages. We found that dolines have the capacity to maintain characteristic arthropod assemblages—including species that may be particularly vulnerable to climate change (e.g., species associated with moist habitats)—and thus, they may contribute to the landscape-scale biodiversity of karst landscapes. We also found that doline bottoms have the potential to maintain permanently moist conditions not only in spring and autumn but also during drier periods of the year. This ability of dolines may indicate the presence of potential hydrologic microrefugia. Furthermore, dolines displayed specific sets of species traits (e.g., more small-bodied spiders, more carnivorous ground beetles, and more rove beetles with high dispersal capacity occurred in dolines than on the plateau), highlighting that they may facilitate the persistence of some species and traits that are purged from the surrounding landscape. Future studies may reveal the long-term ecological consequences of different climatic and anthropogenic factors on the distribution and functional traits of arthropod taxa within microrefugia and on the refugial capacity of these safe havens under a warming climate.