Abstract Nests built by vertebrates constitute diverse microhabitats that are inhabited by many taxa other than their owners. Hence, vertebrate nests can be important hubs of local biodiversity. Arthropods are the largest group of additional nest users, forming complex networks of interspecific relationships; hence, the distribution of nest‐building animals and the availability of their nests may have a significant impact on local arthropod communities. We investigated factors that may explain differences in macroarthropod communities in ephemeral nests of Wood Warblers, Phylloscopus sibilatrix (Bechstein, 1793), a declining ground‐nesting songbird, and compared them to leaf litter nearby. In 2019–2020, we collected 168 warbler nests and 45 leaf litter samples in the primeval stands of the Białowieża Forest (Poland). From nests and litter samples, we extracted, respectively, 11759 and 349 macroarthropod specimens, which represented 183 and 70 species. The composition of nest‐dwelling macroarthropods varied within and between years, and between the warbler's nesting stages, and with time since nest abandonment by the birds. Habitat type, nest size and material composition poorly explained differences in the nests' macroarthropod communities. Compared to leaf litter in the surrounding environment, warbler nests hosted distinctive, more abundant and slightly more diverse macroarthropod communities. Our findings are likely to be relevant to a wide range of bird and mammal nests. Thus, the widespread decline of nest‐building vertebrates might reduce the availability of nest resources, potentially posing a previously overlooked threat to invertebrate conservation.

Abstract Land‐use change and elevational gradients jointly influence biodiversity and species distribution, yet their concurrent effects on arthropods in the Indian Himalayan Region remain largely undocumented. Using spiders as a model taxon, this study assesses the parallel influences of elevation (1500–4500‐m at 500‐m intervals) and land‐use categories viz. forests, agricultural lands and human‐dominated regions on spider functional diversity in a North‐Western Himalayan landscape. The results show non‐general patterns, with significant discrepancies in managed habitats compared to forests, and a higher abundance of synanthropic species in human‐dominated regions. Directional shifts in functional traits are associated with elevational change, with the transition between 3000 and 3500 m emerging as a critical functional and community threshold for Himalayan spider assemblages. The findings highlight functional variability under simultaneous natural and anthropogenic pressures and raise concerns about habitat homogenization driven by large‐scale agro‐production in climate‐vulnerable Himalayan regions, potentially shifting biodiversity towards new functional regimes.

Abstract The Middle East hosts a high diversity of terrestrial and freshwater biota. However, this biodiversity is under threat from climate change, overexploitation and land‐use change—particularly through irrigated agriculture and urbanization. Biodiversity data for the region remain fragmented and sparse, creating significant knowledge gaps that hinder effective conservation planning. We investigated how land‐use types and water availability influence multiple dimensions of freshwater biodiversity, using Odonata (dragonflies and damselflies) as bioindicators. We analysed 12,770 occurrence records for 144 Odonata species across the Middle East to estimate taxonomic (TD), phylogenetic (PD) and functional diversity (FD), applying incidence‐based Hill numbers with rarefaction and extrapolation. Our results show that the availability of long‐lasting water bodies significantly enhances all facets of Odonata diversity, underscoring the importance of stable aquatic habitats. Urbanization had consistently negative effects across all biodiversity dimensions, likely due to the limited availability of suitable aquatic and terrestrial habitats. Agricultural land use had a positive effect on TD and PD, possibly explained by the creation of artificial irrigation water bodies, but showed no effect on FD—suggesting a homogenization of functional traits and the dominance of species with similar ecological roles. While agricultural expansion may enhance regional biodiversity, its potential to drive functional homogenization raises concerns about ecosystem resilience. Moreover, its long‐term sustainability is uncertain due to accelerating groundwater depletion and salinization across the region. These findings highlight the urgent need for region‐specific research and integrated water management strategies to balance development with biodiversity conservation in arid regions.

Abstract Terrestrial insect communities are key components of ecosystems and sensitive indicators of environmental change. We assessed the effects of the 2019 Brumadinho mining disaster on five insect taxa (ants, bees, butterflies, dung beetles and termites) over 2 years, focusing on their seasonal dynamics across 20 sites representing three habitat categories: fragments adjacent to the mudflow, reference sites and legally protected areas. Despite severe habitat loss, insect species richness, seasonal fluctuations in richness, and temporal β‐diversity did not differ significantly among habitat categories. We suggest that this pattern may reflect a resistance of insect communities to tailings deposition, at least in the short term, coupled with their high dispersal ability, potentially driven by metacommunity connectivity and the buffering effect of the surrounding landscape. Protected areas harboured the greatest number of exclusive species, highlighting their role as biodiversity reservoirs within this disturbed region. We also observed clear general seasonal trends, with higher species richness during the wet season for ants, bees, butterflies and dung beetles, whereas termites showed no significant seasonal variation. Seasonal β‐diversity was predominantly driven by species turnover across the five insect taxa. Our findings reveal that, two years after the disaster, insect communities maintained stable richness and β‐diversity, with seasonal dynamics largely unaffected in forests adjacent to the mudflow. These results sustain the need for long‐term, multitaxa insect monitoring to detect potential delayed or subtle ecological impacts of mining disasters.

Abstract Floral and nesting resources are two major components of habitat specialization that drive patterns of bee distribution. However, nesting resources are largely understudied in comparison to floral resources. For nesting, bees are generally thought to prefer nesting in sandy soils, and numerous species are considered sand specialists. With little empirical evidence to date, we aimed to test how soil sand content and floral resource availability interact to affect patterns of bee distribution and whether sand specialist bees predominantly occur in sandy habitats. We set up a carefully designed observational study in Minnesota, USA, across three classes of soil sand content ( N = 28 plots) using a focal prairie plant species ( Dalea purpurea ) that attracts a wide range of bee species and can grow in different soil types. We identified three key results: (1) soil sand content, not floral resource availability, affected patterns of bee distribution; (2) contrary to expectations, sandier sites did not host the highest diversity of bee species; and (3) there was clear evidence of sand specialization for select bee species, but sand specialists were associated with both moderate and high amounts of sand rather than extremely sandy areas. Our findings highlight that soil properties, specifically soil sand content, can be important in driving patterns of bee distribution, specifically sand specialists. Therefore, not factoring soil properties into bee conservation and restoration decisions may limit our effectiveness and ability to support habitat specialists and rarer bee communities.

Abstract European forest wetlands have experienced long‐term declines due to drainage and other human disturbances. Despite their ecological importance, these habitats remain underrepresented in biodiversity assessments, and there is limited empirical evidence to guide effective conservation and rewetting efforts. In a paired design, we investigated how managed versus unmanaged forests affected saproxylic and soil‐inhabiting crane fly communities across three forest habitat types in Denmark: swamps, drainage ditches and dry patches. We collected 6842 crane fly specimens, representing 104 species, across 110 forest plots. Species richness was consistently higher in unmanaged forests, with significant positive effects observed for both saproxylic and soil‐inhabiting species across all habitat types. Soil‐inhabiting species richness was highest in swamps, intermediate in ditches and lowest in dry forest, but not for saproxylic species. Across habitats, saproxylic richness was positively associated with low light availability, and soil‐inhabiting richness with higher soil pH. Soil moisture generally had a positive influence on richness in both groups. Unmanaged swamps also supported distinct species assemblages, including several indicator species and habitat specialists. Our results highlight abandonment of forest management as a key strategy for enhancing biodiversity in temperate broadleaf forest swamps. Conservation efforts should prioritize restoring natural hydrology and protecting old‐growth swamp habitats, in combination with passive management approaches.

Abstract Black flies (simuliids) are an ecologically and medically important group of cosmopolitan insects whose distribution is influenced by climate and landscape changes. This study aimed to analyse diversity, distribution and frequency of simuliid species in the Balkan Peninsula, investigating how their ecological patterns relate to both regional geographic factors and local habitat characteristics. Total of n = 40,733 larvae and pupae (45 taxa) were collected from 256 sites from 2010 to 2021. Localities were categorised by catchment basin, hydro‐ecoregion and predefined watercourse types. Distribution, land use and diversity measures were analysed. Altitude and 19 bioclimatic variables were included as continuous environmental predictors. Simulium ornatum, S. reptans, S. variegatum and S. balcanicum were the most frequent. Overall species richness ranged from 1 to 8 taxa, influenced by bioclimatic factors and land use, with peak richness observed under moderate anthropogenic disturbance. Species replacement was a significant component of beta diversity. Altitude significantly influenced assemblage composition. The key bioclimatic drivers included precipitation during driest/warmest periods and mean temperature of the wettest quarter. Hierarchical clustering identified nine distinct simuliid assemblage groups, confirming altitudinal niche differentiation consistent with Rapoport's elevational rule. Higher altitudes are dominated by the S. variegatum group and the genus Prosimulium, while subg. Wilhelmia was characteristic of lowland sites. Diversity distances between simuliid assemblages were also correlated with geographic distances between sampling sites. This study provides a valuable baseline for understanding the complex spatial and environmental drivers of simuliid diversity in the Balkans, crucial for future ecological and conservation research.

Abstract 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.

Abstract Urbanisation creates environmental filters that reshape species behaviour, distribution and community structure. Ants, ecologically dominant in cities, often thrive under urban conditions; however, how urbanisation influences their community structure and foraging strategies remains poorly understood. We investigated the influence of urbanisation on ant community structure (species abundance, richness, taxonomic and functional composition) and foraging behaviour (food resource preference and discovery time) across a gradient of urbanisation intensity in Recife, a major metropolis in northeastern Brazil. We sampled ants using protein‐ and carbohydrate‐based baits at 22 sites representing varying levels of urbanisation, from low‐density residential areas to highly urbanised centres. A total of 42 ant species were recorded across the gradient. While species abundance and richness remained relatively stable, both taxonomic and functional composition shifted significantly with increasing urbanisation. Specialist “loser” species, such as epigaeic predators and cryptic omnivores, declined in favour of generalist “winner” species, including epigaeic omnivores and leaf‐cutting Attini. Foraging behaviour also responded to urbanisation: ants consistently preferred protein‐rich resources, but this preference was not influenced by urbanisation. However, bait discovery time decreased in highly urbanised sites, suggesting that ants forage more efficiently in structurally simplified habitats. Our findings demonstrate that urbanisation drives biotic homogenisation, favouring generalist ants while excluding specialists, and promotes behavioural adaptations that enhance foraging efficiency. These results provide key insights into how urban ecosystems filter species traits and reshape ecological interactions, highlighting the need to consider both community structure and behavioural plasticity when assessing biodiversity responses to urbanisation.