Agricultural intensification has a strong impact on arthropod diversity, yet predators such as spiders provide key ecosystem services through natural pest regulation. Understanding how local and landscape factors shape spider assemblages throughout the season is essential for designing effective agro-ecological infrastructures that can sustain their services in crop systems. We investigated ground-dwelling spider communities in Belgian winter cereal fields and their margins. Pitfall traps were used across seasons to assess the effects of habitat (field vs. margin), surrounding crop cover, and seasonal dynamics on spider richness, activity-density, and community structure. Results show that spider activity-densities were consistently higher in margins than in fields, whereas species richness showed no significant differences between these habitats. Significant seasonal variations were detected on both spider richness and abundance. The landscape effect of the annual crop cover was context dependent, showing seasonal and species-specific patterns and even positive associations in autumn. Seasonal shifts also reflected life stage and sex-specific phenologies. This study reveals that spider communities in Belgian cereal systems are shaped by interacting local, landscape, and seasonal factors. Margins mainly act as refuges that bolster spider numbers rather than species pools, while the influence of the surrounding landscape depends on the season and the species identity. These findings highlight the need to incorporate temporal and biological context when designing margins and other agro-ecological infrastructures to support natural pest regulation providers such as spiders.

Abstract Addressing biodiversity loss requires knowing how different living beings are spatially distributed. For hyper‐diverse groups such as spiders, biogeographic dispersal‐related processes tend to be the main factor driving diversity patterns at large spatial scales, while the relevance of ecological filtering (species sorting) may increase at lower spatial scales. To determine how spider diversity and structure are shaped at local spatial scales, we sampled spider communities using a standardized optimized protocol and assessed habitat heterogeneity across 10 Mediterranean forest plots in the Northeastern Iberian Peninsula. We compared the spiders' composition and structure among forest types and across vegetation layers using generalized linear models and linear mixed models for assessing patterns of alpha‐diversity and constrained ordination analyses for understanding beta‐diversity patterns. Across forests, habitat heterogeneity was the only significant driver for structuring alpha‐ and beta‐diversity, and the geographic and climate distance explained a low variance of the models. Pine forests were separated in the redundancy analyses from holm oak and deciduous forests because a lower vegetation cover characterized the latter. Lineal models of alpha‐diversity at the microhabitat scale only showed significant negative tendencies for the rock cover. Beta‐diversity across vegetation layers within a plot and across forests appears to be influenced primarily by habitat heterogeneity, particularly by the presence of herbaceous and low shrub cover. Our results highlight the importance of species sorting over biogeography and climatic variables in shaping spider diversity patterns at the local scale. They also indicate that a mosaic of habitat structure within and between forest types is a significant driver of spider diversity. These findings have implications for assessing spider assemblages—and likely other arthropods—suggesting that a combination of methods capturing microhabitat descriptors is crucial for effective monitoring schemes.

Spiders are a highly diverse group that occupies a wide range of terrestrial microhabitats, from leaf litter to the forest canopy, which has led to the development of numerous collection methods. Yet, there remains a pressing need for standardization in sampling protocols to ensure comparability across spider studies. In this study, we evaluated whether pitfall trap spacing (1 m, 10 m, and 20 m) influences the outcomes of spider sampling campaigns in Neotropical savannas. Pitfall traps were arranged in sets of sixteen, with each set representing one of the three spacing treatments. Nine sampling points were established, each comprising three sets of traps positioned 100 m apart. We collected 2,237 specimens representing 26 families and 76 species or morphospecies. Trap spacing had no significant effect on spider abundance, species richness, or assemblage composition. Community composition was influenced only by vegetation complexity, which explained a modest portion of the variation. Among the most abundant taxa, only Salticidae responded significantly to trap spacing, being more abundant at 20 m, while Leprolochus mucuge showed a weak positive association with vegetation complexity. Together, these findings indicate that spider assemblages in the Cerrado are broadly robust to the trap-spacing distances tested. Based on our results, we suggest practical strategies for standardizing pitfall trap designs. Applying and testing these guidelines across additional biomes will be crucial for refining global standards for arthropod sampling.

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.

Riparian zones in the Brazilian Cerrado are increasingly threatened by agricultural expansion, deforestation, and land-use change, with significant implications for biodiversity conservation. Spiders are ecologically important predators and bioindicators, yet little is known about how they respond to changes in vegetation structure in riparian habitats. This study aims to assess the influence of canopy cover and understory complexity on the diversity, abundance, and composition of understory spider assemblages in riparian zones. We sampled 3260 adult spiders across 30 first- to fourth-order streams in the Cerrado, using standardized beating tray methods, and measured habitat structure variables. Our results showed that canopy cover had a positive effect on spider abundance and species richness, while understory complexity was significantly related only to species richness. Vegetation structure had a limited effect on species composition. Using threshold indicator taxa analysis (TITAN), we identified ecological thresholds for canopy cover between 58 % and 77 %, and 16 spider taxa were classified as indicators of change along this gradient. The study demonstrates that canopy cover is a significant driver of spider diversity and that threshold-based metrics can help identify sensitive points of ecosystem change.Implications for insect conservation: Riparian zones in the Cerrado biome should be prioritized for conservation and restoration, especially where canopy cover has been markedly diminished. Preserving canopy cover above 60 % is likely essential to maintain both the structural integrity and functional dynamics of understory spider assemblages. As reliable bioindicators at species and community levels, spiders can effectively reflect riparian habitat quality. Therefore, conservation strategies ought to encompass restricting deforestation along riparian margins, enforcing buffer-zone regulations and reestablishing native vegetation to enhance habitat complexity. These measures are crucial not only for protecting spider diversity but also for sustaining the ecosystem services they provide, such as natural pest control and trophic regulation at the aquatic–terrestrial interface.

The original study of arthropods in the project”Allmendweiden im Biosphärengebiet Schwarzwald – Insektendiversität, Strukturreichtum und Folgerungen für das Management“was carried out on behalf of the Black Forest Biosphere Reserve Office of the Regional Council of Freiburg and funded by the Foundation Nature Conservation Fund Baden-Württemberg. The common pastures (Allmendweiden) in the Black Forest Biosphere Reserve are located in the montane to subalpine zone in the southern Black Forest. These grassland areas have presumably been used extensively for hundreds of years. Today they are characterised by a structurally rich vegetation of dry or moist mat-grass meadows, dwarf shrub heaths and managed by grazing with different livestock and intensities. The spiders as by-catch in pitfall traps were identified and the (dis)similarities among the spider assemblages of different habitat types within the pastures were analysed as part of a master's thesis by the first author. In 30 plots, representative locations of approximately 2000 m2 within five pasture areas, 180 pitfall traps were placed. Six traps were positioned in two rows, five metres apart, in each plot and operated for a total of 84 days in April, May and June, and August and September 2021. In total, 12536 (9877 adult) spiders representing 149 species were sampled. Among them are two single-specimen records of previously unrecorded species in Baden-Württemberg (Improphantes improbulus (Simon, 1929) and Lathys heterophthalma Kulczyński, 1891) as well as several remarkable species with regard to their conservation status or rarity at least in Baden-Württemberg, such as Peponocranium orbiculatum (O. Pickard-Cambridge, 1882), Pardosa bifasciata (C. L. Koch, 1834), Pardosa nigriceps (Thorell, 1856), Arctosa figurata (Simon, 1876), Pellenes tripunctatus (Walckenaer, 1802) and Talavera thorelli (Kulczyński, 1891). All of them show a clear affinity for xerothermic open habitats.

Drivers of saltmarsh spider assemblages in a coastal lagoon: Implications for biodiversity assessment and habitat management

University campuses are well differentiated places from other urban areas because they are usually built to foster an educational environment, support scientific research and nature conservation. However, few studies have tested their potential benefit for urban biodiversity, which could be especially relevant in understudied hot spots, like the Mediterranean region. Spiders, as top urban predators, play a vital role in ecosystem functioning and serve as bioindicators for certain habitat alterations. Here, we investigated whether university campuses in a Mediterranean city hold higher levels of spider diversity than other non-campus urban areas. To do so, we analyzed abundance and the taxonomic, functional and phylogenetic diversity of ground-dwelling and web-weaving spider communities of three university campuses and three other non-campus urban areas in the city of Granada (Spain). Contrary to our expectations, the results suggest that university campuses harbor similar levels of spider diversity to other urban areas. Furthermore, we identified certain urban features that can significantly influence spider assemblages in cities. The presence of native and reduced maintenance along with specific surface types (i.e., herbaceous, campus buildings, pavement and bare soil) were found to enhance the diversity of the urban ground-dwelling spider communities, while web-weaving species are more susceptible to the distance to the outskirts, university campuses management or landscape coverages (i.e., herbaceous or bare soil). These findings suggest that such features should be considered when designing urban areas to promote urban biodiversity.

Abstract Background Temperate dry grasslands host diverse communities of predatory arthropods, yet their biodiversity is increasingly threatened by habitat degradation following the abandonment of traditional land-use practices. In many regions, restoring such practices is unfeasible or economically unsustainable, highlighting the need for an alternative, cost-effective, and ecologically sound management strategy. Prescribed burning has emerged as a promising tool to reduce accumulated biomass and limit shrub encroachment. However, scattered shrubs can also enhance habitat heterogeneity and buffer arthropods against climate extremes. Despite its growing use, the indirect effects of prescribed burning on invertebrate predators mediated through changes in vegetation structure remain poorly understood. In this study, we examined how prescribed burning, in combination with the presence of common hawthorn shrubs ( Crataegus monogyna Jacq.), affects environmental conditions (i.e., litter cover and plant species richness) and the assemblages of spiders and ground beetles in temperate dry grasslands of the Dunajovice Hills National Nature Monument, Czech Republic. Predatory arthropods were sampled using pitfall traps across six sites, covering four treatments: burnt patches, burnt patches beneath hawthorn, control patches, and control patches beneath hawthorn. Results We recorded 1703 spiders (107 species), 291 ground beetles (35 species), and 126 species of vascular plants. Burnt patches strongly favored xerothermophilous spider species, including several species of conservation concern. In contrast, burnt patches beneath hawthorns supported assemblages of moisture-habitat and shade-tolerant spider species, resulting in higher trait diversity (RaoQ). Control patches supported a greater proportion of shade-tolerant ground beetle species compared to burnt patches. Plant species richness was positively associated with spider species density, independent of treatment. Conclusions Our findings demonstrate that prescribed burning can enhance predatory arthropod biodiversity in temperate dry grasslands, particularly when combined with the retention of scattered hawthorn shrubs. These results are directly applicable to land managers and conservation practitioners working in temperate, nutrient-poor dry grasslands, especially in regions where traditional land-use practices have declined. When applied in late winter, before peak arthropod activity, prescribed burning represents a cost-effective and ecologically viable management strategy for maintaining predatory arthropod diversity in both managed and abandoned dry grasslands.

ABSTRACT While between‐habitat comparisons are commonplace in ecology, we know very little about the changes among species assemblages within habitats. Here we aimed to examine within‐habitat processes in spider assemblages across three elevations in tropical forests, using a design tailored both geographically and methodologically for this purpose. We hypothesised greater within‐habitat βTD (caused by lower connectivity), decreasing body sizes (because of lower temperatures) and less frequent ballooning (due to greater isolation) with increasing elevation. We collected spiders at five within‐habitat (horizontal) distances at each elevation in the Udzungwa Mountains, Tanzania, applying standardised protocols. We assessed differences among assemblages using taxonomic and functional β‐diversity measures and their components. We applied PerMANOVAs to test for different β between elevations, PERMDISP to evaluate within‐habitat variability, exponential and power‐law models to examine within‐habitat distance‐decay, and community weighted values of traits to capture functional patterns for each trait. As predicted, within‐habitat βTD was greater at higher elevations, with stronger distance‐decay relationships (taxonomic and functional). Also, as predicted, high elevation assemblages appeared to show smaller body sizes and lower ballooning frequency. Our results demonstrate the uniqueness of mountain assemblages and that the Udzungwa Mountains, as well as other mountainous areas, should receive increasing conservation attention, as they provide unmissable opportunities to conserve, through small additions or connections, countless small‐range or habitat‐restricted endemic species.

BACKGROUNDSuccessful overwintering habitats are critical for the long‐term survival of biocontrol agents in agricultural landscapes, promoting ecosystem services by preserving beneficial arthropods. Although it is known that predatory arthropods overwinter in leaf litter in fruit orchards, the potential of nonproduction woody vegetation in agricultural landscapes for supporting overwintering spiders is poorly understood.RESULTSWe compared spider assemblages overwintering in leaf litter of solitary trees, woody vegetation in line, and areal formations across three types of intensively used agricultural landscapes. We recorded 2502 overwintering spiders from 83 species and 20 families, with Linyphiidae being the most abundant. Assemblage composition and abundance were significantly influenced by landscape type, woody vegetation structure, adjacent land use, vegetation identity and litter weight. Linear and areal formations supported more spiders than solitary trees. Grass and leaf litter cover, as well as litter weight, affected both abundance and community composition. No significant differences were found in guild or ballooning traits across landscapes. Spider assemblages also differed between early and late winter, with higher abundance observed at the end of the season.CONCLUSIONOur study highlights that nonproduction elements of woody vegetation are important for the overwintering of spiders in agricultural landscapes. These findings are significant for landscape planning aimed at supporting ecosystem services and biodiversity conservation through the strategic integration of noncrop habitats. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Abstract Agricultural landscape simplification due to the loss of semi‐natural habitats can act as an environmental filter for species and their functional traits. Both local‐ and landscape‐level factors can shape community structure; although through different mechanisms. In this study, we investigated the role of spontaneous grass field margins in enhancing the taxonomic and functional diversity of ground‐active spider assemblages in wheat fields along a landscape diversity gradient. Using pitfall traps, we sampled spiders from 16 wheat fields and three habitat types: the inner field, the field edge and the adjacent grass margin. We collected 2119 spiders (1887 adults) from 72 species and 16 families. Linyphiidae and Lycosidae were the dominant families, comprising 50% and 31% of all sampled individuals, respectively. Landscape diversity had a marginally significant positive effect on functional dispersion, a metric of functional diversity, but did not significantly affect spider activity density or richness. Habitat type had a significant effect on functional diversity but had no effect on activity density and species richness. The spider assemblage in the inner field habitat was less functionally diverse than the assemblages in both the field edge and grass margin habitats. Moreover, grass margins hosted a distinct spider assemblage characterised by larger, free‐hunting and less ballooning species compared to the inner field and field edge habitats. Our results suggest that habitat type, and to a lesser extent also landscape diversity, can support more functionally diverse spider assemblages and contribute to shaping the functional structure of ground‐active spider assemblages. Particularly, spontaneous grass margins can support large, free‐hunting spider species that are absent in wheat fields, potentially enhancing biological control in agricultural landscapes. These results are important for designing agricultural landscapes that promote pest control and for understanding how spider functional traits respond to both local‐ and landscape‐scale factors. Read the free Plain Language Summary for this article on the Journal blog.

ABSTRACTSpiders (Araneae) are generalist predators in agroecosystems and may contribute to biological control in canola (Brassica napus L. and B. rapa L.). However, their diversity and community structure remain understudied in the Canadian Prairies. To address this knowledge gap, we surveyed spider assemblages in the Aspen Parkland region of Alberta, Canada, using pitfall traps placed at field edges and interiors during the 2021 and 2022 growing seasons. We collected 968 spiders in 74 species across 14 families, with Lycosidae and Linyphiidae being the most abundant. Spider abundance was consistently greater at field edges, although family‐level composition varied by year and location. In 2023, we tested pitfall trap modifications to improve spider retention, evaluating (1) trap diameter, (2) preservative substrate (glass beads vs. propylene glycol), and (3) polytetrafluoroethylene (PTFE; Fluon, a non‐stick fluoropolymer) coated trap interiors (to reduce friction and prevent escape). This was tested across canola habitats adjacent to grass‐ or tree‐dominated non‐crop habitat edges. Trap catches, and resulting richness and diversity, were significantly higher in large PTFE‐treated traps, particularly in treed‐edge habitats compared to other treatment combinations. These results underscore the importance of non‐crop field margins in maintaining spider diversity and highlight design improvements to optimize passive sampling. Our findings provide a regional baseline for spider assemblages in canola systems and offer methodological advances to support future ecological monitoring and conservation biological control efforts in Prairie agroecosystems.

Maintaining landscape connectivity for spider assemblages in temperate grasslands: The role of firebreaks in Eucalyptus dunnii plantations

The Białowieża Forest is home to both primary forests under strict protection and commercial forests, which provides an opportunity to compare them in terms of the number of individuals, number of species, and composition of different animal assemblages. The main goal of our study was to compare spider assemblages inhabiting herbaceous vegetation in these two types of forest stands. Spiders were sampled using a sweep net in an oak–lime–hornbeam forest, an ash–alder forest, and an alder carr. More spiders were found in unmanaged stands compared to managed stands, but a significant difference was found only in the alder carr. Total species richness did not significantly vary between managed and unmanaged stands in all forest types. In the oak–lime–hornbeam forest, more species per sample were found in commercial stands compared to primeval stands, while the result was the opposite for the alder carr. Our research did not show a clear negative impact of forest management on plant-dwelling spiders. The impact of forest management was evident in the case of the riparian forest, where the managed stand was characterized by low canopy cover as a result of logging carried out years ago, which is likely to have resulted in differences in family composition.

The aim of this research was to record changes in the population structure of epigeic spider assemblages in the Central European Danube Delta (Slovakia) as a result of habitat management measures and the impact of human intervention. During this research (2020–2023), we assessed the impact of management measures on newly planted forest stands and the effect of grazing in semi-natural conditions, and carried out diversity monitoring in flooded meadows. A total of 6344 individuals belonging to 89 spider species were collected by pitfall traps and identified. Using spatial modelling, we observed the following: (i) there are differences between the structures of managed and unmanaged forest stands (larger number of taxa); (ii) the differences in the number of individuals between study plots and years were statistically significant; (iii) the trend analysis of spider communities showed that study plots that underwent management intervention are expected to see an increase in the number of individuals in the future; and (iv) in the areas that did not undergo management, the number of species was stable. Using spiders as bioindicators could therefore answer the question of whether anthropogenic disturbance disrupts ecological stability. This approach utilizes spiders to assess the sustainability of the landscape.

Biodiversity in agroecosystems is known to be reduced by agricultural intensification and the concomitant decline in landscape heterogeneity. In order to assess the impact of heterogeneity on biodiversity, we conducted a study in which we compared spider assemblages in three pairs of landscapes, each including a highly intensified, fragmented ‘modern’ landscape and a less intensified, heterogeneous ‘traditional’ landscape. Throughout, spiders were sampled in (fragments of) wet meadows by pitfall trapping. We examined the impact of landscape composition and configuration at different spatial scales on the taxonomic diversity and functional composition of spider assemblages in our target patches. Overall, we did not observe differences in species richness or total abundance of spiders between modern and traditional agricultural landscapes. However, functional composition and community structure differed strongly between landscape types, and were also affected by compositional and configurational heterogeneity. In particular, the size and configuration of crop fields was an important factor in shaping spider assemblages. This suggests that modern agricultural landscapes may result in species turnover due to species-specific responses rather than declines in species richness. Therefore, species numbers alone may not be a good indicator of intensification. In order to preserve spider diversity in agricultural landscapes it is necessary to consider the effects of compositional and configurational heterogeneity on taxonomic diversity as well as functional traits and community structure. • Functional diversity of spiders differed between modern and traditional landscapes. • Configurational and compositional landscape heterogeneity affected assemblages. • Agricultural intensification seems to cause species turnover rather than declines. • Conservation measures should consider a reduction in crop field size.

Spiders are important ecological indicators and natural predators that play vital roles in terrestrial ecosystems. This study assessed the abundance, diversity, and distribution of spider species across two ecological zones—rainforest and derived savannah—in Ogun State, southwestern Nigeria. Sampling was conducted using systematic random sampling across various habitats: grassland, fallow bush, agro-ecosystem, and residential areas within Ogun State, Nigeria. A total of 60m × 120m plots were demarcated in each habitat, and spiders were collected using three standard techniques: hand picking, sweep netting, and pitfall trapping. Specimens were preserved in 70% ethanol and identified to family and species levels using established taxonomic keys and reference manuals. Results showed that spider species composition was relatively similar across habitats, but species abundance varied significantly. Families such as Lycosidae, Araneidae, and Salticidae were the most dominant across both zones, while families like Hersiliidae, Amblypygi, and Sparassidae were the least represented. Hogna spp., Pardosa injucunda, Hippasa spp., and Ocyale neatalanta exhibited high abundance, particularly in the rainforest zone. Climatic factors influenced spider activity, with a statistically significant positive correlation between species abundance and temperature (p < 0.01), and a weak, negative, non-significant correlation with rainfall. Seasonal analysis further revealed that spider abundance, particularly of the family Lycosidae, was higher in both wet and dry seasons, with notable declines in other families during the dry season. Despite ecological and climatic differences, the similarity in spider abundance between the two zones was relatively high (80.5%). However, residential habitats showed distinct patterns, with little similarity to other habitat types. The study concludes that habitat complexity, prey availability, and climatic factors are major determinants of spider distribution and abundance. These findings underscore the need for ongoing biodiversity monitoring and the conservation of habitat heterogeneity to sustain arthropod diversity in tropical landscapes.

Although it has its advantages for the development of urban areas, road construction is among the greatest threats to biodiversity, due to fragmentation, habitat loss, and changes in landscape structure. This study investigated the effects of different traffic intensities on the understory spider assemblage in the Brazilian Atlantic Forest. Understory spiders were collected between 09:00 h–16:00 h using beating tray samples on roadside vegetation on roads with and without traffic. In total, 1616 spiders belonging to 24 families and 317 morphospecies were collected. The families Araneidae and Theridiidae were more abundant and showed a higher number of morphospecies on both roads. Understory spiders were classified into seven guilds. However, no significant differences were found in functional and taxonomic richness and abundance between the roads. These results indicate that understory spider assemblages showed no significant response to traffic intensity, suggesting potential resilience to this disturbance in the studied context. Additionally, the proximity between locations may result in the founder effect, with spiders migrating from the preserved site to the impacted site. Overall, this study indicates that traffic presence does not significantly impact the diversity and composition of understory spider assemblages in the studied region.

A Rapid Assessment Protocol (RAP) for non-canopy spiders was used to collect replicate samples from four lowland rainforest sites for a proof-of-concept comparison of spider assemblages from the Democratic Republic of the Congo (hereafter, Congo) and Panama. Collecting was done at two 0.25 ha sites in Panama and two 0.25 ha sites in Congo. At each site, three 0.01 ha plots were randomly located, and within each we did 1 person-hour of aerial sampling (sweeping and beating/brushing) and two person-hours of ground sampling (field sieving of leaf litter). The samples yielded 350 adult spiders belonging to 29 spider families. The Panama samples yielded more adult spiders (235 vs. 115) and more spider families (24 vs. 14) than the Congo samples. Overall, the dominant five spider families in these non-canopy samples were Theridiidae (24%), Salticidae (15%), Linyphiidae (11%), Oonopidae (10%), and Pholcidae (7%), with the 20 remaining families each making up less than 5% of the total adults. The three most abundant families in Congo were Theridiidae, Oonopidae, and Thomisidae, while the top three in Panama were Salticidae, Theridiidae, and Linyphiidae. An NMDS ordination analysis of the four plots failed to show significant differences between any of the four assemblages, but when the plots were analyzed by region, there was a significant difference in the family-level assemblages between the continents. This paper shows proof-of-concept that this RAP can produce statistically valid data from brief sampling trips by teams with inexperienced collectors and simple, inexpensive sampling equipment.