Epigeic Spiders Research Articles

The influence of humidity gradient in a forest on ground spider assemblages: a preliminary study

A forest is a dynamic formation developed through evolutionary transformations that have progressed over a long time. Bioindication can help us understand changes occurring in a forest. Spiders play a significant role in biomonitoring. The presence of stenotopic spiders is affected by several factors, of which water availability is vital. According to the assumptions underlying water retention programs, water accumulated in retention reservoirs is expected to stimulate higher biodiversity of habitats. An analysis of the effect of a moisture gradient on the appearance of epigeic spiders in the Dąbrówka Forest Subdistrict has demonstrated the highest species diversity in the transect located closest to retention reservoirs (93 species). The species diversity of epigeic spiders decreased with the growing distance from these water reservoirs (transect B: 84 species; transect C: 70). Inverse relationships were determined with regard to the numbers of captured spiders (transect A: 927 specimens; B: 1134; C:1288). The spider species that dominated quantitatively was the forest species Pardosa lugubris, caught most abundantly in the area assigned to transect C (76.28%). A higher humidity gradient of a habitat (transects A and B) favors the occurrence of characteristic species with specific habitat and moisture requirements, which are ecologically valuable.

Epigeic spider and ground beetles (Carabid) communities of semi-natural and natural habitats in agricultural landscape in Slovakia

Abstract We studied the spatial structure of spiders and beetles in 4 types of habitats in the Poloniny National Park. Between the years 2020 and 2021, we recorded 1,597 beetle specimens and 3,765 spider specimens using the pitfall trap method. The most represented beetles were Poecilus versicolor (53.4%), Nebria brevicollis (10.3%), Staphylinus caesareus (4.4%) and Amara familiaris (4.1%). Among the spiders, there were species Pardosa pullata (21.81%), Pachygnatha degeeri (14.21%), Xerolycosa nemoralis (10.28%), Pardosa palustris (7.86%), Trochosa ruricola (6.24%) and Alopecosa pulverulenta (4.38%). We confirmed the occurrence of two European important species of beetles (Carabus zawadzkii, Carabus variolosus) and 3 species of spiders belonging to the vulnerable species according to the IUCN threat status (Gongylidiellum vivum, Palliduphantes milleri and Xysticus lineatus). We also found the spider Micaria micans, which is new to the Slovak fauna and information about its distribution and habitat preferences in Slovakia is presented. Using multivariate analyzes (CCA, RDA) and classification species into bioindicative groups, we found a greater connection of adaptable and eurytopic species of ground beetles to the mesophilic meadow and of spiders to the habitat Nardetum pasture. Based on bioindicative groups of species (adaptable, eurytopic and relict), we found only a small difference in percentile points between spiders and beetles.

Salvage Logging and Secondary Succession Promote Spider Diversity in Post-disturbance Stands in Western Germany

Abstract Climate change and biodiversity loss strongly affect ecosystems. In recent years, forests have suffered substantially from climate-induced disturbances resulting in bark beetle outbreaks in coniferous forests. In forest plantations, such disturbances often cause large-scale diebacks, which are frequently salvage-logged. However, the consequences of natural disturbances and subsequent management for forest biodiversity and ecosystem services within plantations are largely unclear. Because they comprise good bioindicators for forest alterations, we here investigated epigeal spider diversity and community composition of three post-disturbance management approaches in former spruce plantations in western Germany. Taxonomic diversity of spiders was significantly enhanced on salvage-logged and secondary succession compared with standing deadwood sites. Nevertheless, the latter provided a refuge for forest specialists, moisture and shade-loving as well as smaller species, whereas the other two management categories were mostly inhabited by larger spiders associated with open habitats. Because all three post-disturbance management approaches harbored highly distinct spider communities and divergent functional guilds, we propose the application of a variety of management approaches for bark beetle-affected spruce plantations. The resulting habitat heterogeneity will likely enhance the biodiversity of spiders and other taxonomic groups. Study Implications: Bark beetle outbreaks became severe disturbances in spruce plantations. The management of affected stands usually aims at mitigating economic losses, but within the current biodiversity crisis, it is increasingly important to consider ecological consequences. This study shows that salvage logging or secondary succession can increase spider taxonomic diversity, although forest species preferred standing deadwood sites. All management categories harbored highly distinct spider assemblages characterized by different ecological and functional guilds. Our results indicated that spider communities were influenced by canopy openness, microclimate, and competition rather than post-disturbance management. Therefore, management practices should include diverse approaches to foster many different spider assemblages.

Effects of mowing on body size patterns in spider assemblages of mesic meadows.

Habitat disturbance affects not only the abundance, species richness and species composition of the local fauna, but also the body size of specific individuals and body size patterns in animal assemblages. Particularly large disturbances occur in agroecosystems, where many agricultural treatments are carried out. One of them, which is most commonly applied to grasslands and which significantly damages the habitat structure, is mowing. We examined the effect of mowing on mean, skewness and kurtosis of the body size in epigeic spider assemblages. The research was conducted on mesic meadows in eastern Poland, in an agricultural landscape typical for this region, consisting of a mosaic of meadows, fields and forests. Spiders were collected using pitfall traps in two sampling periods: the first before mowing and the second when part of the meadows had been mown. Mowing had no significant effect on mean body size, skewness and kurtosis of the body size in epigeic spider assemblages. However, after the cut, mown plots showed, on average, significantly smaller spider species than unmown plots. Both the value of skewness and kurtosis significantly increased after mowing but to the same extent on both the control and mown plots. The decrease in mean body size and increase in skewness in spider assemblages were mainly due to an increase in the number of small species from the Linyphiidae family. It is likely that these species began to migrate (via ballooning) during the second sampling session, following the start of haying, and were thus caught in traps more frequently. Our study showed no clear, significant changes in the body size structure of epigeic spiders in mown meadows compared to unmown ones, which may suggest that the mowing, where extensive farming is practised, does not have a long-term significant negative impact on this group of invertebrates.

Intense game grazing shapes epigeic spider communities of pedunculate oak Quercus robur plantations in anthropogenic environments

Game browsing affects nature conservation because the interests of hunters and gamekeepers often lead to high game stocking rates. However, the compositional effects of game browsing on invertebrates are insufficiently understood. We addressed the dynamics of epigeic spider communities in oak stands planted in newly formed anthropogenic environments under the facultative pressure of browsing game. The study site consisted of an open-cast lignite mine and an overburden deposit in NW Czechia. Using pitfall traps, we examined five habitat types (four transects per habitat type): Quercus robur stands ≥ 25 years of age, 12–24 years of age, and 0–2 years of age; Q. robur stands 12–24 years of age that were heavily damaged by game browsing; and sites subject to spontaneous succession for 12–22 years. We captured 9459 individuals from 134 spider species distributed unevenly across the examined habitat types. The young stands were dominated by Pardosa agrestis, Pardosa monticola, and Oedothorax apicatus, whereas Pardosa prativaga, Pardosa lugubris, Pisaura mirabilis, and Alopecosa cuneata dominated the old stands. The stands damaged by browsing had the highest species richness and were dominated by Alopecosa pulverulenta, Xerolycosa miniata, A. cuneata, and Trochosa ruricola. All the oak stands were rich in threatened species, with most (26) found in habitats damaged by browsing, whereas the youngest stands hosted the lowest number of threatened species (11). The species dominating old stands still included species that prefer greater canopy openness, such as P. lugubris, whereas numerous species of central European climax oak forests were lacking. In conclusion, we identified oak stands heavily damaged by game browsing as a unique environment that shapes the community of epigeic spiders and that differs from epigeic spider communities of oak stands of various ages and those colonizing areas that are allowed to undergo spontaneous succession.

On epigeic spider assemblages (Arachnida: Aranei) of oak forests in the Leopard Land National Park and the Kedrovaya Pad’ Reserve, Maritime Territory, the Russian Far East

On epigeic spider assemblages (Arachnida: Aranei) of oak forests in the Leopard Land National Park and the Kedrovaya Pad’ Reserve, Maritime Territory, the Russian Far East

Non-native Douglas fir promotes epigeal spider density, but has a mixed effect on functional diversity

With climate change altering ecosystems worldwide, forest management in Europe is increasingly relying on more adaptable non-native tree species, such as Douglas fir (Pseudotsuga menziesii). However, the ecological consequences of the increased utilization of Douglas fir on arthropod diversity and ecosystem functioning are not fully known. Here we assessed how non-native Douglas fir as well as large- and small-scale differences in the environmental context, affect epigeal spider abundance, biomass, taxonomic and functional diversity, and community structure in Central European forests. Our study sites were divided into two regions with large differences in environmental conditions, with seven replicates of five stand types, including monocultures of native European beech (Fagus sylvatica), non-native Douglas fir and native Norway spruce (Picea abies), as well as two-species mixtures of European beech and each of the conifers. Contrary to our expectations, Douglas fir promoted small-scale spider diversity, and abundance and biomass (activity density). On the other hand, it decreased spider functional divergence and altered spider community structure. Microhabitat characteristics had opposing effects on spider diversity and activity density, with more open stands harboring a more diverse but less abundant spider community. Overall, our findings suggest that increasing Douglas fir utilization at the expense of Norway spruce does not necessarily decrease the diversity of epigeal arthropods and may even promote local spider diversity and activity density. However, care needs to be taken in terms of biodiversity conservation because typical forest spider species and their functional divergence were more strongly associated with native beech than with coniferous stands.

Contact exposure to neonicotinoid insecticides temporarily suppresses the locomotor activity of Pardosa lugubris agrobiont wolf spiders

Exposure to numerous chemicals disrupts the spiders' locomotion. Spiders, particularly epigeic spiders, are dependent on their locomotory activities to search for prey, hide from their enemies, and perform sexual reproduction and subsequent parental care. Among the best-known compounds that inhibit the locomotion of arthropods are neonicotinoids. Despite spiders are less affected by the neonicotinoids than insects due to the sequence differences in their acetylcholine receptors, they are not resistant to these compounds. We hypothesized that acute exposure to a broad spectrum of neonicotinoids suppresses the traveled distance, mean velocity, and maximum velocity in epigeic spiders. As a model species, we used adults of Pardosa lugubris. We tested commercial formulations of thiamethoxam, acetamiprid, and thiacloprid. We tested each of the neonicotinoids in the maximum and minimum concentrations recommended for foliar applications. We applied them under controlled conditions dorsally by spraying them directly on the spiders or exposing the spiders to the tarsal contact with neonicotinoid residues. Control groups consisted of 31 individuals; treated groups consisted of 10–21 individuals. We found that a broad spectrum of neonicotinoids temporarily suppresses the traveled distance in epigeic spiders. At 1 h after application, all the three tested neonicotinoid insecticides induced declines in the traveled distance, but this effect mostly disappeared when tested at 24 h after the application. The decrease in the traveled distance was associated with substantial temporary decreases in the mean and maximum velocities. Despite differences among modalities, all three insecticides caused multiple adverse effects on the locomotory parameters in any tested concentrations. It remains to test what would be the lowest safe concentration for the chronic exposure to neonicotinoids in epigeic spiders.

Effect of plant composition on epigeal spider communities in northern New Zealand forest remnants

Te Paki Ecological District (TPED) in northern Northland, New Zealand, is well known as an ecologically significant centre of endemism. However, due to extensive anthropogenic habitat degradation, native forest has been reduced to small, isolated remnants and many of its endemic species are threatened with extinction. Epigeal spider communities (species living on or near the ground) were surveyed within TPED by pitfall trapping at seven native forest remnants differing in plant composition and apparent seral stage to investigate how spider communities varied within them.

Functional diversity of epigeal spiders in the olive grove agroecosystem in northeastern Portugal: a comparison between crop and surrounding semi‐natural habitats

AbstractThe olive grove agroecosystem (Olea europaea L., Oleaceae) is very important in terms of economy and culture throughout the Mediterranean region. In Trás‐os‐Montes (Portugal), olive groves are commonly surrounded by semi‐natural areas consisting of Mediterranean shrublands. Understanding the role of potential predators of olive pests is crucial to enhancing biological control in sustainable agriculture. This study aimed to investigate the community structure of ground‐inhabiting spiders (Arachnida: Araneae) in the olive grove and their surrounding shrublands in Trás‐os‐Montes. We found that the community of spiders was dominated by ground hunters such as Lycosidae and Gnaphosidae. Lycosidae were more abundant in olive groves than in surrounding shrublands in 2015 only, whereas Gnaphosidae were more abundant in olive groves in both years of the study (2015 and 2016). Hence, the two habitats displayed a low complementarity of spider families. The Mediterranean shrubland areas could act as a reservoir and refuge for potential pest biocontrol agents. Conservation of surrounding semi‐natural areas may contribute to the natural limitation of pests exerted by spiders in the olive grove agroecosystem. Nevertheless, further long‐time and species‐level studies are needed to provide insights into the role of spiders as natural enemies.

Recovered grassland area rather than plantation forest could contribute more to protect epigeic spider diversity in northern China

Several studies have documented the semi-natural habitats and heterogeneous landscape patterns play a crucial role in maintaining spider diversity in agricultural landscapes. However, which types of semi-natural habitat contribute more to conserve spider diversity and functional traits, and how they respond to landscape patterns at different landscape scales are still poorly understood. Thereby, we sampled epigeic spider communities by pitfall traps within recovered grasslands, plantation forests and croplands around three villages with different altitudes in northern China and surveyed the surrounding landscape structures in both 2017 and 2018. The results confirmed the diverse distribution of spiders in different habitat types. There was a greater spider activity density in recovered grasslands than that of plantation forests or croplands significantly. Furthermore, both recovered grasslands and plantation forests contained more species richness than croplands. Moreover, the spider community in the recovered grasslands and cropland had more similar functional trait compositions (including hunting types, body size and ballooning ability) comparing to the plantation forests, which mainly due to the higher proportion of ambush hunters in recovered grassland and cropland. Secondly, the study also indicated that the proportion area of plantation forest negatively affected spider diversity at multi-scales. Meanwhile, recovered grassland with high landscape diversity would benefit spider diversity only on a small scale like a 100 m radius. The spider functional traits were insensitive to landscape patterns. Overall, the study implies that increasing recovered grassland rather than plantation forest could protect spider diversity in northern China. The findings presented in this paper added to our understanding of how landscapes and different semi-natural affect the diversity of spiders and their functional traits. Meanwhile, the research results represent a further step towards developing more suitable landscape patterns and choosing restoration semi-natural types for policymakers to enhance biodiversity in agricultural landscapes.

Resilience of epigeal spiders (Araneae) after clear-felling for agriculture in a Central African rainforest

Epigeal spiders were collected in five lowland rainforest habitats of the Masako Reserve (Kisangani, RD Congo): primary forest (>200 y. old), old secondary forest (± 80 y.), young secondary forest (40 y.), old fallow (12 y.) and young fallow (5 y.). The density and spatial distribution of spider populations were estimated by means of nocturnal distance sampling performed in all habitats except young secondary forest, and by pitfall trapping, applied in all five habitats. The epigeal spiders of the Masako forest belong to 62 species in 25 families. The most frequent families are Ctenidae, Lycosidae, and Sparassidae in the distance samples, and Zodariidae, Salticidae, and Corinnidae in the pitfalls. The density of the Ctenidae increases in an ascending sequence from 0.007 ind. m-2 in young fallow to 0.103 ind. m-2 in primary forest. For Lycosidae the sequence is inversed. They are by far the most common in young fallow (0.028 ind. m-2) and virtually absent in primary forest. Typical forest spiders, absent from open habitats, are common in old fallow which means that after 12 years, the typical forest fauna is already re-established. Only the young fallow fauna is clearly different from that of the other habitats, which confirms the high resilience and recolonization potential of epigeal spiders.

Effect of geography and altitude on the community characteristics of epigeic spiders in rice field levees

Effect of geography and altitude on the community characteristics of epigeic spiders in rice field levees

Epigeic spiders from oak-hornbeam woodland in the Děvín National Nature Reserve (Czech Republic)

Data on the spider fauna from the forest ecosystems of the Děvín National Nature Reserve (South Moravia, Czech Republic) are presented. The research was carried out on 15 randomly chosen research plots in oak-hornbeam forest stands within different management regimes. Spider sampling was done by pitfall trapping from May to October 2016. Overall, 3683 adult spiders belonging to 22 families, 70 genera and 116 species were collected. The families Linyphiidae, Lycosidae, Gnaphosidae and Thomisidae exhibited high species richness. The most abundant species were Pardosa lugubris (Walckenaer, 1802) and Trochosa terricola Thorell, 1856. Faunistically remarkable species were Atypus piceus (Sulzer, 1776), Drassyllus villicus (Thorell, 1875), Gnaphosa montana (L. Koch, 1866), Panamomops affinis Miller & Kratochvíl, 1939 and Walckenaeria monoceros (Wider, 1834). The record of Gnaphosa montana is one of the first accounts of this psychrophilic spider from European lowlands. Of the identified species, 23 are listed in the Red List of Threatened Species in the Czech Republic (EN – 1 species, VU – 12 species, LC – 10 species).

Habitat heterogeneity supports epigeic arthropods after prescribed burning of dry grasslands

Fire supports landscape openness; thus, prescribed burning could be an effective management in open landscapes. In this study we tested the response of arthropods (spider, ground beetle, rove beetle and woodlouse) to dormant-season prescribed burning in dry grassland patches. We hypothesized that the unburned patches support the arthropods recolonizing the burned patches; thus, fire causes no serious damage to the arthropod assemblages. Epigeic arthropods (spider, ground beetle, rove beetle and woodlouse) were collected by unbaited pitfall traps containing ethylene glycol as a killing-preserving solution. Altogether 60 traps worked in 3 burnt and 3 control plots (10 traps/plot). Traps were emptied monthly from May to October in the year after burning. Collected arthropods were identified at species level using standard keys. We found no significant difference between the burned and control plots for the abundance, species richness, and Shannon diversity of spiders, ground beetles, rove beetles and woodlice. Differences in total abundance, species richness and diversity of arthropods were also not significant between the burned and control plots. Among from 12 most abundant species, ten species was not affected by burning, while the abundance of Titanoteca veteranica spider species increased and the abundance of Trochosa robusta spider species decreased in the burnt plots. Microcaves and other unburned microhabitats in and around the burned patches serve as refuge for epigeic arthropods supporting the fast recolonization after prescribed burning, although the abundance of some epigeic spider species (Titanoteca veteranica, Trochosa robusta) was affected by burning. Our findigs revealed that prescribed burning is a potentially promising conservation method. We also highlighted that preservation of unburned microhabitats and surroundings of the managed patches is essential during the prescribed burning.

Liming alters body size distribution in a community of epigeic spiders in birch forest (Betula pendula Roth)

Liming, an ameliorative method for acidified forest soils, affected the relative abundance of prey of ground-hunting spiders and consequently reduced densities of functionally similar species of these predators. Liming, an ameliorative method for acidified forest soils, may modify the structure of an arthropod community by altering the soil characteristics and/or the availability of food resources. We investigated the effect of liming on the community structure of ground-hunting spiders in a birch forest. We established six experimental birch stand plots. Each stand was exposed to one of three experimental treatments: control, 1.5 t/ha, or 3 t/ha of dolomitic limestone. We collected spiders using pitfall traps during 5 years. We characterized the community in terms of activity density, species richness, community-weighted mean body size, and functional diversity and evenness in body size. We further investigated the potential links through which the liming might affect spiders, namely soil characteristics, effect of liming on birch, and densities of potential prey. The commonly used dosage of 3 t/ha reduced densities of functionally similar species which led to the reduced functional evenness in body size and increased functional divergence in body size. Liming increased soil pH only slightly but decreased the densities of spiders’ preferred prey. The liming affected the community of ground-hunting spiders, at least partially, through reduced densities of their preferred prey.

Ground-dwelling spider assemblages in contrasting habitats in the central South African Grassland Biome

Background: Ground-dwelling spider assemblages in shrublands and cultivated pastures in the South African Grassland Biome have never been comprehensively studied.Objectives: Epigeic spiders were collected in eight different habitats in the Amanzi Private Game Reserve in the Free State to determine assemblages of different vegetation types.Methods: Three of the sampled habitats were contrasting low-lying shrublands; three were contrasting hill aspects (northern slope, southern slope and plateau) in the Buddleja saligna–Searsia burchellii–Olea europaea africana subcommunity; one habitat was cultivated Digitaria eriantha pastures, and the last habitat was an area in and around a freshwater dam. Spiders were sampled by pitfall trapping in early spring (Sept. 2012), mid-summer (Jan. 2013), mid-autumn (Apr. 2013) and mid-winter (July 2013).Results: A total of 2982 adult spiders were collected, representing 129 species and 33 families. Ammoxenidae was the most abundant family (40.85%), followed by Gnaphosidae (21.26%), Zodariidae (10.80%) and Salticidae (10.26%). Gnaphosidae was the most species-rich family (24.81%), followed by Salticidae (13.18%), Lycosidae (11.63%) and Zodariidae (6.20%). Spider activity densities and species richness did not differ significantly between habitats, although significant seasonal fluctuations were detected. The three hill aspects and cultivated D. eriantha pastures had the most distinct assemblages, while those of the three low-lying shrublands and freshwater dam showed considerable overlap.Conclusions: Our results indicate that the aspect of hills has a significant effect in shaping spider assemblages, while the vegetation composition of shrublands is not strongly influential. The unique spider assemblages of cultivated D. eriantha pastures can be attributed to the absence of woody plants.Conservation implications: This was the first study to investigate ground-dwelling spider assemblages in shrublands and cultivated pastures in the South African Grassland Biome. Our study confirms that hill aspects, shrublands and pastures harbour very different spider faunas. When identifying land for potential expansion or establishment of protected areas, conservation planners should ensure that the greatest diversity of vegetation units are included to optimise the conservation of biodiversity.

First evidence of the formation of secondary strongholds of threatened epigeic spiders (Araneae) in oligotrophic anthropogenic wetlands that form in sand pits and gravel-sand pits

The absence of evidence regarding the ecosystem services of habitats affected by sand mining has had direct effects on the destiny of landscapes affected by human disturbances. Active sand pits and gravel-sand pits cover 0.1% of the study area, the Czech Republic. In many sand pits, various types of oligotrophic wetlands may form; these range from periodic pools to peat bogs and purposefully formed water bodies. In the present study, we aimed to provide the first conclusive evidence of ability of sand pit wetlands to serve as secondary strongholds for both common and threatened wetland-associated epigeic spiders. We examined 21 anthropogenic wetlands in Czech sand pits and gravel-sand pits using pitfall trapping (17,764 trap-days) for the presence of spiders, and characterized various abiotic variables and the cover and composition of plants in the analyzed microhabitats. We found 5,842 individuals from 224 spider species, including 52 Red-Listed species and one previously undescribed Scutpelecopsis sp. All types of examined anthropogenic wetlands were associated with low dominance and high entropy, with the least stable assemblages present in gravel-sand pit tailing ponds. The examined anthropogenic wetlands hosted 60% of the species that were previously found in (near-)natural wetlands within the study region, and hosted numerous species that were absent from (near-)natural wetlands. During the sampling period, four study sites were affected by severe June floods, which caused prominent changes in species-specific spider abundances but caused a disappearance of only a few species, including Pardosa prativaga and Xerolycosa miniata. Oligotrophic anthropogenic wetlands occurring in sand pits and gravel-sand pits serve as local biodiversity hotspots, and their value should be taken into consideration when planning restoration and rehabilitation of areas affected by sand and gravel-sand mining.

Epigeal spider assemblage responses to vegetation structure under contrasting grazing management in upland calcareous grasslands

Abstract Calcareous grassland is one of the most species rich and diverse habitats within Europe, but has faced decline due to agricultural intensification and abandonment. In recent years, conservation organisations have altered grazing practices in an attempt to maintain floristic components. However, there has been little consideration of the effects of changes in grazing practices on invertebrates. This study determines the impacts of commonly used grazing practices in upland calcareous grasslands on spiders in relation to vegetation structural complexity. Typical grazing management regimes were examined in three regions of upland calcareous grassland in Britain. Spiders were sampled from April to August 2014 and vegetation structural complexity was recorded in 2 × 2 m quadrats paired with pitfall traps sequentially throughout the sample period. There were three distinct spider assemblages among the grazing regimes; ungrazed, heavy sheep grazed and one shared between cattle and light sheep (which had a comparable grazing intensity). The distinct spider assemblages among grazing regimes can be attributed to the interaction of grazing and habitat structure. Increased vegetation structural complexity in ungrazed regimes resulted in an assemblage dominated by ‘sheet web weavers’ (dominated by Linyphiidae). In contrast, reduced vegetation structural complexity and homogeneity in heavy sheep grazing resulted in an assemblage dominated by ‘other hunters’ (including Oedothorax and Erigone genera). Grazing regime alters vegetation structural complexity and is important in supporting distinct spider assemblages. This research indicates that low intensity conservation grazing regimes, in addition to no grazing, should be promoted across upland calcareous grassland landscapes to maintain heterogeneity.

Effects of uncut hay meadow strips on spiders

Standard management of Czech hay meadows consists of machine mowing twice a year, with the first mowing in or before mid-June and the second mowing 40–60 days later. Here, we aimed to analyse the effects of the first year of implementation of the agri-environment scheme (AES), which consisted of allowing 3–10% of permanent grasslands within each land block to remain unmown until at least August 15, on the abundance and diversity of spiders. We conducted the study at 40 paired sampling sites in three meadow types in northern Czechia. Spiders were sampled using pitfall traps and sweeping, and the plant cover and vascular plant species composition were analysed. Nearly all study sites were associated with 100% vegetation cover, and hosted 209 vascular plant species, of which 12 were threatened. The number of vascular plant species exhibited only modest differences between the study sites under standard and AES-prescribed management. We captured a total of 3889 individuals of 103 spider species. The abundance of spiders was three-times higher at sites subjected to AES management. The number of species was similar irrespective of the management applied, but the species composition differed in response to the management (Sorensen index 0.562–0.736). The AES management was associated with higher abundance of common vegetation-dwelling farmland spiders, but epigeic spiders decreased there or were insensitive to AES management. It remains to be investigated whether threatened vegetation-dwelling spiders may benefit from similar AESs at sites of their occurrence, such as in fen meadows or steppes.