Spider Assemblages Research Articles

A multidiversity approach to investigate the impact of mining exploitation on spider diversity in the abandoned mine district of Montevecchio-Ingurtosu (Sardinia, Italy).

The impact of mining activities on spider (Araneae) diversity and assemblages was studied in two abandoned mine sites in Sardinia (Italy), where mining activities started in the middle of the nineteenth century and closed down over a century later. Spider community composition was analysed in dumps, undisturbed forests and scrublands which represent the natural chronosequence following the abandonment of the mining district. The identification of spiders was performed at the lowest taxonomic level possible and differences in abundance, species richness (SR), and functional diversity (FD) were analysed. Nonmetric multidimensional scaling (NMDS) and a permutated multivariate analysis of variance (PERMANOVA) routine were conducted to evaluate the relationships of spider assemblages with land cover, and the indicator species analysis was performed to identify the typifying species. During the entire sampling period, 2312 spiders were captured, and approximately 80% of the total were identified at the species level (79 spider species belonging to 28 different families). No differences in abundance and SR were found, whereas FD, which showed the highest values in forests, significantly differed among sites. A distinct separation among assemblages and a significant effect of the land use on spider assemblages were found (PERMANOVA, R2 = 0.59, p < 0.001). Twelve species were selected as indicator species. Our results underlined the possibility to consider ground-dwelling spiders as a valuable target group for biomonitoring programmes supporting projects of near-natural restoration and/or technical reclamation of mining sites.

Efficacy of trapping techniques (pitfall, ramp and arboreal traps) for capturing spiders

Pitfall traps are the most commonly used method for capturing spiders. Other inexpensive methods such as ramp traps and arboreal traps are also used. Ramp traps are used mostly in situations where you cannot or do not wish to disturb the soil, while arboreal traps are used to determine the structure of spider assemblages living on tree trunks and in the canopy. Spiders were sampled from 17 localities on Kozuf Mt. and the effectiveness of four different trapping methods was compared. Overall, the largest amount of species and individuals was captured in pitfall traps. However, some of the species were only captured with ramp and arboreal traps. This, along with the previously mentioned characteristics of ramp and arboreal traps confirms the usefulness of these trapping methods for a more accurate assessment of spider biodiversity.

Farming system shapes traits and composition of spider assemblages in Mediterranean cherry orchards.

Habitat properties, including crop type, farming system, management practices, or topographic features such as the hillside aspect, may act as environmental filters that select organisms sharing traits compatible with those conditions. The more environmentally-friendly management practices implemented in organic farming seem to benefit a range of taxa, but the extent of those benefits is not well understood. In cherry orchards of the Jerte Valley (Extremadura, western Spain), we explored the response of spider assemblages to the farming system (organic and conventional) and the hillside aspect (sunny or shady) from a taxonomical, behavioral, and morphological perspective. Spiders from both the canopy and soil surface were collected and identified to family. According to their foraging strategy, spiders were sorted in guilds and, for a selected family in each guild, body size was measured on each captured individual. Spider traits and composition were determined by local factors derived from farming system, and by climate conditions associated to the hillside aspect. In taxonomical terms, spiders benefit from organic farming and by the shady aspect. However, from a behavioral perspective, spiders with different foraging strategies exhibit strong variations in their response to the evaluated factors. From a morphological perspective, body size within guilds is differently conditioned by management practices that constitute conditioning disturbance events for each guild, resulting in selecting small individuals. The observed differences in taxonomical, behavioral, and morphological responses of spider communities to habitat properties highlight the importance of examining their assemblages from different perspectives when assessing how they respond to changes in management practices and topographic features.

Non-native spiders change assemblages of Hawaiian forest fragment kipuka over space and time

We assessed how assemblages of spiders were structured in small Hawaiian tropical forest fragments (Hawaiian, kipuka) within a matrix of previous lava flows, over both space (sampling kipuka of different sizes) and time (comparison with a similar study from 1998). Standardized hand-collection by night was carried out in May 2016. In total, 702 spiders were collected, representing 6 families and 25 (morpho-)species. We found that the number of individuals, but not species richness, was highly correlated with the area of sampled forest fragments, suggesting that kipuka act as separate habitat islands for these predatory arthropods. Species richness was significantly lower in the lava matrix outside the kipuka compared to the kipuka habitats, although there was no statistical difference in species composition between the two habitats, largely because of similarity of non-native species in both habitats. Over the last 20 years, the abundance of non-native spider species substantially increased in both kipuka and lava habitats, in marked contrast to the vegetation that has remained more intact. With endemicity of terrestrial arthropods reaching over 95% in native forests, non-native predatory species present a critical challenge to the endemic fauna.

The spider diversity and plant hopper control potential in the long-term organic paddy fields in sub-tropical area, China

Previous studies showed that organic farming augmented natural enemies and enhanced pest control in the agroecosystem, but the effect may change over time, as long-term application of different cultivation methods would gradually affect the agricultural systems. In this paper, spider diversity and its plant hopper control potential were assessed in paddy fields cultivated organically for 5 (OR5), 10 (OR10) and 15 (OR15) years and in conventional paddy fields (CR). The results showed that the abundance, richness and Pilou evenness of spiders in organic paddy fields were significantly higher than those in conventional paddy fields were, but no significant difference found between OR5, OR10 and OR15. There was no significant difference between Shannon Wiener index (H') of spiders in organic and conventional paddy fields. There was no distinct difference in spider assemblage composition between conventional and organic paddy fields, and a considerable overlap between the organic paddy fields with different organic farming period. Plant hopper was less abundant in organic paddy fields than conventional ones in rice blooming stage, but there was no difference in other rice growth stages. A higher number of the spider species in organic paddy fields had large temporal overlap with plant hopper than that in conventional fields. Adopting organic practices in paddy fields can maintain a high diversity of spiders across rice paddy ecosystems, although there was not significant increase of spider diversity over time after five years since transition.

Spiders (Arachnida: Araneae) in organic apple (Rosaceae) orchards in southeastern France

Abstract The role of spiders (Arachnida: Araneae) in biological control programmes has received less attention than that of insect natural enemies. The aim of this two-year study was to obtain descriptive data on spider spring field population structure and dynamics. The study was carried out in one insecticide-free and four organic apple orchards in southeastern France. Rolls and bands of corrugated cardboard near the ground and shoots infested with Dysaphis plantaginea (Passerini) (Hemiptera: Aphididae) in the tree canopy were used to sample spiders. Thirty-three spider species belonging to 14 families were identified from both sampling methods. Cheiracanthium mildei Koch (Araneae: Cheiracanthiidae) was clearly the predominant arboreal spider species in aphid-infested shoots (&gt;57%). More than half of the spiders recorded in cardboard bands belonged to three species Drassodes pubescens (Thorell) (Araneae: Gnaphosidae), Pseudeuophrys erratica (Walckenaer) (Araneae: Salticidae), and Icius hamatus (Koch) (Araneae: Salticidae). Salticidae (39.9%) and Gnaphosidae (23.4%) families dominated significantly the spider assemblages observed in the cardboard rolls and were present on almost all sampling dates. However, in the two shelter types, the spider abundance curve clearly had a poly-modal shape. This may be due to the sequential arrival of some spider species or their dominance in a certain period of our study.

Spider assemblages in grass tussocks in central South Africa (Arachnida: Araneae)

A comparative survey was done of the spider assemblages found in grass tussocks of three grass species (Cymbopogon pospischilii, Eragrostis lehmanniana and Themeda triandra) occurring in three different habitats (hillside, open grassland and around a freshwater dam) in a central Free State grassland. We aimed to determine whether spiders displayed preferences for particular grass species and habitats with varying characteristics. Spiders were caught from the base of grass tussocks by hand using vials. A total of 491 spiders representing 24 families and 56 species were sampled from 270 tussocks, with Philodromidae (16.8%), Gnaphosidae (15.0%), Lycosidae (11.3%) and Trachelidae (10.9%) the dominant families. We found that neither grass species nor habitats significantly affected the abundance, species richness or assemblage structure of spiders, but that sampling month did affect abundance and richness, particularly when considering its interaction with habitat and grass species. Two of the four dominant species showed distinct preferences for particular grass species, Tibellus minor for the thicker-stemmed Cymbopogon and Themeda, and Obatala sp. for the more sparse tussocks of Eragrostis. We suggest that tussock-dwelling spiders are, for the most part, habitat generalists, occupying any available grass species. However, further study is necessary to determine the role of grass structure on particular spider species.

Relative Efficiency of Pitfall Trapping vs. Nocturnal Hand Collecting in Assessing Soil-Dwelling Spider Diversity along A Structural Gradient of Neotropical Habitats

Assessing spider diversity remains a great challenge, especially in tropical habitats where dozens of species can locally co-occur. Pitfall trapping is one of the most widely used techniques to collect spiders, but it suffers from several biases, and its accuracy likely varies with habitat complexity. In this study, we compared the efficiency of passive pitfall trapping versus active nocturnal hand collecting (NHC) to capture low understory-dwelling spider taxonomical (morpho-species) and functional (hunting guilds) diversity along a structural gradient of habitats in French Guiana. We focused on four habitats describing a structural gradient: garden to the orchard to the forest edge to the undisturbed forest. Overall, estimated morpho-species richness and composition did not vary consistently between habitats, but abundances of ground-hunting spiders decreased significantly with increasing habitat complexity. We found habitat-dependence differences in taxonomic diversity between sampling strategies: NHC revealed higher diversity in the orchard, whereas pitfalls resulted in higher diversity in the forest. Species turnover resulted in high dissimilarity in species composition between habitats using either method. This study shows how pitfall trapping is influenced by habitat structure, rendering this sampling method incomplete for complex, tropical environments. However, pitfall traps remain a valuable component of inventories because they sample distinct assemblage of spiders.

Islands in cities: Urbanization and fragmentation drive taxonomic and functional variation in ground arthropods

The conversion of natural lands in urban areas is exponentially increasing worldwide, causing a major decline in biodiversity. Environmental alterations caused by urbanization, such as land conversion and isolation of natural patches, favour tolerant and generalist species, causing both species loss and replacement. In addition, selective pressure is exerted on particular functional traits, driving a functional homogenization or turnover of biotic communities. We sampled ground arthropods within the municipality of Turin (NW-Italy), wherein an isolated and a connected control subplot were repeatedly sampled at 15 stations distributed along a gradient of increasing urbanization. Such a nested sampling design allowed us to investigate the taxonomic and the functional responses of carabids and spiders to both the urbanization level and patch isolation. First, we highlighted the dominant role played by species homogenization (nestedness) in explaining both taxonomic and functional variation in both groups of arthropods. Secondly, we showed that urbanization causes simultaneously functional homogenization and replacement in both carabid and spider assemblages, whereas patch isolation influences carabid species composition and homogenizes and shifts spider taxonomic and functional composition. Lastly, by relating community-weighted means of body length, dispersal capacity and trophic strategy to the urbanization and isolation gradients, we demonstrated that urbanization alters the trophic structure of both taxonomic groups and increases the average dispersal capacity of spiders. On the other hand, patch isolation affected the functional composition of spiders only, reducing the body size and increasing dispersal capacity and the proportion of web-builder species. Our results demonstrate that both urbanization and patch isolation alter species composition by causing functional and taxonomic homogenization. In addition, they exert a strong filtering effect on community functional traits, increasing the proportion of phytophagous species in carabids, and increasing dispersal capacity and web-builders occurrence in spiders, while reducing spider body size.

Passive Re-colonization of the Spider Assemblage on an Ohio Restored Tall Grass Prairie Compared to Nearby Remnant Prairies and Old Fields

The reconstructed prairie on the Marion Campus of The Ohio State University was established in 1977. Since then restoration has focused on plants. Animals on the site have recolonized without active management. Spider assemblages were sampled in 2000 and compared to those sampled at the time on 2 remnant prairies and 2 old fields. Pitfall traps and sweep nets were used for sampling. In 2000, spiders (n = 1,541) representing 94 species were captured; 91% of these were captured with pitfall traps. The restored Marion Campus Prairie was inhabited by an assemblage of spiders resembling those on nearby remnant prairies and old fields.

Field survey of foliage-dwelling spiders (Arachnida, Araneae) in Peninsular Malaysia

Diversity of spider groups have received less research attention and there are limited published references for spiders from Peninsular Malaysia. The current survey was conducted to locate and identify foliage-dwelling spiders (Arachnida, Araneae) at five different sites in Peninsular Malaysia. Spider specimens were collected using manual search and sweep-netting between September 2012 and November 2012. A total of 92 morpho-species from 65 genera that belong to 15 families have been successfully recorded and identified. The greatest proportion of specimens captured (40%) were Foliage-runners (Clubionidae, Miturgidae, Oxyopidae, Pisauridae, Salticidae, Scytodidae, Thomisidae), followed by orb-weavers (Araniedae, Nephilidae, Tetragnathidae, Uloboridae) (36.5%), space-weavers (Pholcidae, Psechridae Theridiidae) (21.5%) and ground-dwellers (Sparassidae) (2.0%). Cluster analysis has revealed that the same habitat types share a more similar diversity composition compared to different habitat types, which indicates that spider assemblage composition was partly co-dependent on vegetation structure. However, no significant difference in spider assemblage composition was found between all the five sites which follows that these diurnal group of spiders are actually adaptable to various habitat types.

Taxonomic and functional differentiation of spiders in habitats in a traditional olive producing landscape in Italy

Annual crops are generally assumed to host simplified arthropod communities that depend on immigration from the surrounding landscape. Perennial, low-input crops such as olive groves are likely to depend less on immigration from other habitats, however, studies on the landscape ecology of perennial crops are scarce. This paper studies the assemblages of arboreal spiders in three types of habitats adjoining olive groves: woods, garigue and other cultivated olive groves in a traditional olive producing landscape. Spiders were sampled during summer and the three types of habitats were compared in terms of species, families and functional groups in order to determine differences in diversity and the potential for spider spillover. As is often reported for annual crops, olive groves had a lower alpha and beta diversity than more natural habitats in terms of species, with a strong dominance of a single species, Frontinellina frutetorum (C.L. Koch, 1834). Differences in diversity between olive groves and natural habitats were not significant at family or functional group levels. With the possible exception of orb weavers, this study indicates that the spiders that were common in olive groves did not occur at higher densities in habitats that were more natural. This indicates there is limited spillover between perennial crops and other late-successional habitats. The enhancement of spiders in olive orchards for pest control may thus depend more on local management than on the presence of semi-natural habitats as a source of immigration.

New data on the spider fauna (Araneae) of the Penza Region (Russia)

Arachnological research in the Penza Region was conducted in the 1980s and in the mid-2000s only. Initially, a list of 112 species was published and spider distribution within five types of habitats throughout the region was analyzed (Pyatin, 1988). Later on, spiders were studied in four segments of the Privolzhskaya Lesostep Nature Reserve and the species lists for each segment were compiled (Polchaninova, 2008, 2015a, b, 2020). In total, 273 spider species of 23 families were recorded from the reserve. The segments are located in four administrative districts of the region. The present paper provides an annotated list of 71 spider species recorded for the first time from the Lunino District. The material was collected by pitfall trapping in 2004 and 2005 in five habitats in the Nature Monument Solontsovaya Steppe: meadow steppe on the chernozem soil on a gentle slope (33 species), steppe on the clayey soil on a steep gully slope (33 species), steppe on the solonetz soil on a gentle slope (43 species), sand and clay quarry (28 species), and bank of a pond (29 species). The most abundant was the spider assemblage of the meadow steppe (736 individuals) dominated by Pardosa fulvipes (62 % of total spiders collected in the habitat). Other spider assemblages were less abundant (minimum 243 individuals on the pond bank and maximum 324 individuals in the solonetz steppe), and their dominance structure was more uniform. The dominant complexes consisted of Gnaphosa lugibris, Haplodrassus signifier and Xerolycosa miniata in the clayey steppe (53 % of total spiders in the habitat), X. miniata, P. fulvipes, P. palustris, and P. agrestis in the solonetz steppe (60 %), X. miniata and P. fulvipes in the quarry (57 %), and P. fulvipes, P. palustris, and Diplostуla concolor on the pond bank (63.5 %). Thus, Pardosa fulvipes and Xerolycosa miniata were the most numerous species at the study site. A high abundance of both species was also observed in the Borok segment of the Privolzhskaya Lesostep Nature Reserve, which suggests similarity of ecological conditions in the grassland habitats of both localities. One species, Mastigusa arietina, is new to the Penza Region. Taking into account 40 species recorded by М. Pyatin (1988) but absent from our collection, the spider fauna of the Penza Region numbers 313 species of 27 families.

天然和人工固沙灌木林蜘蛛和甲虫分布与环境因子的关系

天然和人工固沙灌木林蜘蛛和甲虫分布与环境因子的关系

Ground spiders (Arachnida, Araneae) associated with urban forest fragments in southern Amazon

Abstract: Forest fragments in urban areas comprise important habitats for a wide variety of species, however, conservationist policies for their maintenance and conservation are still incipient. This study examined the richness and abundance of the ground-spider assemblage in five forest fragments, with areas ranging between 18.5 and 103.98 ha, in the urban perimeter of Sinop, northern Mato Grosso State, southern Amazon region of Brazil. Sampling was carried out using the mini-Winkler extractor and pitfall traps in the dry (July) and rainy (November) seasons of 2017. All fragments were characterized in relation to the area and the Index of Biotic Integrity (IBI), to assess the effect of these variables on richness and abundance of soil spider assemblage. A total of 653 spiders were sampled, corresponding to 25 families and 52 species. Salticidae, Theridiidae, Lycosidae, Linyphiidae, Oonopidae and Symphytognathidae were the most abundant families (63.3% of the total sample). The assemblage was characterized by the dominance of hunting spiders (393 ind.; 60.2%) over web-building spiders (260 ind.; 39.8%). Greater spider abundance and richness was obtained during the rainy season (517 ind.; 79.2%; 41 spp.) as compared with the dry season (136 ind.; 20.8%; 24 spp.). Only 13 species occurred in dry and rainy season. Two species were recorded for the first time in the Amazon region, namely, Anapistula aquytabueraRheims &amp; Brescovit, 2003 (Symphytognathidae) and Opopaea concolor (Blackwall, 1859) (Oonopidae). Species richness was not affected by IBI and area of fragment. Although the statistical model is not significant, species richness increases slightly with IBI and area of fragment. Similarly, abundance of spiders was not affected by IBI and area of fragment. Regardless of the area size, all evaluated forest fragments showed a low and regular IBI, demonstrating that these habitats have suffered with the pressures inherent from the urban perimeter, including the constant expansion of human occupation as well as misuse by the population. Nonetheless, these same fragments revealed considerable richness of species of ground spiders and can thus be categorized as important habitats for the maintenance of regional biodiversity. Therefore, action strategies must be set out to ensure their conservation.

Drivers of the beta diversity of spider assemblages in southern Brazilian temporary wetlands

1. The composition of local assemblages is assembled by an interplay of species sorting, mass effects and dispersal limitation processes. The contributions of assembly processes to metacommunity structure can change with ecosystem type and specificities of the study area. Spider composition is influenced by environmental features such as habitat structure and climate, and also by spatial distances between patches. However, little is known about the roles of assembly processes in spider metacommunity structure in wetlands.2. The beta diversity patterns of spider assemblages were assessed in 24 temporary wetlands distributed along a latitudinal gradient in southern Brazil. The study also assessed the individual correspondence of beta diversity (and its turnover and richness components) with dissimilarities in habitat structure and climate, as well as with geographic distances, using Mantel and partial Mantel correlation tests and multivariate correlograms.3. Turnover was the most important component of spider beta diversity. Mantel tests detected significant correlations of spider beta diversity with habitat structure. Partial Mantel tests detected significant relationships only between spider beta diversity (and the richness component) and geographic distances. Additionally, spider composition was more similar than chance on smaller scales.4. These results evidenced a complex interplay of assembly processes explaining spider metacommunity structure in temporary wetlands. Although species‐sorting processes associated with habitat structure were important in structuring local spider composition, mass effects and dispersal limitation across climatic zones played an important role on a broader scale.

Summer fire in steppe habitats: long-term effects on vegetation and autumnal assemblages of cursorial arthropods

Abstract Being an essential driving factor in dry grassland ecosystems, uncontrolled fires can cause damage to isolated natural areas. We investigated a case of a small-scale mid-summer fire in an abandoned steppe pasture in northeastern Ukraine and focused on the post-fire recovery of arthropod assemblages (mainly spiders and beetles) and vegetation pattern. The living cover of vascular plants recovered in a year, while the cover of mosses and litter remained sparse for four years. The burnt site was colonised by mobile arthropods occurring in surrounding grasslands. The fire had no significant impact on arthropod diversity or abundance, but changed their assemblage structure, namely dominant complexes and trophic guild ratio. The proportion of phytophages reduced, while that of omnivores increased. The fire destroyed the variety of the arthropod assemblages created by the patchiness of vegetation cover. In the post-fire stage they were more similar to each other than at the burnt plot in the pre- and post-fire period. Spider assemblages tended to recover their pre-fire state, while beetle assemblages retained significant differences during the entire study period.

Effects of reindeer grazing and recovery after cessation of grazing on the ground-dwelling spider assemblage in Finnish Lapland.

The effect of reindeer Rangifer tarandus L. grazing on the ground-dwelling spider assemblage in Northern Finland was studied. Changes in species richness, abundance and evenness of spider assemblages were analyzed in relation to changes in vegetation and environmental factors in long term grazed and ungrazed sites as well as sites that had recently switched from grazed to ungrazed and vice versa. Grazing was found to have a significant impact on height and biomass of lichens and other ground vegetation. However, it seemed not to have an impact on the total abundance of spiders. This is likely caused by opposing family and species level responses of spiders to the grazing regime. Lycosid numbers were highest in grazed and linyphiid numbers in ungrazed areas. Lycosidae species richness was highest in ungrazed areas whereas Linyphiidae richness showed no response to grazing. Four Linyphiidae, one Thomisidae and one Lycosidae species showed strong preference for specific treatments. Sites that had recovered from grazing for nine years and the sites that were grazed for the last nine years but were previously ungrazed resembled the long term grazed sites. The results emphasize the importance of reindeer as a modifier of boreal forest ecosystems but the impact of reindeer grazing on spiders seems to be family and species specific. The sites with reversed grazing treatment demonstrate that recovery from strong grazing pressure at these high latitudes is a slow process whereas reindeer can rapidly change the conditions in previously ungrazed sites similar to long term heavily grazed conditions.

Even the smallest habitat patch matters: on the fauna of peat bogs

Peat bogs are highly endangered and very sensitive habitats in Central Europe. Their high water table, acidity and characteristic climate determine their specialized flora and fauna with numerous rare species. Peat bogs are threatened by soil erosion and nutrient infiltration due to forestry management or grazing. Several small, natural peat bogs exist in the Carpathians, mainly covered with birch and pine forests. Here we assessed the effect of geological location, peat bog size and tree species on the spider fauna. We collected spiders with pitfall traps in eight peat bogs in Eastern Transylvania. We identified several species of high nature conservation value, regarded to be rare in the Central-European fauna. We found higher species richness, abundance and diversity in birch forests than in pine forests. The open canopy of birch forests may allow open habitat specialists to occur in high densities in these forests. Species composition was affected by geological location, indicating that the regional fauna of peat bogs in different mountain ranges are isolated. However, we found no significant effect of habitat area on spider assemblages, the valuable tyrphophilic spider fauna was present even in the smallest peat bog. Peat bog spider fauna requires specific habitat conditions, we suggest that preserving hydrological properties and water quality even in the smallest bogs would conserve the specialized fauna.

Can native plantings encourage native and beneficial invertebrates on Canterbury dairy farms?

ABSTRACTFarming intensification negatively effects native habitat and associated biodiversity in New Zealand. Planting native species around field margins has been proposed as a means of restoring biodiversity within this highly modified landscape. To test this hypothesis, we collected invertebrates on a dairy farm at Lincoln, Canterbury, in three habitat types: native plantings in field corners, native plantings along a double fence line, and pasture. Invertebrates were collected from pitfall traps, yellow pan traps, wooden discs and leaf litter samples were collected from the sites over summer. Assemblages of spiders, flying insects, slugs and litter mites in the planted areas had distinct compositions compared with those found in adjacent pasture. Species richness of native spiders was increased in the planted areas compared with adjacent pasture, as was the abundance of ecosystem service providers, such as honeybees, parasitoid wasps and hoverflies. Exotic slugs were significantly more abundant under discs in pasture than in planted areas. However, not all native or beneficial invertebrates responded positively to the planted areas. Further research is required to examine whether these results are repeatable at other locations, if invertebrate assemblages at this location develop further over time, and to evaluate whether any perceived benefits of these service providers can be quantified in terms of meaningful endpoints such as reduced pest levels and/or increases in yield.