Ground-dwelling Spiders Research Articles

Ground-dwelling arthropod community response to native grassland conversion in a temperate desert of northwestern China

Oases are common in desert regions of northwestern China and are major sites for human settlement. The implementation of oasis conservation planning has led to afforestation with appropriate shrubs and trees in the native grasslands surrounding inhabited oases. However, little is known about how this Land use change from native grassland to shrub and tree plantations influences the composition of ground-dwelling arthropod communities and the performance of their different trophic groups. To address this, we measured activity density, taxon richness, and relative abundance of four different ground arthropod trophic groups (spiders, beetle predators, beetle herbivores, and beetle detritivores) and several environmental variables affecting arthropod distributions (vegetation cover, ground temperature, soil moisture, soil properties, and leaf litter) along an experimentally established land use change gradient of a mature shrub (Haloxylon ammodendron) planation, a mature poplar (Populus gansuensis) plantation and a mature pine (Pinus sylvestris) plantation, as well as a native grassland from which all cultivated systems were converted. We found that converted shrub plantation had much lower activity density of predatory, herbivorous, and detritivorous beetles; similar activity density of spiders; and similar taxa richness of all four trophic groups relative to the native grassland. However, converted forest plantations regardless of tree species had much higher activity density of spiders, lower activity density of the three beetle groups, much higher richness of predatory beetles, and lower richness of herbivorous and detritivorous beetles. We also found a change in the composition of the ground arthropod community that was largely driven by changes in ground temperature and leaf litter mass. We conclude that conversion of native grassland to shrub and tree plantations can significantly affect ground-dwelling arthropod communities, reducing the activity of ground-dwelling beetle assemblages while increasing that of ground-dwelling spider assemblages. These findings are important for conserving native arthropod diversity in desert ecosystems.

Functioning of Ecotones — Spiders and Ants of Edges Between Native and Non-Native Forest Plantations

Habitat edges are regarded as important components of heterogeneous landscapes. Diverse theories exist about the diversity and functional role of edges, and no generalisation have been possible so far, thus case studies are important for better understanding the landscape scale processes. Forest management highly modified the structure and tree species composition of the European forests. The sylvicultural intensification resulted in the rise of the proportion of non-native, intensively managed forest stands. In the present study we explore the response of spider and ant assemblages to forest stand type and the edge effect between native poplar and nonnative conifer plantations in Hungary. We applied pitfall traps to sample the ground-dwelling spiders and ants. Four plots consisting of the two forest types and the transition zones between them were selected. Five transects for each replicated plot were sampled. We identified the significant indicator species of the different habitat types. We found significant differences in the species richness (i.e. number of species) of ants and spiders of the different habitat types. We detected intermediate spider species richness at the edge indicating that edges separate a higher quality habitat from one that has lower resource quality; however, the species richness of ants was the highest at the edge and did not differ between the two forest types. The positive impacts of edge was found due to presence of generalist and grassland species at the edge and presumably edges separate patches that provide complementary resources also increasing the number of ant species.Our results indicate that forest type affects the species compositions of ground-dwelling spiders and ants. Our study also shows that habitat type had a major effect on the species richness and composition of spider and ant assemblages, suggesting that local forestry management plays a crucial role in preserving the native invertebrate fauna of forests.

The effects of habitat parameters and forest age on the ground dwelling spiders of lowland poplar forests (Hungary)

Forest management has highly modified the structure of the European forests. Harvesting and post-harvest regeneration leads to a simplified forest structure. Our main objective was to detect the effects of habitat structure and forest age on the ground-dwelling spider diversity and assemblage composition of poplar forests at the Hungarian Great Plain. Our results demonstrate that the rarefaction diversity and the number of forest specialists closely correlated with the structural parameters of the forest floor, however, the age and canopy closure did not influence these parameters. According to redundancy analysis, the composition of spider assemblages was determined solely by habitat structure, with habitat structure having a major effect on the species composition and diversity of spider assemblages. A direct effect of forest age on the spider assemblages was not detected, due to the presence of different habitat types in the surrounding landscape, which may serve as suitable habitats for source-populations of spiders with different habitat requirements. Our results highlight the importance structural complexity of forests for maintaining forest spider diversity and preserving the regional species pool of spiders.

Spider (O: Araneae) Responses to Fire and Fire Surrogate Fuel Reduction in a Piedmont Forest in Upstate South Carolina

The two forest-management practices of prescribed burning and thinning are techniques used to reduce heavy fuel loads that have resulted from years of fire suppression. Therefore, the National Fire and Fire Surrogate (NFFS) study was conducted to determine the effects of prescribed burning and thinning on different environmental factors. This study was conducted in the Clemson University Experimental Forest in South Carolina, one of the 13 NFFS sites in the United States, and examined the impacts of these management practices on spider populations. We used pitfall traps to sample ground-dwelling spiders to determine if changes in population levels had occurred one year following implementation of these practices. We collected a total of 1220 specimens of Araneae, representing 13 families. Results indicated that by 1-year post-treatment, spider populations had recovered following the initial (2001) burning and thinning. However, in 2002, when we compared the first post-burn samples to pre-burn samples in thin burn plots, we found a significant decrease in the mean abundance of Agelenidae and Linyphiidae after the prescribed burn.

Ground-dwelling spider diversity in rare European oak and yew woodlands and the impact of grazing

In Ireland only 2 % of the total land area is native woodland, which tends to be small and fragmented. Killarney National Park in south-west Ireland contains the most extensive semi-natural woodland in the country, and includes oak (Quercus petraea) and yew (Taxus baccata) woodlands which are internationally protected. Here, over-grazing by large populations of red deer (Cervus elaphus) and Asian sika deer (Cervus nippon) have lead to changes in overstory and understory vegetation species composition and structure. This study presents the first description of ground-dwelling spider fauna in the rare woodlands of Killarney National Park and asked (1) do these rare woodlands support rare or specialist species, (2) does deer grazing have an effect on spider abundance, richness and species composition in the park, (3) what management recommendations can be made for deer in the park? Active ground-dwelling spiders were sampled in the oak and yew woodlands of the park by pitfall trapping within deer-proof exclosures and adjacent grazed controls. Four spider species classified as vulnerable were collected from these woodlands: Agyneta subtilis occurred in the oak and yew woodlands but Saaristoa firma, Tapinocyba insecta and Walckenaeria dysderoides were collected only in the oak woodland. Killarney National Park may be important for five species, not typically found in plantation forests, which rely on nationally scarce habitats. Deer grazing was linked with decreased ground-dwelling spider abundance and species richness in the oak woodland by reducing structural diversity of the habitat. Fewer effects of grazing were detected in the yew woodland, possibly due to increased culling in the area. Results provide evidence that controlling deer grazing is important for woodland biodiversity in Killarney National Park. Incorporating deer into woodland management in the park is recommended to maintain low grazing levels which will prevent woodland closure and maintain ground vegetation diversity.

Assessing spider diversity on the forest floor: expert knowledge beats systematic design

The design of sampling schemes affects the results of biodiversity inventories. As an approach for quantifying the implications of such effects, we compared data on spider communities sampled in a beech-dominated forest floor habitat by 1) a regular grid of pitfall traps (systematic design) and 2) an expert-based distribution of traps (stratified design). We tested whether the two designs would lead to similar conclusions about the diversity and composition of ground-dwelling spider communities. Estimates of species richness, rarefied species richness and activity density calculated per trap were significantly higher in the stratified than in the systematic design. The community composition based on the presence or absence of sampled species or based on log-transformed activity densities differed significantly. Most of the dissimilarity between the community estimates of the two designs was attributable to three species, with Pardosa saltans Topfer-Hofmann 2000 being more common in traps of the stratified design and Tenuiphantes zimmermanni (Bertkau 1890) and Walckenaeria cuspidata Blackwall 1833 being more frequently observed in traps of the systematic design. Our study suggests that a stratified sampling design is better suited for inventory surveys of spider communities of forest-floor habitats, as trap locations of this design reflect specific habitat needs. It is important to note that inventories are a major field for the application of such designs and that greater care is needed for the application of inferential statistics. For example, the non-randomness that is caused by expert selection of sampling sites may violate fundamental assumptions of simple linear models.

Spiders in motion: demonstrating adaptation, structure-function relationships, and trade-offs in invertebrates

Evolutionary history and structural considerations constrain all aspects of animal physiology. Constraints on invertebrate locomotion are especially straightforward for students to observe and understand. In this exercise, students use spiders to investigate the concepts of adaptation, structure-function relationships, and trade-offs. Students measure burst and endurance performance in several taxonomic families of spiders whose ecological niches have led to different locomotory adaptations. Based on observations of spiders in their natural habitat and prior background information, students make predictions about spider performance. Students then construct their own knowledge by performing a hands-on, inquiry-based scientific experiment where the results are not necessarily known. Depending on the specific families chosen, students can observe that web-dwelling spiders have more difficulty navigating complex terrestrial terrain than ground-dwelling spiders and that there is a trade-off between burst performance and endurance performance in spiders. Our inexpensive runway design allows for countless variations on this basic experiment; for example, we have successfully used runways to show students how the performance of heterothermic ectotherms varies with temperature. High levels of intra- and interindividual variation in performance underscore the importance of using multiple trials and statistical tests. Finally, this laboratory activity can be completely student driven or standardized, depending on the instructor's preference.

The influence of fire disturbance on the biotype structure and seasonal dynamics of ground-dwelling spider on Cangshan Mountain, Yunnan Province

The influence of fire disturbance on the biotype structure and seasonal dynamics of ground-dwelling spider on Cangshan Mountain, Yunnan Province

Ground-dwelling spider (Araneae) and carabid beetle (Coleoptera: Carabidae) community assemblages in mixed and monoculture stands of oak (Quercus robur L./Quercus petraea (Matt.) Liebl.) and Scots pine (Pinus sylvestris L.)

A mixed tree species composition is frequently proposed as a way to increase habitat heterogeneity and support greater biodiversity in commercial forests. However, although international forest policy is increasingly advocating stands of mixed tree species, there is evidence to question the biodiversity benefits conferred by such forests. Using active ground-dwelling spiders and carabid beetles as biodiversity indicator taxa, we investigated the effect of forest stand composition on spider and carabid beetle community structure and composition. We conducted pitfall trapping in the summer of 2011 in 42 plantation forest stands across three different geographical regions in the UK and Ireland. Three common plantation forest stand types were examined: oak monocultures, Scots pine monocultures, and intimate Scots pine and oak mixtures (oak ⩽60% cover). Forest stand type had a weak effect on spider and beetle species richness, with no significant differences in mixed stands compared with monocultures. There were few differences in species composition between the stand types in each region and indicator species analysis found few species specifically affiliated with any of the forest stand types. Land use history is hypothesised to have contributed, at least in part, to the observed important regional differences in spider and beetle assemblages. Our results do not support the perception that intimate mixtures of dominant tree species benefit biodiversity in plantation forest stands. Further research is required to determine the optimum percentages and planting patterns required for mixtures of canopy tree species in order to support forest biodiversity.

Effect of habitat type and pitfall trap installation on captures of epigaeic arthropod assemblages in the boreal forest

AbstractIt is unrealistic to achieve high-resolution biodiversity inventories required to support local conservation strategies over large areas; however, benchmark associations between arthropods and ecosystem classification can support landscape scale biomonitoring. We investigated habitat associations of ground-dwelling spiders (Araneae), staphylinid beetles (Coleoptera: Staphylinidae), and carabid beetles (Coleoptera: Carabidae) in three forest ecosystems in northwestern Alberta, Canada and also studied the effect of variation in depth of pitfall trap installation on catch. Composition and diversity of all three taxa were correlated with the ecosystem classification map, and 20 species were strong indicators of particular habitats. The black spruce (Picea mariana(Miller) Britton, Sterns, and Poggenburg; Pinaceae) bog supported fewer species and individuals of beetles but this trend was not observed for spiders because of natural history traits associated with their performance in this environment. Pitfall trapping biases were constant among habitats enabling proper comparison of ground-dwelling invertebrate assemblages. Three species of beetles (Agonum retractumLeConte (Coleoptera: Carabidae),Pterostichus brevicornis(Kirby) (Coleoptera: Carabidae), andQuedius veloxSmetana (Coleoptera: Staphylinidae)) were disproportionally active beneath the soil surface, as catches were greater in pitfall traps with the lip situated 15–25 cm below the soil surface. Thus, even highly standardised trap placement will influence the concept of biodiversity achieved through pitfall trapping, because some target organisms are disproportionately active in subterranean zones.

Microhabitat heterogeneity in temperate forests: is distance to stems affecting ground-dwelling spider communities?

Spiders contribute essentially to the arthropod community of forests and are known to be distributed in non-random pattern according to environmental, structural, competitive, and predacious conditions. The aim of the study was to investigate the effects of the distance to trees on the distribution pattern of soil-dwelling spiders. We verified the hypothesis that stem-close and stem-distant microhabitats differ with respect to taxonomical and ecological characteristics of spider assemblages, hence, functional significance on a small spatial scale. Ground-dwelling spiders were collected with pitfall traps in positions close (20–30 cm) and distant (2 m) to the stem bases in mature forests of different stand types (spruce, Douglas fir, beech-spruce, oak-beech). To identify significant drivers of spider assemblage composition, environmental parameters were assessed in relation with the arrangement of pitfall traps. The study documented significant variability in the composition of spider assemblages of stem-c...

The habitat-specific effects of highway proximity on ground-dwelling arthropods: Implications for biodiversity conservation

The total length of highways worldwide has increased continuously over recent decades. Highways and their roadside verges may substantially affect species dispersal, and the ecological effects of highways often extend to neighbouring areas. This study investigated the effects of highways on assemblages of ground-dwelling arthropods in neighbouring forest and open habitats. In total, 24 sites within five highway segments situated in the Czech Republic were sampled using transects of pitfall traps placed at increasing distances (0, 50 and 100m) from the edge of highway verges. The total catch size and species richness of ground-dwelling spiders and beetles varied more strongly with distance from the highway edge in forest habitats than in open habitats. Species composition of both spiders and beetles was significantly affected by distance from the highway edge in open habitats as well as in forest habitats. In general, the species richness of forest specialist beetles (but not of spiders) was negatively affected by highway proximity in forested sites, whereas habitat generalists and open habitat specialists (both spiders and beetles) benefited from proximity to a highway in both forest and open habitats. Our results indicate that highway verges may potentially enhance local assemblages of ground dwelling spiders and beetles because they provide suitable sites (in intensively managed open landscapes) or dispersal corridors (in forested landscapes) for habitat generalists and open habitat specialist species. However, negative effects on forest specialists must also be considered, especially in landscapes with little forest. The landscape context should be given substantial consideration in future decisions about highway location because possible threats to forest specialists and benefits for other species must be recognised and balanced.

Effects of prescribed burning and harvesting on ground-dwelling spiders in the Canadian boreal mixedwood forest

The ‘Natural Disturbance Paradigm’ for forest management seeks to meet conservation goals by modeling industrial harvest in fire-driven forest systems on patterns associated with wildfire. Fire suppression and increased forest harvesting may have detrimental effects on biodiversity, and therefore prescribed burning is suggested to retain legacies of wildfire not emulated under natural disturbance based approaches. The merits of this approach are being tested in the EMEND experiment in the Canadian boreal mixedwood forest. We compared responses of ground-dwelling spiders between sites subjected to prescribed post-harvest burning and retention harvest during three seasons during the first 7 years after disturbance. Overall, 38,661 adult spiders representing 190 species were collected. Estimated species richness was highest in undisturbed sites in all 3 years. Burning had the strongest negative effect on species richness 1–2 years after treatment; however, richness was higher in burns than in harvested sites 5–6 years post-disturbance. Species turnover was highest within controls but tended to increase over time between burned and harvested plots. Lower turnover in burned and harvested sites may reflect habitat homogenization by disturbance, suggesting a management and conservation challenge in relation to naturally disturbed and undisturbed areas. Species were grouped into disturbance-specialists, disturbance-tolerant, disturbance-generalists and generalists; 22 species were significant indicators for untreated sites, 18 for the burn and three for the harvest treatments. No major differences were observed in the spider fauna between harvested and burned areas within the first 6–7 years post-disturbance, and little evidence of recovery toward the pre-harvest fauna was evidenced. However, long term experiments may improve understanding of natural disturbance processes and improve management of boreal forests.

Facilitation of ground-dwelling wolf spider predation on mirid bugs by horizontal webs built byTetragnathaspiders in organic paddy fields

Trait-mediated effects of predators can impact prey population dynamics by affecting prey behavior. The mirid bug Stenotus rubrovittatus (Matsumura) (Hemiptera: Miridae), a major insect pest in Japanese rice production, usually remains in the upper layer of paddies to feed on rice ears. However, the mirids are frequently trapped by horizontal webs of Tetragnatha spp. spiders, which are highly abundant in organic rice paddies, and fall to the bottom layers of paddies where they are preyed upon by ground-dwelling predators. It is hypothesized that Tetragnatha spp. spiders facilitate bug predation by wolf spiders through trait-mediated effects, in which their horizontal webs force the bugs onto or near the ground and thereby into the hunting zones of wolf spiders. Molecular gut-content analysis of 619 wolf spiders coupled with field measurements revealed that the number of wolf spiders that tested positive for mirid bug predation increased significantly with the density of Tetragnatha spp. spiders in the paddies. We also observed a positive relationship between Tetragnatha spp. abundance and total cover by their webs in paddies. We identified the potential for an unexpected interaction between an herbivorous insect pest and ground-dwelling spiders that usually inhabit different microhabitats in paddy fields by focusing on trait-mediated effects of webs built by Tetragnatha spp. Because spider webs occupy a certain proportion of the available space in terrestrial ecosystems, consideration of trait-mediated effects on interactions between flying insects and other predators may lead to a better understanding of local food webs.

云南苍山火烧迹地不同恢复期地表蜘蛛群落多样性

We investigated dynamics of ground-dwelling spider diversity after fire in mixed broadleaf-conifer forest in Cangshan Mountain,Yunnan Province.Sampling of ground-dwelling spider diversity was carried out in six sites(2,10,18,23 and 33 years after fire,and one unburned site) from January 2009 to December 2009,based on a 'space-for-time substitution' sampling by pitfall trap.We found that(1) species composition and relative abundance changed dramatically across the six different fire succession sites;(2) the abundance of ground-dwelling spider in the 10 year site times was significantly higher than other sites,and there was no significant difference in species richness among the six sites;(3) ground-dwelling spider community succession could be divided into 3 stages by PCoA analysis: 2 years after fire,10 years after fire,18-33 years after fire;(4) Indicator Species Analysis base on R language package 'labdsv' show: Sibianor sp.1 et al.was the indicator of first stage,Lycosa graham et al.was the indicator of second stage,Xysticus sp.2 et al.was the indicator of third stage,Leptoneta sp.1 et al.was the indicator of control.Fire disturbance and subsequent succession changed the ground-dwelling spider community.The habitat selection of indicator could indicate the variability of different restorations post-fire forest.The ground spider community in the oldest of the burned sited does not yet resemble the community in the unburned site indicating that the restoration of the ground spider community for Cangshan Mountain takes longer than three decades.

THE IMPORTANCE OF YOUNG PLANTATION FOREST HABITAT AND FOREST ROAD-VERGES FOR GROUND-DWELLING SPIDER DIVERSITY

The potential of forest roads to enhance habitat diversity within plantation forests is an important conservation issue. If properly managed, these open spaces allow structurally diverse vegetation to grow at the road-verges, which may support greater invertebrate abundance and species richness, increasing overall forest biodiversity. We investigated spider diversity along road edges in young plantation forests in Ireland, the influence of road-verge vegetation and the consequences of doubling the standard forest road-width currently used in Ireland. Active ground-dwelling spiders were studied in eight Sitka spruce (Picea sitchensis) plantations using pitfall trapping one year after planting and five years after planting. A total of 16,741 spiders were caught, from which 141 species were identified from 14 families. Ten spider species of conservation importance were found in the road-verges demonstrating their importance as habitats for spider diversity. We found no difference in ground-dwelling spider diversity between road-verge and forest interior plots at this stage in the rotation. We found no advantage or disadvantage of increasing the road-width of forest roads for ground-dwelling spider diversity of young plantation forests. The findings of this study are discussed in the context of the management of plantation forests for biodiversity conservation and associated forest policy development.

The Importance of Young Plantation Forest Habitat and Forest Road-Verges for Ground-dwelling Spider Diversity

The potential of forest roads to enhance habitat diversity within plantation forests is an important conservation issue. If properly managed, these open spaces allow structurally diverse vegetation to grow at the road-verges, which may support greater invertebrate abundance and species richness, increasing overall forest biodiversity. We investigated spider diversity along road edges in young plantation forests in Ireland, the influence of road-verge vegetation and the consequences of doubling the standard forest road-width currently used in Ireland. Active ground-dwelling spiders were studied in eight Sitka spruce (Picea sitchensis) plantations using pitfall trapping one year after planting and five years after planting. A total of 16,741 spiders were caught, from which 141 species were identified from 14 families. Ten spider species of conservation importance were found in the road-verges demonstrating their importance as habitats for spider diversity. We found no difference in ground-dwelling spider diversity between road-verge and forest interior plots at this stage in the rotation. We found no advantage or disadvantage of increasing the road-width of forest roads for ground-dwelling spider diversity of young plantation forests. The findings of this study are discussed in the context of the management of plantation forests for biodiversity conservation and associated forest policy development.

IN THIS ISSUE

IN THIS ISSUE Cite asfollows: Osborne B.2013In this issue. Biology andEnvironment : Proceedings of the Royal Irish Academy 113B (3), i-iii; DOI:103318/ BIOE.2013.19. FEEDING PREFERENCES OF THE 'ONE DAY FLY' Mayflies, the'oneday'fly, so named because ofthe short lifespanoftheadults, area common feature ofmanyofouraquaticecosystems. Theseancient insects, whichhavea fossil record that extends back approximately 300 million years, arean important foodsource for a range offish species and,inturn, a keycomponent oftheaquaticfoodweb. Recent reports indicate,however,thattheyare under threat, mainly from pollution, with6 outofa total of 33 Irishspeciesconsidered endangered. Their susceptibility to pollution is in partrelated to the factthatthelarval, longer-lived stage, survives on lake or riverbeds where pollutants are often concentrated. Mayflies, however,varyin their susceptibility to pollution,althoughthe causal factors governing thisvariation are stillpoorly understood. Wögerbauer and Kelly-Quinn,in thisissue,examine thepossibility thatdifferences infoodpreference maycontribute tothis. Although oftenthoughtto be dependenton algae and diatoms,mayflies can utilisea variety of food sources. Of thethree mayfly speciesexamined by Wögerbauer and Kelly-Quinn, two (Ecdyonurus venosus and E. insignis ), which are sensitive to nutrient enrichment, arespecialised detritus feeders, whilst theother (Baetis rhodaní ), isa moregeneralist feeder and is notparticularly sensitive to nutrient enrichment. The authors therefore arguethatthe ability toutilise a variety offoodsources conveys a greaterflexibility for survivalunder polluted, nutrient-enriched conditions. VALUING THE WOODS AND THEIR HABITATS Threerelated papers dealwith various aspects ofthe role of woodlandsand forests in biodiversity conservation bothnowandinthefuture. The first bySharkeyetal.9in thisissueaddresses thelikely impact ofclimate change on woodland species and how thismaybe important forthe future conservation of woodlandhabitats in Ireland.The secondby Fuller et al., in thisissue, examines theimportance ofplantation forests, longthought to be of low or uncertain biodiversity value,on ground dwelling spider diversity. The lastone by Irwinetal.9inthisissue,assesses thevalueofIrish forests as a habitatforspeciesof conservation concern. Sharkey etal. show,usingmodelprojections, that climate change willresult inwinners andlosers, asfar aswoodland species areconcerned, with both largereductions as wellas largerangeexpansions beingidentified. Not all speciesof current conservation concern maybe endangered, as issometimes assumed, andsomemayactually benefit from theeffects ofclimate change.Critically, however, theseresults are heavilydependent on dispersal, whichwas treated rather simply in theirmodel; whenlimited dispersal capability was used as an input therange ofallspecies wasreduced. Thisfact willclearly haveimportant consequences forany future management interventions that areaimedat conserving woodland species. Roadswithin plantation forests could,because of theirgreater structural diversity, facilitate increased biodiversity in whatotherwise is a rather uniform vegetation cover,providing opportunities fora rangeoflesscommonspecies.WhileFuller etal. found tenspecies ofground dwelling spiders of conservation value thatwere uniqueto road verges,overall spiderbiodiversity was similar betweenroadvergesand forest stands and independent ofroadwidth.Forest roadscouldthereforeprovide an important refuge forimportant or rarespeciesthatwouldotherwise be absent from. afforested areas. Irwin et al. also examinethe questionof whetherIrishforests could providehabitats for plants,birdsand invertebrates of conservation concern, in a comparison of semi-natural woodlandsand plantation forests. While semi-natural woodland habitatswere associatedwith the greater numbers of speciesof conservation concern ,plantation forests do support some nationally rareor threatened speciesand may be of particular importance in areasthathave experienced the loss of naturalforestecosystems. Overall,theworkemphasises theimportance of semi-natural forest systems forthemaintenance of biodiversity, particularly in intensively managed landscapes. RECREATING THE PAST A majorconservation goalinmany countries isthe restoration oflandscapes associated withplantation DOI:103318/BIOE.2013.19 Biology andEnvironment: Proceedings oftheRoyalIrish Academy, Vol.113B, No.3,i-iii (2014).q RoyalIrish Academy i Biology and Environment forestry, whichhasbeendominated byonespecies, Sitkaspruce. In manycasesthesewereplanted on former semi-natural/ancient woodlands orin areas withsignificant biodiversity, wheretheimpacts of humanintervention were small.Tree removal, particularly in areaswherestanddensity is low is an obviousapproach,but can the characteristic vegetation cover associated withthe pre-harvest conditions be created?This will depend on a number offactors, including thelongevity ofseeds in the seed bank and the opportunities for recruitment of speciesthatmayhave been lost during theperiodof plantation forestry. Cooper and McCann, in this issue investigated the effects of Sitkaspruceremoval on areasformerly associated withbroadleaf woodlandand a mixed grassland-hedgerow farmed landscape.Based on thepost-harvest analysis there aregoodgrounds for expecting significant initial recovery ofthevegetation , but, in the longer term,this may be dependenton the rapid developmentof an extensive treecanopy.While post-harvest birch numbers werehigh,there weresmallnumbers of othertreespeciespresent and recovery of these would be dependenton significant recruitment fromoutsidetheareaof investigation, or would require management intervention. Clearly our capability to recreate pastlandscapes willdepend critically on thebiodiversity oftheecosystem prior to...

A faunistic study on ground-dwelling spiders (Araneae) in the Tirana district, Albania

Spiders from the Tirana district of Albania were investigated. Currently, 78 species from 24 families and a colle- ction of 400 specimens from January to August 2010 were recorded for Tirana. A total of 32 new records for the Albanian fauna are included in the present paper. Agraecina lineata (Simon, 1878) is the first record for the Balkan Peninsula. Saitis graecus Kulczynski, 1905 was known before only from Greece and Bulgaria. Presently, 373 spider species are known for Albania.

Species Richness-Environment Relationships of European Arthropods at Two Spatial Grains: Habitats and Countries

We study how species richness of arthropods relates to theories concerning net primary productivity, ambient energy, water-energy dynamics and spatial environmental heterogeneity. We use two datasets of arthropod richness with similar spatial extents (Scandinavia to Mediterranean), but contrasting spatial grain (local habitat and country). Samples of ground-dwelling spiders, beetles, bugs and ants were collected from 32 paired habitats at 16 locations across Europe. Species richness of these taxonomic groups was also determined for 25 European countries based on the Fauna Europaea database. We tested effects of net primary productivity (NPP), annual mean temperature (T), annual rainfall (R) and potential evapotranspiration of the coldest month (PETmin) on species richness and turnover. Spatial environmental heterogeneity within countries was considered by including the ranges of NPP, T, R and PETmin. At the local habitat grain, relationships between species richness and environmental variables differed strongly between taxa and trophic groups. However, species turnover across locations was strongly correlated with differences in T. At the country grain, species richness was significantly correlated with environmental variables from all four theories. In particular, species richness within countries increased strongly with spatial heterogeneity in T. The importance of spatial heterogeneity in T for both species turnover across locations and for species richness within countries suggests that the temperature niche is an important determinant of arthropod diversity. We suggest that, unless climatic heterogeneity is constant across sampling units, coarse-grained studies should always account for environmental heterogeneity as a predictor of arthropod species richness, just as studies with variable area of sampling units routinely consider area.