TY - GEN A1 - Arvidsson, Fredrik A1 - Jonsson, Lars J. A1 - Birkhofer, Klaus T1 - Geographic location, not forest type, affects the diversity of spider communities sampled with malaise traps in Sweden T2 - Annales Zoologici Fennici Y1 - 2016 U6 - https://doi.org/10.5735/086.053.0410 SN - 0003-455X SN - 1797-2450 VL - 53 IS - 3-4 SP - 215 EP - 227 ER - TY - GEN A1 - Birkhofer, Klaus A1 - Arvidsson, Fredrik A1 - Ehlers, D. A1 - Mader, Viktoria A1 - Bengtsson, Janne A1 - Smith, Henrik G. T1 - Landscape complexity and organic farming independently affect the biological control of hemipteran pests and yields in spring barley T2 - Landscape Ecology Y1 - 2016 U6 - https://doi.org/10.1007/s10980-015-0263-8 SN - 0921-2973 SN - 1572-9761 VL - 31 IS - 3 SP - 567 EP - 579 ER - TY - GEN A1 - Arvidsson, Fredrik A1 - Addison, Pia A1 - Addison, Matthew F. A1 - Haddad, C. R. A1 - Birkhofer, Klaus T1 - Weed species, not mulching, affect web‐building spiders and their prey in organic fruit orchards in South Africa T2 - Ecosphere N2 - Weed infestation affects economically relevant orchard properties, including tree performance, yield, and fruit quality negatively, and weeds are therefore often controlled by herbicide application in con- ventional farming. The addition of organic mulch below tree canopies has been proposed as an alternative reliable practice to suppress weeds and preserve soil moisture in organic farming. Mulching, however, may also affect arthropod pest and natural enemy populations, which highlights the need for simultane- ously assessing weed, natural enemy, and animal pest communities in mulch experiments. This study addresses the limited knowledge about nonchemical ground cover management strategies for the control of plant and animal pests in orchards as a major constraint for organic growers. Here, we hypothesize that decisions about ground cover management practices in organic temperate fruit orchards affect the composition of web-building spider communities and their functional role as natural enemies of pest arthropods through effects on weed and insect pest communities. We studied weed, prey, and spider communities, as well as spider diet composition, in four temperate fruit types (apricot, peach, plum, and quince) on a single farm in the Western Cape, South Africa. We established experimental plots with and without addition of dead organic mulch under fruit tree canopies. Addition of organic mulch did not signicantly affect weed cover under trees or the taxonomic composition of weed or spider communities over the eight-month study period. However, independent of mulching, the taxonomic composition of weed communities was signicantly related to the composition of potential prey and spider communities. These relationships indirectly affected the prey composition of web-building spiders. These results suggest that the identity of weed species in the study orchards had a pronounced effect on the diet composition and functional role of web-building spiders. Future research should focus on the value of individual plant species for the promotion of pest control services provided by spiders across larger spatial scales and with higher levels of replication to allow for wider generalizations. The expected results would not only be relevant for weed control but could also be considered during the development of future fower strips in orchards. Y1 - 2020 VL - 11 IS - 3 ER - TY - GEN A1 - Feng, Lanya A1 - Arvidsson, Fredrik A1 - Smith, Henrik G. A1 - Birkhofer, Klaus T1 - Fallows and permanent grasslands conserve the species composition and functional diversity of carabid beetles and linyphiid spiders in agricultural landscapes T2 - Insect Conservation & Diversity N2 - The European Union reformed the Common Agricultural Policy (CAP 2013) to include greening measures with the aim to decrease negative impacts of farming on the environment and biodiversity. The degree to which greening measures such as permanent grassland or fallows of different ages enhance biodiversity is still debated. We investigate the effect of fallows in two different age classes and permanent grassland in the surrounding landscape on the taxonomic and functional diversity of two numerically dominant groups of natural enemies in cereal fields: soil-emerging carabid beetles (Family Carabidae, Order Coleoptera) and ground-active linyphiid spiders (Family Linyphiidae, Order Araneae). The species richness, abundance and Hill–Shannon diversity of carabids and linyphiids did not differ significantly between fallows and cereal fields and was not significantly related to the proportion of permanent grassland in the surrounding landscape. The species composition of both communities differed significantly between cereal fields and fallows. The functional distinctness, as an index reflecting the similarity among species in terms of functional traits, of linyphiids was significantly higher in fallows than in cereal fields. The trait composition of carabids was significantly related to the proportion of permanent grassland depending on field type (cereal or fallow). Our results document considerable species turnover in natural enemy communities of adjacent cereal fields and fallows, and support the assumption that older fallows (>8 years) produce functionally more diverse natural enemy communities. Maintaining fallows for a long period is an important measure to promote the functional diversity in predaceous arthropod communities. Y1 - 2021 U6 - https://doi.org/10.1111/icad.12520 SN - 1752-4598 SN - 1752-458X VL - 14 IS - 6 SP - 825 EP - 836 ER - TY - GEN A1 - Arvidsson, Fredrik A1 - Montes, Melanie S. A1 - Birkhofer, Klaus T1 - Microhabitat conditions affect web-building spider communities and their prey independent of effects of short-term wildlife fencing on forest vegetation T2 - Journal of Arachnology N2 - Spiders play a key role in forest food webs, where they regulate decomposer populations and may act as predators of pests and disease vectors. Spider community composition is determined in part by vegetation structure. Therefore, the exclusion of large mammals, such as deer and wild boar, through wildlife fencing may affect the composition of spider communities and their prey in forest ecosystems. Web-building spiders and their prey were hand-collected in plots that had been fenced for three years, as well as adjacent unfenced plots in a mixed temperate forest in north-eastern Germany. Additionally, spiders in the leaf litter were sampled in fenced and unfenced subareas by sieving litter. Wildlife fencing did not significantly affect spider densities or community composition per microhabitat. However, fencing affected the cover of different microhabitats significantly as there was a higher density of larger trees and higher leaflitter cover in fenced plots while there was a higher percentage of bare ground and deadwood in unfenced plots. Spider communities and their prey composition differed significantly between microhabitats (deciduous trees, coniferous trees, dead wood, understory vegetation, leaf litter) independent of fencing. Thysanoptera prey was mainly caught by spiders on coniferous trees and in the understory vegetation. Heteroptera prey were captured most frequently in the understory vegetation while Hymenoptera (excl. Formicidae) prey were mostly caught on deciduous trees. Several spider species showed a preference between deciduous and coniferous trees in the mixed forest. Wildlife fencing alters the vegetation structure of mixed forests and has indirect effects on spider communities and their role in forest food webs due to alteration of microhabitat availability. Y1 - 2022 U6 - https://doi.org/10.1636/JoA-S-21-046 SN - 1937-2396 VL - 50 IS - 3 SP - 308 EP - 313 ER - TY - GEN A1 - Birkhofer, Klaus A1 - Bird, Tharina A1 - Alfeus, Martha A1 - Arvidsson, Fredrik A1 - Buxton, Mmabaledi A1 - Djoudi, El Aziz A1 - Fabiano, Ezequiel Chimbioputo A1 - Kasinda, Eva A1 - Machekano, Honest A1 - Mpofu, Precious A1 - Nghipunya, Esther N. A1 - Segaiso, Bame Alice A1 - Nyamukondiwa, Casper T1 - Smallholder agriculture in African dryland agroecosystems has limited impact on trophic group composition, but affects arthropod provision of ecosystem services T2 - Agriculture, Ecosystems and Environment N2 - Agricultural intensification is a major driver of biodiversity loss, but the majority of studies highlighting these threats come from industrialised agriculture in temperate countries of the global North. However, more than 30% of global food production is produced by smallholder farmers, particularly in Africa. We know very little about the impact of these farming practices on arthropod communities and associated ecosystems in dryland agroecosystems. We investigated the trophic group composition of arthropod communities (detritivorous, herbivorous, predatory & mixed feeders) and levels of associated ecosystem functions in replicated maize fields, paired adjacent natural bushveld habitats and the edge habitats between them in north-eastern Namibia and central-eastern Botswana during the dry and wet seasons. Predator activity densities differed significantly between habitats depending on the season, with higher numbers in natural habitats in the wet season but lower numbers in the dry season compared to maize fields. In general, edge habitats had higher numbers of predators than the other habitats. Predator attack rates on artificial caterpillars in both seasons and dung removal in the wet season were higher in habitats with natural vegetation (natural and edge). However, dung removal in the dry season and herbivory in the wet season were highest in the maize fields, the latter due to high level of fall armyworm infestation. Wet season multifunctionality was higher in natural habitats in Botswana, and to a lesser extent in Namibia, than in maize fields. Smallholder agriculture is not detrimental to decomposers, herbivores and mixed feeders compared to adjacent natural habitats, but may be detrimental to the provision of some ecosystem services. These results highlight the challenge of sustainably managing dryland agricultural land that is marginal for crop production, while providing smallholders with an optimal environment to benefit from the ecosystem services associated with arthropod communities. New conservation agriculture practices need to support the production of higher and more stable yields over time, while maintaining the limited impact of smallholder agriculture on biotic communities. KW - Artificial caterpillars; Biological control; Dung removal; Herbivory; Multifunctionality; Seed predation Y1 - 2024 UR - https://www.sciencedirect.com/science/article/pii/S0167880923005194 U6 - https://doi.org/10.1016/j.agee.2023.108860 SN - 0167-8809 VL - 363 ER - TY - GEN A1 - Feng, Lanya A1 - Arvidsson, Fredrik A1 - Djoudi, El Aziz A1 - Birkhofer, Klaus T1 - Terrestrial generalist predators have larger isotopic niches but rely less on aquatic prey at a natural compared to a post-mining lakeshore T2 - Food webs N2 - The flooded pits from former opencast mining (post-mining lakes) are young aquatic ecosystems often with low primary productivity due to the high acidity. The limited availability of nutrients and simplified aquatic food webs in these artificial lakes may affect the matter fluxes towards food webs in adjacent terrestrial habitats. To understand the impact of emerging prey from a post-mining lake on terrestrial food webs and associated arthropod communities, we compared the emergence and activity of arthropods as well as the isotopic niches of generalist predators and their potential prey between lakeshores of a post-mining and a natural lake. We used aquatic and terrestrial emergence tents to sample potential prey that emerged locally (Collembola and Diptera) and pitfall traps to sample terrestrial arthropod predators (Carabidae and Araneae) from lakeshores. Community and stable isotope (δ13C and δ15N) analyses were performed to compare diversity and isotopic niches of generalist arthropod predators between the natural and post-mining lakeshores. The number of emerging aquatic and terrestrial prey did not differ significantly between lakes, but the δ15N values of aquatic emerging dipterans differed between the two lakes. Predator community diversity did not differ significantly between lakeshores, but generalist predator species from the natural lakeshore generally had larger isotopic niche sizes than the same species at the post-mining lakeshore indicating a more diverse diet. Additional estimates of diet composition suggest that predators at the natural lakeshore utilized aquatic prey to a lesser degree than at the post-mining lake, but still had a more diverse diet. KW - Carabids KW - Food web KW - Post-mining lake KW - Spiders KW - Stable isotopes KW - Subsidies Y1 - 2024 U6 - https://doi.org/10.1016/j.fooweb.2024.e00368 SN - 2352-2496 VL - 41 SP - 1 EP - 9 PB - Elsevier CY - Amsterdam ER - TY - GEN A1 - Arvidsson, Fredrik A1 - Birkhofer, Klaus T1 - The value of public databases for our knowledge of national spider biodiversity compared to a long-term scientific monitoring project. T2 - Insect conservation and diversity N2 - Citizen science can be a valuable tool for monitoring changes in biodiversity, especially for less frequently studied taxonomic groups such as spiders. These collaborative projects between scientists and private citizens can provide a cost‐effective means of collecting large data sets, while also raising awareness of environmental and sustainability issues. A comparison of two public databases ( iNaturalist and the Swedish biodiversity database Artportalen ) with a national scientific study using malaise traps (Swedish Malaise Trap Project, SMTP) sheds light on their individual and combined contribution to our understanding of spider biodiversity and geographical distribution in Sweden. iNaturalist is an important global platform for mobilising public participation in biodiversity research. While widely used internationally, its coverage in Sweden is relatively limited and tends to over‐represent species that are easy to spot and often observed in densely populated areas. Artportalen includes a large body of observations contributed through citizen science. It offers wide species coverage, supported by higher expert input. Nevertheless, it exhibits sampling bias towards species that are diurnal and common in more populated areas. Projects based on large‐scale sampling schemes such as SMTP therefore make essential contributions to our understanding of the occurrence of species, especially for rare and uncommon species or species with cryptic life histories. Records are, however, limited in distribution to the pre‐defined sample locations. Given the more resource‐intensive nature of traditional scientific surveys, a combined approach that integrates citizen science data with scientific sampling offers the most robust and comprehensive means of assessing biodiversity. KW - Araneae KW - Artportalen KW - Citizen science KW - Completeness KW - iNaturalist KW - Malaise trap KW - Recognition KW - SMTP KW - Species distribution KW - Schweden Y1 - 2025 U6 - https://doi.org/10.1111/icad.70024 SN - 1752-4598 VL - 19 IS - 1 SP - 228 EP - 239 PB - Wiley ER -