| 1. |
- Dickel, Lisa, et al.
(författare)
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Characterization of habitat requirements of European fishing spiders
- 2022
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Ingår i: PeerJ. - : PEERJ INC. - 2167-8359. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Wetlands are among the most threatened habitats in the world, and so are their species, which suffer habitat loss due to climate and land use changes. Freshwater species, and especially arthropods, receive comparatively little attention in conservation plans, and the goals to stop and reverse the destruction of wetlands published 25 years ago in a manifesto by the Union of Concerned Scientists have not been reached. In this study, we investigated the occurrence and habitat requirements at two spatial scales of two species of European fishing spiders Dolomedes, which rely heavily on declining wetland habitats in Sweden and southern Norway. We collected occurrence data for Dolomedes plantarius and Dolomedes fimbriatus, using a live-determination method. We modelled the placement of nursery webs to describe fine-scale habitat requirements related to vegetation and micro-climate. Using a machine learning approach, we described the habitat features for each species and for co-occurrence sites, thus providing insight into variables relevant for the presence and detectability of Dolomedes. Nursery placement is mostly dependent on proximity to water, presence of Carex sp. (Sedges) and crossing vegetation structures, and on humidity, while detection can be affected by weather conditions. Furthermore, co-occurrence sites were more similar to D. plantarius sites than to D. fimbriatus sites, whereby surrounding forest, water type and velocity, elevation and latitude were of importance for explaining which species of Dolomedes was present. Overall, habitat requirements were narrower for D. plantarius compared to D. fimbiratus.
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| 2. |
- Hacala, Axel, et al.
(författare)
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Drivers of taxonomic, functional and phylogenetic diversities in dominant ground-dwelling arthropods of coastal heathlands
- 2021
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Ingår i: Oecologia. - : Springer Science and Business Media LLC. - 0029-8549 .- 1432-1939. ; 197, s. 511-522
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Tidskriftsartikel (refereegranskat)abstract
- Although functional and phylogenetic diversities are increasingly used in ecology for a variety of purposes, their relationship remains unclear, and this relationship likely differs among taxa, yet most recent studies focused on plants. We hypothesize that communities may be diverse in functional traits due to presence of: many phylogenetic lineages, trait divergence within lineages, many species and random functional variation among species, weak filtering of traits in favorable environments, or strong trait divergence in unfavorable environments. We tested these predictions for taxa showing higher (ants), or lower (spiders, ground beetles) degrees of competition and niche construction, both of which might decouple functional traits from phylogenetic position or from the environment. Studying > 11,000 individuals and 216 species from coastal heathlands, we estimated functional as minimum spanning trees using traits related to the morphology, feeding habits and dispersal, respectively. Relationships between functional and phylogenetic diversities were overall positive and strong. In ants, this relationship disappeared after accounting for taxonomic diversities and environments, whereas in beetles and spiders taxonomic diversity is related to functional diversity only via increasing phylogenetic diversity. Environmental constraints reduced functional diversity in ants, but affected functional diversity only indirectly via phylogenetic diversity (ground beetles) and taxonomic and then phylogenetic diversity (spiders and ground beetles). Results are consistent with phylogenetic conservatism in traits in spiders and ground beetles. In ants, in contrast, traits appear more phylogenetically neutral with any new species potentially representing a new trait state, tentatively suggesting that competition or niche construction might decouple phylogenetics from trait diversity.
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| 3. |
- Lafage, Denis, et al.
(författare)
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A new primer for metabarcoding of spider gut contents
- 2020
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Ingår i: Environmental DNA. - : Wiley-Blackwell. - 2637-4943. ; 2:2, s. 234-243
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Tidskriftsartikel (refereegranskat)abstract
- Abstract As a key predator group, spiders have received a lot of attention by food web ecologists. The difficulty involved in studying their diet has led to the use of new technologies such as metabarcoding of gut contents. The amplification of a broad range of spider prey without amplifying spiders themselves is challenging. Until now, an efficient universal primer for this purpose was not available. We developed a novel forward primer (NoSpi2) targeting the COI gene. The primer was designed not to amplify spiders of Pardosa genus while amplifying most other invertebrates. NoSpi2 was tested together with the reverse primer BR2 in silico, in vitro on single specimens of prey and spiders, on mock and malaise trap communities, and in an ecological application. In silico evaluation predicted high primer bias for Pardosa species and more generally for spiders of the oval calamistrum clade (Lycosidae and closely related species) and low bias for other invertebrates. These results were confirmed by in vitro tests. Additionally, some spider families were not amplified contrary to our expectations. We demonstrated a high efficiency for the primer pair NoSpi2/BR2 which recovered 94% of taxa in the mock community and 85% of the taxa detected by the best invertebrate primer pair known for the malaise trap community. The field experiment showed that Lycosidae (Hygrolycosa, Pardosa, Piratula, Trochosa) DNA is not amplified by NoSpi2/BR2. It demonstrated a broad range of detectable prey species (12 orders, 67 families, 117 species). The ability of NoSpi2/BR2 primer to reliably amplify prey species, without amplifying any predator DNA, makes it an ideal choice for gut content analysis for lycosid species and related species, even enabling the homogenization of entire specimens without dissection. Given that the detected prey species included other spiders and carabid beetles, this primer could be also used to study intraguild predation.
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| 4. |
- Lafage, Denis, et al.
(författare)
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Disentangling the influence of local and landscape factors on alpha and beta diversities : opposite response of plants and ground-dwelling arthropods in wet meadows
- 2015
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Ingår i: Ecological research. - : SPRINGER JAPAN KK. - 0912-3814 .- 1440-1703. ; 30:6, s. 1025-1035
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Tidskriftsartikel (refereegranskat)abstract
- A large number of studies have tried to understand the determinants of local species richness, i.e. alpha-diversity. Studies dealing with beta-diversity are considerably less numerous but their number has increased in the recent years. In this study, we assessed the relative importance of local and landscape (i.e. composition and connectivity) variables in explaining alpha- and beta-diversities (species turnover and nestedness) of three highly diverse groups, differing in mobility and dispersal: plants, spiders, and carabids. Sampling took place in 2013, using suction samplers for arthropods and phytosociological relev,s for vegetation, in 77 hay meadows distributed along 200 km of the Loire Valley (France). We found plant alpha-diversity to be driven by local factors, whereas spider and carabid alpha-diversities were mostly determined by landscape factors (by composition and connectivity, respectively). Nestedness was negligible for the three groups. Plant beta-diversity was also mainly influenced by local factors, whereas spider beta-diversity was driven by landscape factors (composition and connectivity, equally). Surprisingly, carabid beta-diversity was mainly influenced by local factors and landscape connectivity. Despite these differences, plant, spider, and carabid beta-diversities were not different, suggesting comparable dispersal abilities and/or a low connectivity at large scale, which is in accordance with the high species turnover observed here. Managing biodiversity in meadows consequently necessitates acting at local and landscape scales, the first targeting plants and the second arthropods.
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| 5. |
- Lafage, Denis, et al.
(författare)
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Local and landscape drivers of aquatic-to-terrestrial subsidies in riparian ecosystems : A worldwide meta-analysis
- 2019
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Ingår i: Ecosphere. - : John Wiley & Sons. - 2150-8925 .- 2150-8925. ; 10:4, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Cross-boundary fluxes of organisms and matter, termed “subsidies,” are now recognized to be reciprocal and of roughly equal importance for both aquatic and terrestrial systems, even if terrestrial input to aquatic ecosystems has received most attention. The magnitude of aquatic-to-terrestrial subsidies is well documented, but the drivers behind these subsidies and their utilization by terrestrial consumers are characteristically local-scale studies, limiting the inferences that can be drawn for broader geographic scales. We therefore built and analyzed a database of stable isotope data extracted from 21 studies worldwide, to identify both landscape-scale (catchment) and local-scale (100-m riparian zone) variables that may affect the diet of terrestrial predators in riparian ecosystems. Our meta-analysis revealed a greater magnitude of aquatic-to-terrestrial subsidies (>50%) than previously reported, albeit with large geographic and inter-annual variations. Moreover, we demonstrated a large effect of landscape-scale factors on aquatic-to-terrestrial subsidies, particularly anthropogenic land use and tree cover. Local human population was the only relevant factor at the local scale. We also found that studies on landscape-scale and anthropogenic land use effects on aquatic-to-terrestrial subsidies are strongly under-represented in the ecological literature, which limits the general inferences that can currently be drawn about landscape effects. We suggest that landscape-scale studies could improve our understanding of how land use and environmental change might influence future patterns of biodiversity and ecosystem function.
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| 6. |
- Lafage, Denis, et al.
(författare)
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Relative importance of management and natural flooding on spider, carabid and plant assemblages in extensively used grasslands along the Loire
- 2016
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Ingår i: Basic and Applied Ecology. - : Elsevier. - 1439-1791 .- 1618-0089. ; 17:6, s. 535-545
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Tidskriftsartikel (refereegranskat)abstract
- In Europe, agri-environment schemes (ALS) have been implemented to counteract the effects of agricultural intensification. Studies investigating the role of management improvement induced by AES are quite numerous, but rarely take into account the effect of natural perturbations such as flooding, although severe disturbances are well known to shape community structure, Here we investigated the relative importance of management improvement and flooding to explain community parameters of two dominant arthropod groups and vegetation in alluvial meadows. Sampling took place in 2013, using suction samplers for arthropods and phytosociological releves for vegetation, in 83 meadows distributed along 200 km of the Loire Valley (France). Pair-matched approach (by R-ANOVA) was used to assess overall effects of AES whereas a gradient analysis (GLM) was carried out to assess the impact of AES prescriptions (fertilisation and cutting-date) together with indirect (long-term) and direct (short-term) effects of flooding. No significant effect of AES was found on arthropod and plant assemblages, abundance/productivity or diversity (both alpha and beta), but the number of rare plant species was higher in sites under AES. Prescriptions had little impact on most response variables considered; the only significant impact being the positive effect of high-amounts of fertilisers on spider alpha- and beta-diversities, Conversely, systematic long-term effects of flooding were found on all response variables of spiders, carabids and plants, underlining the key role of this factor in alluvial meadows, Our study demonstrates that maintaining or enhancing hydrological functioning of ecosystems is even more important than regulating both the cutting-dates and the low input of fertilisers for conservation purposes in flooded, already naturally nutrient rich, meadows.
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| 7. |
- Lafage, Denis, et al.
(författare)
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Responses of ground-dwelling spider assemblages to changes in vegetation from wet oligotrophic habitats of Western France
- 2019
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Ingår i: Arthropod-Plant Interactions. - : Springer Netherlands. - 1872-8855 .- 1872-8847. ; 13:4, s. 653-662
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Tidskriftsartikel (refereegranskat)abstract
- While many arthropod species are known to depend, directly or indirectly, on certain plant species or communities, it remains unclear to what extent vegetation shapes spider assemblages. In this study, we tested whether the activity-density, composition, and diversity of ground-dwelling spiders were driven by changes in vegetation structure. Field sampling was conducted using pitfall traps in bogs, heathlands, and grasslands of Brittany (Western France) in 2013. A total of 8576 spider individuals were identified up to the species level (for a total of 141 species), as well as all plant species in more than 300 phytosociological relevés. A generalised linear model showed that spider activity-density was negatively influenced by mean vegetation height and mean Ellenberg value for moisture. Indices of diversity (ɑ, β, and functional diversities) increased with increasing vegetation height and shrub cover. Variables driving spider composition were mean vegetation height, dwarf shrub cover, and low shrub cover (results from a redundancy analysis). Spiders, some of the most abundant arthropod predators, are thus strongly influenced by vegetation structure, including ground-dwelling species. Although later successional states are usually seen as detrimental to local biodiversity in Europe, our results suggest that allowing controlled development of the shrub layer could have a positive impact on the diversity of ground-dwelling spiders.
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| 8. |
- Lafage, Denis, et al.
(författare)
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Short-term resilience of arthropod assemblages after spring flood, with focus on spiders (Arachnida Araneae) and carabids (Coleoptera: Carabidae)
- 2015
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Ingår i: Ecohydrology. - : John Wiley & Sons. - 1936-0584 .- 1936-0592. ; 8:8, s. 1584-1599
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Tidskriftsartikel (refereegranskat)abstract
- Despite the expected increase in extreme flood frequency, the manner in which terrestrial arthropods cope with regular submersion of their habitat remains poorly understood in meadows, especially in temperate floodplains. Here, we studied the recolonization dynamics of arthropods after a severe spring flood in the Loire Valley (France). We carried out analyses at the community (order or family identification level) and species scales, focusing on the assemblages of two dominant and diverse groups: carabids and spiders. Our objectives were the following: (i) to describe the temporal changes in community structure after flooding and (ii) to assess the influence of landscape configuration on recolonization patterns of species and their functional traits. Fieldwork was performed along three sampling transects, by using 75 pitfall traps, in 2012. A total of 14767 arthropods belonging to 87 families were trapped, including 5538 spiders (55 species) and 3396 carabids (66 species). Multivariate analyses discriminated assemblages from flooded and non-flooded habitats and revealed changes over time in arthropod families and species after flood withdrawal. In particular, wolf spiders (Lycosidae) were the first to recolonize, whereas other groups clearly avoided flooded sites. Our results also revealed that short distances to hedgerows, and to a lesser extent, distance to woodlands, favoured the recolonization of large and ground-running spiders. In conclusion, our study shows the short-term resilience of certain groups or stenotopic species to flooding and also the relevance of multi-taxon-based studies. The presence of hedgerows has to be considered carefully in management plans because of their role of refuge during flooding. Copyright (c) 2015 John Wiley & Sons, Ltd.
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| 9. |
- Mammola, Stefano, et al.
(författare)
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Challenges and opportunities of species distribution modelling of terrestrial arthropod predators
- 2021
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Ingår i: Diversity & distributions. - : Wiley-Blackwell Publishing Inc.. - 1366-9516 .- 1472-4642. ; 27:12, s. 2596-2614
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Tidskriftsartikel (refereegranskat)abstract
- Aim Species distribution models (SDMs) have emerged as essential tools in the equipment of many ecologists, useful to explore species distributions in space and time and answering an assortment of questions related to biogeography, climate change biology and conservation biology. Historically, most SDM research concentrated on well-known organisms, especially vertebrates. In recent years, these tools are becoming increasingly important for predicting the distribution of understudied invertebrate taxa. Here, we reviewed the literature published on main terrestrial arthropod predators (ants, ground beetles and spiders) to explore some of the challenges and opportunities of species distribution modelling in mega-diverse arthropod groups. Location Global. Methods Systematic mapping of the literature and bibliometric analysis. Results Most SDM studies of animals to date have focused either on broad samples of vertebrates or on arthropod species that are charismatic (e.g. butterflies) or economically important (e.g. vectors of disease, crop pests and pollinators). We show that the use of SDMs to map the geography of terrestrial arthropod predators is a nascent phenomenon, with a near-exponential growth in the number of studies over the past ten years and still limited collaborative networks among researchers. There is a bias in studies towards charismatic species and geographical areas that hold lower levels of diversity but greater availability of data, such as Europe and North America. Conclusions Arthropods pose particular modelling challenges that add to the ones already present for vertebrates, but they should also offer opportunities for future SDM research as data and new methods are made available. To overcome data limitations, we illustrate the potential of modern data sources and new modelling approaches. We discuss areas of research where SDMs may be combined with dispersal models and increasingly available phylogenetic and functional data to understand evolutionary changes in ranges and range-limiting traits over past and contemporary time-scales.
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| 10. |
- Marker, Jeffery, et al.
(författare)
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Forested riparian buffer environmental variables are more important than size for species functional diversity in production forests
- 2022
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Ingår i: Forest Ecology and Management. - : Elsevier. - 0378-1127 .- 1872-7042. ; 526
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Tidskriftsartikel (refereegranskat)abstract
- Retention of forested buffers around streams following forest cutting operations is a common managementtechnique used to protect aquatic resources and conserve the surrounding ecosystem services. Species richness,or α-diversity, is commonly used as an indicator of the effects of forestry management although it provides verylittle information about those effects on ecosystem processes and function. Functional diversity links speciestraits and ecosystem function incorporating species diversity, community composition, and functional guild andis more suitable to investigate the direct and indirect effects of forestry on ecosystem function. We sampledspiders and vascular plants in buffered and unbuffered stream-forest systems in southern Sweden and used atrait-based approach to assess the effects of buffer size and environmental variables on functional diversity. Weused structural equation modeling (SEM) to explore the effects of buffer size and condition on spider and vascularplant diversity. We found no effect of buffer size on the functional richness or functional redundancy for spidersor vascular plants. Buffer size had a slight effect on the α-diversity of spiders within small buffers and fullyforested sites but the effect was small. Other buffer variables including canopy closure, buffer density, bareground coverage, and soil fertility had direct effects on spider and vascular plant functional diversity. The maindriver of functional richness was α-diversity, but our SEM analysis illustrated other environmental variablesworking jointly to drive functional diversity. Using a trait-based approach, we showed that forested buffers havea minimal overall impact on spider and vascular plant functional diversity. However, it is important to maintainhigh levels of α-diversity to preserve and promote both spider and plant functional richness in production forestsand we suggest that forest management conserves and encourages high levels of α-diversity to increase overallfunctional diversity.
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