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Calcareous grassland is one of the most species rich and diverse habitats within Europe, but has faced decline due to agricultural intensification and abandonment. In recent years, conservation organisations have altered grazing practices in an attempt to maintain floristic components. However, there has been little consideration of the effects of changes in grazing practices on invertebrates. This study determines the impacts of commonly used grazing practices in upland calcareous grasslands on spiders in relation to vegetation structural complexity.
Typical grazing management regimes were examined in three regions of upland calcareous grassland in Britain. Spiders were sampled from April to August 2014 and vegetation structural complexity was recorded in 2 × 2 m quadrats paired with pitfall traps sequentially throughout the sample period.
There were three distinct spider assemblages among the grazing regimes; ungrazed, heavy sheep grazed and one shared between cattle and light sheep (which had a comparable grazing intensity). The distinct spider assemblages among grazing regimes can be attributed to the interaction of grazing and habitat structure.
Increased vegetation structural complexity in ungrazed regimes resulted in an assemblage dominated by ‘sheet web weavers’ (dominated by Linyphiidae). In contrast, reduced vegetation structural complexity and homogeneity in heavy sheep grazing resulted in an assemblage dominated by ‘other hunters’ (including Oedothorax and Erigone genera).
Grazing regime alters vegetation structural complexity and is important in supporting distinct spider assemblages. This research indicates that low intensity conservation grazing regimes, in addition to no grazing, should be promoted across upland calcareous grassland landscapes to maintain heterogeneity.
Across Europe, calcareous grasslands become increasingly fragmented and their quality deteriorates through abandonment and land use intensification, both affecting biodiversity. Here, we investigated local and landscape effects on diversity patterns of several taxonomic groups in a landscape of highly fragmented calcareous grassland remnants. We surveyed 31 grassland fragments near Göttingen, Germany, in spring and summer 2017 for vascular plants, butterflies and birds, with sampling effort adapted to fragment area. Through regression modelling, we tested relationships between species richness and fragment size (from 314 to 51,395 m2), successional stage, habitat connectivity and the per cent cover of arable land in the landscape at several radii. We detected 283 plant species, 53 butterfly species and 70 bird species. Of these, 59 plant species, 19 butterfly species and 9 bird species were grassland specialists. Larger fragments supported twice the species richness of plants than small ones, and hosted more species of butterflies, but not of birds. Larger grassland fragments contained more grassland specialist plants, but not butterfly or bird specialists. Increasing amounts of arable land in the landscape from 20 to 90% was related to the loss of a third of species of plants, and less so, of butterflies, but not of birds. Per cent cover of arable land negatively correlated to richness of grassland specialist plants and butterflies, but positively to grassland specialist birds. We found no effect by successional stages and habitat connectivity. Our multi-taxa approach highlights the need for conservation management at the local scale, complemented by measures at the landscape scale.
1. Entomology is key to understanding terrestrial and freshwater ecosystems at a time of unprecedented anthropogenic environmental change and offers substantial untapped potential to benefit humanity in a variety of ways, from improving agricultural practices to managing vector-borne diseases and inspiring technological advances.2. We identified high priority challenges for entomology using an inclusive, open, and democratic four-stage prioritisation approach, conducted among the membership and affiliates (hereafter 'members') of the UK-based Royal Entomological Society (RES).3. A list of 710 challenges was gathered from 189 RES members. Thematic analysis was used to group suggestions, followed by an online vote to determine initial † Deceased.
Upland calcareous grassland landscapes are typically comprised of a matrix of calcareous grassland, acid grassland and limestone heath plant communities. This matrix of habitats is produced by a combination of underlying geology, climate and management. These landscapes are typically managed through grazing, with management targeted to maintain particular plant communities in the calcareous grassland habitat, whilst patches of acid grassland and limestone heath are not targeted by conservation management. The biodiversity value of acid grassland and limestone heath patches within the calcareous grassland matrix are unknown. This study provides the first assessment of their biodiversity value by examining aspects of epigeal spider diversity supported by these non-target habitat patches in comparison to calcareous grassland. Spiders were sampled in each habitat from April to August 2014 using pitfall traps across three upland regions in Great Britain. Spider species assemblages were distinct between limestone heath and both grassland types. Distinction in species assemblages are likely due to differences in vegetation structure and microclimate, e.g., humidity, degree of shade. Each habitat type supported several rare species (e.g., Jacksonella falconeri, Agyneta subtilis) revealing the contribution Communicated by David Hawksworth.
Electronic supplementary materialThe online version of this article (https://doi.org/10.1007/ s10531-017-1488-4) contains supplementary material, which is available to authorized users. to spider fauna. The distinct spider species assemblage and presence of rare species in limestone heath patches demonstrate their importance in the upland calcareous grassland matrix. This study highlights the value of monitoring biodiversity in non-target habitats within a habitat matrix alongside those that are actively targeted by management.
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