Showing papers by "Volkmar Wolters published in 2018"

Attractiveness of wildflower mixtures for wild bees and hoverflies depends on some key plant species

Abstract: Agricultural intensification is considered to be a major driver of terrestrial biodiversity decline. Resulting loss, isolation and degradation of flower-rich habitats are threatening pollinators. Agri-environmental schemes (AES) aim to counteract these negative effects, including measures to enhance floral resources in agricultural landscapes. The impact of plant species composition on their efficiency to mitigate pollinator loss, however, is largely unexplored. We tested four recommended seed mixtures for their attractiveness to wild bees and hoverflies in a replicated plot design over two consecutive years against the background of the seedbank. Of the 94 available plant species, 14 key plant species were crucial for the whole flower-visiting bee and hoverfly community. Approximately one third of each originated from the seedbank. The four top plants already supported 80% of flower visitors. Although seed mixtures differed significantly in attracting flower visitors at the plot level, the presence of key plants was more important than plant species diversity per se. Seed mixtures showed contrasting attractiveness for wild bees and hoverflies. Identification of plant species exclusively utilised by specific taxonomic groups opens opportunities for assorting plant mixtures for specific ecosystem functions or taxa of conservation concern. Plant species shared by common pollinators are valuable for overall pollinator diversity. The fact that rare and specialised pollinator species were mostly absent, however, substantiates that within 2 years of establishment, flowering resources are not the sole limiting factor in modern agricultural landscapes. Considering additional resources seems indispensable to maximise the conservation of species-rich pollinator communities.

GIEßEN: University Collections: Justus Liebig University Gießen

Abstract: The collection of the Department of Animal Ecology and Systematics at the Justus Liebig University Giesen comprises a broad range of invertebrates and vertebrates, skulls, eggs, bird nests, and genetic resources. In total, more than half a million specimens of organismic samples and more than 20,000 specimens of genetic samples are stocked. The collection is complemented by anatomic maps and models. As the Justus Liebig University strongly emphasizes organismic aspects of academic training in biology, a large part of the collection is regularly used for teaching Germany’s native fauna. For example, approximately 5000 invertebrates out of 90 taxa are used for mandatory courses on taxonomic identification. The collection also contains voucher specimens of scientific studies and research projects of the past decades. A collection’s highlight is the material sampled for the faunistic inventory of the Hoher Vogelsberg area in Hesse, which is part of the largest volcanic region in Europe. Another highlight is one of the largest DNA reference collections for worldwide freshwater mollusks. It is on of the most complete wet collections of macrozoobenthic taxa of worldwide ancient lakes, i.e. extant lakes orders of magnitudes older than most lakes on earth. This part of the collection is also a valuable DNA reference collection for some poorly studied regions such as the Tibetan Plateau.

Prey-dependent benefits of sown wildflower strips on solitary wasps in agroecosystems.

Abstract: Sown wildflower strips can support insects that collect pollen for their larvae. How these strips affect flower visitors with carnivorous larvae, however, is almost unknown. We studied the impact of wildflower strips and their surroundings on two common solitary wasps: the caterpillar‐hunting Ancistrocerus nigricornis Curtis and the spider‐hunting Trypoxylon figulus Linnaeus. Trap‐nest locations at 22 semi‐natural habitats in central Germany formed independent gradients in landscape complexity and distance to either one or several wildflower strips in their surroundings. For each brood cell, we recorded the number of prey items, total caterpillar weight and spider species richness. Ancistrocerus nigricornis built more cells in proximity to wildflower strips and with increasing amount of surrounding grassland. Fewer prey items provided in landscapes with large shares of semi‐natural habitats suggest that in these landscapes high‐quality prey is available. In contrast, T. figulus built more cells with increasing distance of nests to wildflower strips. If there were few strips, T. figulus built more cells in grassland‐rich landscapes, whereas low shares of grassland were compensated when several wildflower strips were present. Benefits of flowering strips for T. figulus seem related to flower resources for adults, rather than through prey provisioning. In conclusion, wildflower strips promote prey‐hunting wasps through species‐specific effects on adult and larval food provisioning. Considering the differential effects of wasps on crop pests (caterpillars) and natural enemies (spiders), the functional role of wildflower strips in agroecosystems may be much greater than assumed when solely focusing on pollination.

Agri‐environmental schemes affect the trophic niche size and diet of common carabid species in agricultural landscapes

Abstract: 1. Carabids are abundant in agroecosystems and provide biocontrol services by feeding on weed seeds and pests. We compare the effects of two fundamentally different agri‐environmental schemes (AES) on the numeric and trophic responses of four common carabid species: Anchomenus dorsalis, Poecilus cupreus, Pseudoophonus rufipes and Pterostichus melanarius.

How the sustainable intensification of agriculture can contribute to the Sustainable Development Goals

Abstract: Arbeitspapier 2018 How the sustainable intensification of agriculture can contribute to the Sustainable Development Goals The need for specific socio-ecological solutions at all spatial levels R. Delzeit,1 I. Lewandowski,2 A. Arslan,3 G. Cadisch,4 J. W. Erisman,5 F. Ewert,6 A. M. Klein,7 C. von Haaren,8 H. Lotze-Campen,9 W. Mauser,10 T. Plieninger,11 A. Ratjen,12 V. Tekken,13 V. Wolters,14 N. Brüggemann15,*