Refine my results

Document type

Institution

Specific Collection

Language

Université de Fribourg

Impact of flower-dwelling crab spiders on plant-pollinator mutualisms

Brechbühl, Rolf ; Kropf, Christian ; Bacher, Sven

In: Basic and Applied Ecology, 2009///10.1016/j.baae.2009.07.001

Indirect effects in interactions occur when a species influences a third species by modifying the behaviour of a second one. It has been suggested that indirect effects of crab spiders (Thomisidae) on pollinator behaviour can cascade down the food web and negatively affect plant fitness. However, it is poorly understood how different pollinator groups react to crab spiders and, thus, when a...

Université de Fribourg

Ineffective crypsis in a crab spider: a prey community perspective

Brechbühl, Rolf ; Casas, Jérôme ; Bacher, Sven

In: Proceedings of the Royal Society B: Biological Sciences, 2009///doi: 10.1098/rspb.2009.1632

Cryptic coloration is assumed to be beneficial to predators because of an increased encounter rate with unwary prey. This hypothesis is, however, very rarely, if ever, studied in the field. The aim of this study was to quantify the encounter rate and capture success of an ambush predator, in the field, as a function of its level of colour-matching with the background. We used the crab spider...

Université de Fribourg

Determinants of local ant (Hymenoptera: Formicidae) species richness and activity density across Europe

Kumschick, Sabrina ; Schmidt-Entling, Martin H. ; Bacher, Sven ; Hickler, Thomas ; Espadaler, Xavier ; Nentwig, Wolfgang

In: Ecological Entomology, 2009, vol. 34, no. 6, p. 748 - 754

1. Species richness is influenced by local habitat features and large-scale climatic gradients. Usually, both influences are studied in isolation because of the divergent spatial scales at which they occur. Here, we compared the influence of large-scale climate and local habitat type on European ants using a continent-wide, standardised sampling programme.2. We investigated species richness and...

Université de Fribourg

Body size–climate relationships of European spiders

Entling, Wiebke ; Schmidt-Entling, Martin H. ; Bacher, Sven ; Brandl, Roland ; Nentwig, Wolfgang

In: Journal of Biogeography, 2009///doi: 10.1111/j.1365-2699.2009.02216.x

Aim: Geographic body size patterns of mammals and birds can be partly understood under the framework of Bergmann's rule. Climatic influences on body size of invertebrates, however, appear highly variable and lack a comparable, generally applicable theoretical framework. We derived predictions for body size–climate relationships for spiders from the literature and tested them using three...

Université de Fribourg

Alien species in a warmer world: risks and opportunities

Walther, Gian-Reto ; Roques, Alain ; Hulme, Philip E. ; Sykes, Martin T. ; Pyšek, Petr ; Kühn, Ingolf ; Zobel, Martin ; Bacher, Sven ; Botta-Dukát, Zoltán ; Bugmann, Harald ; Czúcz, Bálint ; Dauber, Jens ; Hickler, Thomas ; Jarošík, Vojtěch ; Kenis, Marc ; Klotz, Stefan ; Minchin, Dan ; Moora, Mari ; Nentwig, Wolfgang ; Ott, Jürgen ; Panov, Vadim E. ; Reineking, Björn ; Robinet, Christelle ; Semenchenko, Vitaliy ; Solarz, Wojciech ; Thuiller, Wilfried ; Vilà, Montserrat ; Vohland, Katrin ; Settele, Josef

In: Trends in Ecology & Evolution, 2009, vol. 24, no. 12, p. 686-693

Climate change and biological invasions are key processes affecting global biodiversity, yet their effects have usually been considered separately. Here, we emphasise that global warming has enabled alien species to expand into regions in which they previously could not survive and reproduce. Based on a review of climate-mediated biological invasions of plants, invertebrates, fishes and birds, we...

Université de Fribourg

A generic impact-scoring system applied to alien mammals in Europe

Nentwig, Wolfgang ; Kühnel, Elfi ; Bacher, Sven

In: Conservation Biology, 2009///doi: 10.1111/j.1523-1739.2009.01289.x

We present a generic scoring system that compares the impact of alien species among members of large taxonomic groups. This scoring can be used to identify the most harmful alien species so that conservation measures to ameliorate their negative effects can be prioritized. For all alien mammals in Europe, we assessed impact reports as completely as possible. Impact was classified as either...

Université de Fribourg

PRATIQUE: a research project to enhance pest risk analysis techniques in the European Union

Baker, R. H. A. ; Battisti, A. ; Bremmer, J. ; Kenis, M. ; Mumford, J. ; Petter, F. ; Schrader, G. ; Bacher, Sven ; Barro, P. De ; Hulme, P. E. ; Karadjova, O. ; Lansink, A. O. ; Pruvost, O. ; Pyšek, P. ; Roques, A. ; Baranchikov, Y. ; Sun, J.-H.

In: EPPO Bulletin, 2009, vol. 39, no. 1, p. 87 - 93

PRATIQUE is an EC-funded 7th Framework research project designed to address the major challenges for pest risk analysis (PRA) in Europe. It has three principal objectives: (a) to assemble the datasets required to construct PRAs valid for the whole of the EU, (b) to conduct multi-disciplinary research that enhances the techniques used in PRA and (c) to provide a decision support scheme for PRA...

Université de Fribourg

Differential effects of flower feeding in an insect host–parasitoid system

Kehrli, Patrik ; Bacher, Sven

In: Basic and Applied Ecology, 2008, vol. 9, no. 6, p. 709-717

In many insect host–parasitoid systems, both the host and its parasitoids forage on shared floral resources. As a result of insect behaviour, morphology and physiology, flower species may act selectively at different levels of such systems, e.g., between the trophic levels of hosts and parasitoids, between species within a guild, between sexes or individuals within a species or between life...

Université de Fribourg

Establishing systemic rust infections in Cirsium arvense in the field

Wandeler, Heiri ; Nentwig, Wolfgang ; Bacher, Sven

In: Biocontrol Science and Technology, 2008, vol. 18, no. 2, p. 209-214

An existing method to induce systemic rust infections in creeping thistles (Cirsium arvense) using an insect vector, the weevil Ceratapion onopordi, was successfully applied in the field. Urediniospores of Puccinia punctiformis were experimentally transmitted to naturally grown thistles, to our knowledge for the first time resulting in systemically infected shoots in an established thistle...

Université de Fribourg

Functional responses: a question of alternative prey and predator density

Tschanz, Britta ; Bersier, Louis-Félix ; Bacher, Sven

In: Ecology, 2007, vol. 88, no. 5, p. 1300–1308

Throughout the study of ecology, there has been a growing realization that indirect effects among species cause complexity in food webs. Understanding and predicting the behavior of ecosystems consequently depends on our ability to identify indirect effects and their mechanisms. The present study experimentally investigates indirect interactions arising between two prey species that share a...