Green roofs have recently gained recognition for their potential contribution to urban ecosystems by providing, among other services, habitat for plants and animals, and stepping stones for mobile organisms, thereby enhancing permeability among habitat patches across densely built cities. In Switzerland, investigations over the past 20 years on more than one hundred distinct green roofs across six cities have provided an unprecedented dataset on ground beetles, albeit with information that is scattered across unpublished reports and local databases. We present here for the first time a synthesis of the state of knowledge of ground beetle communities from green roofs in Switzerland. We describe 91 ground beetles species (19,428 individuals) and highlight patterns of species occurrence and composition across green roofs and cities. Most of the roofs host ground beetle communities dominated by five common mobile species with quite diversified ecological requirements. In addition, we observed nine species (10% of all species collected) that are conservation concerns in Switzerland and Central Europe as well as numerous stenotopic species (from grasslands and pioneer vegetation). This indicates that, besides sustaining local populations of common species, green roofs can also offer suitable ecological conditions of high conservation interest. We suggest both improving the design of green roofs (composition and configuration of vegetation, as well as soil depth and substrate composition) to increase their ecological value for species with the most different ecological needs, and to integrate green roofs into urban planning to make them more efficient as biodiversity supports.Keywords Biodiversity . Urban ecology . Urban green . Vertical green . Endangered species . Carabid beetles . Green infrastructures . Red list species * Gaël Pétremand

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Description du sujet. Cet article traite des populations de carabes observés en vignobles. Objectifs. Les objectifs sont d’évaluer l’impact de différents modes de gestion de l’enherbement viticole sur les populations de carabes et leur potentiel en tant que prédateurs de certains ravageurs de la vigne. Méthodes. Deux vignobles, caractérisés chacun par différentes gestions de l’enherbement, situés dans le canton de Genève (Suisse), ont été échantillonnés à l’aide de 60 pièges à fosse pour différentes gestions de l’interligne. Les observations ont été effectuées de mars à octobre 2014 et une identification botanique a eu lieu en juin. Résultats. Au total, ce sont 951 carabes appartenant à 36 espèces qui ont été capturés sur les deux vignobles. Un sol nu, pauvre en espèces végétales et désherbé avec des herbicides, diminue l’abondance des carabes de moitié vis-à-vis d’un enherbement spontané. Un enherbement composé d’une flore spontanée, comparé à des engazonnements, favoriserait les populations de carabes en période de croissance de la vigne en termes de diversité et d’abondance. Conclusions. La phénologie de certaines espèces de carabes coïncide avec celle de certains ravageurs viticoles. Néanmoins, les espèces les plus fréquemment piégées ont un régime alimentaire omnivore et présenteraient un faible potentiel de prédation.

Extensive green roofs are recognised as being a suitable habitat for some specific plants and arthropods that are resistant to very extreme hot and dry conditions. Little is known about spider species visiting and living on green roofs. In 2018 and 2019, 29 green roofs in Basel and four roofs in Aarau (Switzerland) were sampled using pitfall traps during the entire growing season. In the sampling period, 18467 adult spiders were collected and identified into 123 species. Two species were collected for the first time in Switzerland: Erigone dentosa O. Pickard-Cambridge, 1894 and Runcinia grammica (C. L. Koch, 1837). According to the Red List of Germany (and especially Baden-Württemberg), 26 species are of special interest from a nature conservation perspective. On the other hand, four species are alien species (i.e. they originate from other continents), and 14 species are expanding their range northward. Green roofs may therefore harbour endangered species, but there is also the possibility that the newly invading species may become dominant. Only after many years or even decades will it be possible to judge whether green roofs are primarily substitutes for lost habitats or stepping-stones for new invaders.