DOI: 10.5061/dryad.ps657
title: Data from: Habitat connectivity and local conditions shape taxonomic and functional diversity of arthropods on green roofs

description: Summary 1. Increasing development of urban environments creates high
 pressure on green spaces with potential negative impacts on biodiversity
 and ecosystem services. There is growing evidence that green roofs –
 rooftops covered with vegetation – can contribute mitigate the loss of
 urban green spaces by providing new habitats for numerous arthropod
 species. 2. Whether green roofs can contribute to enhance taxonomic and
 functional diversity and increase connectivity across urbanized areas
 remains, however, largely unknown. Furthermore, only limited information
 is available on how environmental conditions shape green roof arthropod
 communities. 3. We investigated the community composition of arthropods
 (Apidae, Curculionidae, Araneae and Carabidae) on 40 green roofs and 40
 green sites at ground level in the city of Zurich, Switzerland. We
 assessed how the site's environmental variables (such as area,
 height, vegetation, substrate and connectivity among sites) affect species
 richness and functional diversity using generalized linear models. We used
 an extension of co-inertia analysis (RLQ) and fourth-corner analysis to
 highlight the mechanism underlying community assemblages across taxonomic
 groups on green roof and ground communities. 4. Species richness was
 higher at ground-level sites, while no difference in functional diversity
 was found between green roofs and ground sites. Green roof arthropod
 diversity increased with higher connectivity and plant species richness,
 irrespective of substrate depth, height and area of green roofs. The
 species trait analysis reviewed the mechanisms related to the
 environmental predictors that shape the species assemblages of the
 different taxa at ground and roof sites. 5. Our study shows the important
 contribution of green roofs in maintaining high functional diversity of
 arthropod communities across different taxonomic groups, despite their
 lower species richness compared to ground sites. Species communities on
 green roofs revealed to be characterized by specific trait assemblages.
 The study also provides details on the environmental conditions that
 influence arthropod diversity and gives new perspectives on how the design
 of green roofs can be improved to increase their ecological value.
 Furthermore, the study highlights the importance of integrating green
 roofs in planning policies which aim to enhance urban habitat
 connectivity.
description: LocalVariablesDescription of local variables of study sites collected in the field. Column headings A-K: A: Study site number; B: ground or roof site; C: age of vegetation at site; D: height of site; E: area of study site; F: substrate depth in cm; G: type of substrate; H: proportion of bare ground; I: proportion of sedum plants; J: number of plant species; K: abundance of flowering plantsSpeciesTraitsSpecies traits collected from sources mentioned in the publication.ConnectivityVariablesFiles containing connectivity measures for different binary landscape matrix (brown, non-vertical, urbangreen, vegebrown) at 4 different scales (100, 200, 300 and 400m radius). In each file 3 connectivity measures for each site are listed. Column headings: nr_final = number of site; CWED = edge density; MPI =mean proximity; MNN = mean nearest neighbour distance.SpeciesAbundanceSpecies abundance tables for the four investigated species. First column gives the site number, the following columns gives the number of individuals of the respective species (column heading) captured at each site.