Contribution of green roofs to urban arthropod biodiversity in a Mediterranean climate: A case study in València, Spain

Studies on biodiversity on green roofs have been carried out in parallel to the degree to which these infrastructures have been implemented in different countries. There are no studies about biodiversity of fauna in these habitats in Spain and other countries of Mediterranean Europe, except France. This study compares the arthropod community of a green roof to that of a conventional flat roof with gravel covering and two ground-level gardens, in a geographical area where the territory is a matrix of urban and agricultural lands. The interest of the results is twofold: no such work is available in this Mediterranean region, and the stressful environmental conditions. No significant differences appeared for relative abundance, taxa richness, Shannon Index, and effective number of taxa between the studied habitats. However in taxa composition and abundance terms, the arthropod community on green roofs differed significantly from that of ground-level gardens, and exclusive species were captured in both habitats. The relative abundance of the different functional groups captured showed different seasonal patterns in ground level gardens and green roof. Our results also confirm that green roofs significantly increase biodiversity compared to conventional roofs. Thus, in the climate conditions of Mediterranean region, our study suggests that green roofs may also be suitable solutions to increase and improve the arthropods biodiversity in urban areas.