Contribution of ruderal herbaceous vegetation to supporting services in mediterranean urban greenspaces

Abstract

In the current global context of increasing urbanization, urban greenspaces are expected to play a key role in supporting ecosystem services. Spontaneous ruderal vegetation has an important function in urban greenspaces, but more in-depth studies are needed to increase our knowledge of its contribution to providing supporting ecosystem services. We aimed to uncover the contribution to biodiversity maintenance, primary production and nutrient cycling of four selected plant communities that are widely distributed in Mediterranean urban greenspaces, namely the perennial herb communities of Malva spp., roadside vegetation with Diplotaxis virgata, annual grasslands of Hordeum murinum subsp. leporinum and perennial grasslands of Dactylis glomerata. We determined the floristic composition, species richness, species density, abundance, alpha diversity (Shannon index, Simpson index), beta diversity (Sørensen coefficient), total vegetation cover, cover of life forms and cover of functional groups. The macronutrient content of leaves and roots of the species with the highest coverage in each vegetation type was analysed. We used the generalized linear model to relate vegetation type to compositional and structural features supporting ecosystem services. Our results showed that Mediterranean urban greenspaces have a high plant biodiversity. Roadside vegetation had the highest species richness and alpha diversity, with a high cover of S-accumulator plants (Diplotaxis virgata) showing a high N content in their leaves. Annual grasslands had the highest abundance and cover of silica-accumulator plants. The greatest floristic similarity was found between roadside communities and annual grasslands. Primary production was high in perennial herbs of Malva species, which are rich in mucilage and leaf N content. Dactylis glomerata, the dominant species in perennial grasslands, showed a higher C content in leaves, so this vegetation type can be expected to make a higher contribution to C cycling. We conclude that ruderal vegetation provides a range of supporting ecosystem services according to the community type, a finding that should be considered in the conservation and management of Mediterranean urban greenspaces.