The importance of blue and green landscape connectivity for biodiversity in urban ponds

Abstract

The negative impact of urbanization on biodiversity can be buffered by blue (e.g., rivers, ponds) and green (e.g., parks, forests) spaces. However, to prevent biodiversity loss and reduce the risk of local extinctions, blue and green spaces need to be connected by corridors, so that organisms may disperse between sites. Landscape connectivity affects local community composition and metacommunity dynamics by facilitating dispersal. The goal of this study was to test the relative roles of pond environmental properties, spatial structure, and functional landscape connectivity on differentiation of invertebrate metacommunities in urban ponds in the city of Stockholm, Sweden. We characterized functional connectivity as blue connectivity (distance to water bodies), green connectivity (land use), and combined blue-green connectivity. We estimated functional connectivity by using electrical circuit theory to identify dispersal corridors. Interestingly, while circuit theory is often used in single-taxon studies, this method has rarely been applied to multiple taxa forming a metacommunity, as we have done in this study. Indeed, our study contributes toward an increased focus on the role of dispersal at the metacommunity level. We deter-mined that functional connectivity was the most important factor in explaining community differentiation, with the local environment contributing comparatively little, and spatial structure the least. Combined blue-green functional connectivity had a major influence on structuring urban pond communities, explaining 7.8% of the variance in community composition across ponds. Furthermore, we found that increased functional connectivity was associated with an increase in the number of species. In summary, our results suggest that to preserve biodiversity in urban ponds, it is important to enhance functional connectivity, and that open green spaces could augment blue corridors in maintaining functional connectivity in urban pond metacommunities. To generalize these findings, future urban biodiversity studies should compare how functional connectivity affects meta-communities across multiple major cities. (C) 2021 The Author(s). Published by Elsevier GmbH on behalf of Gesellschaft fur Okologie.

Keywords

Aquatic fauna; Circuit theory; Dispersal corridors; Invertebrates; Landscape resistance; Metacommunity dynamics

Published in

Basic and Applied Ecology
2021, volume: 57, pages: 129-145
Publisher: ELSEVIER GMBH

SLU Authors

• Bjelke, Ulf

  • SLU Swedish Species Information Centre, Swedish University of Agricultural Sciences
    

Global goals (SDG)

SDG11 Sustainable cities and communities
SDG15 Life on land

UKÄ Subject classification

Ecology

Publication identifier

• DOI: https://doi.org/10.1016/j.baae.2021.10.004

Permanent link to this page (URI)

https://res.slu.se/id/publ/114926