Green landscape and macrophyte cover influence macroinvertebrate taxonomic and functional composition in urban waterbodies at multiple spatial scales

Abstract

Urban waterbodies provide important services to humans and play a considerable role in biodiversity conservation. Yet, we still know very little about how urban pond ecosystems may respond to ongoing and future stresses operating at multiple spatial scales. Here we examined the littoral macroinvertebrates in 20 urban waterbodies as an indicator community to assess how local waterbody condition and urban land use affected their taxonomic and functional composition. Although macroinvertebrates were diverse (total richness of 60 taxa ranging from 10 to 41), they were dominated by two major taxonomic groups, the Diptera Chironomidae (36%) and the Annelida Oligochaeta (22%), which largely represented the dominant functional group of the Collectors-Gatherers (63%). Fuzzy clustering identified four different types of communities based on taxonomic and functional groups. These reflected inversed gradients in the dominance of Collectors-Gatherers versus ponds with higher abundances of Herbivores (Gastropoda Pulmonata, Hemiptera, Trichoptera), Collectors-Filterers (Gastropoda Prosobranchia, Crustacea Ostracoda), Predators (Odonata), and Parasites (Nematoda, Hydracarina). Distance-based redundancy analysis identified macrophyte cover and green landscape (parks and buildings with yards) within a 100 m radius as the best drivers of macroinvertebrate taxonomic and functional composition. We also noted a comparable variance explained by models that included parks within a 500 m radius or buildings with yards within a 2000 m radius. Our results have implications for urban landscape management as it suggests that human alteration in the urban landscape can be transmitted at least up to 2000 m from ponds.