Leaf breakdown rates as a functional indicator were influenced by an invasive non-native invertebrate in urban ponds

• Published in: Ecological indicators 2021-05, Vol.124, p.107360, Article 107360
• Main Authors: Thornhill, Ian, Friberg, Nikolai, Batty, Lesley, Thamia, Victoria, Ledger, Mark E.
• Format: Article
• Language: English
• Subjects: Biodiversity and ecosystem functioning (BEF); Ecosystem functioning; Freshwater; Functional indicators; Functional replacement; Shredders
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2021.107360

•Leaf litter breakdown in 26 ponds along a gradient of urbanisation.•Native A. aquaticus and non-native C. pseudogracilis were dominant shredder species.•Native shredder diversity decreased significantly across urbanization gradient.•C. pseudogracilis maintained breakdown rates in the most disturbed ponds.•Use of ecosystem functioning indicators should be paired with structural measures. Impacts on biodiversity and the functioning of ecosystems are often overlooked in small waterbodies as they are not regularly monitored as part of the Water Framework Directive (WFD). These small systems are, however, often essential for freshwater biodiversity and are frequently characterized by high beta-diversity. In this study we examined shredder diversity and ecosystem functioning (leaf litter breakdown) as indicators of environmental stress along a gradient of urbanisation. The native isopod Asellus aquaticus and the non-native shrimp Crangonyx pseudogracilis (Amphipoda) were dominant species of the shredder communities in 26 study ponds. Variation in shredder community composition among ponds was explained by pond surface area (P