How invasive macrophytes affect macroinvertebrate assemblages and sampling efficiency: Results from a multinational survey

• DOI: 10.1016/j.limno.2022.125998
• Publication Date: 2022-07-11T15:19:21Z
• Authors: Benjamin Misteli; Alexandrine Pannard; Frédéric Labat; Lorraine Kengne F...; Nompumelelo Cathe...; Sarah Faye Harpen...; Samuel Nkopane Mo...; Gabrielle Thiebaut; Christophe Piscart
• Keywords: Sampling efficiency; 0106 biological sciences; 570; Habitat heterogeneity; Shallow lakes; 577; 15. Life on land; 01 natural sciences; 6. Clean water; 13. Climate action; Methods; 14. Life underwater; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Aquatic plants

International audience<br/>Macrophytes play an important role in the functioning and structuring of aquatic environments but rapid mass development of invasive macrophytes is causing global concerns. Macroinvertebrate richness and abundance are strongly influenced by macrophytes as macrophytes offer habitats and food resources, increase structural heterogeneity, and provide refuges. Meanwhile, the presence of macrophytes affects the efficiency of standard sampling methods for macroinvertebrates. These effects are not well studied but are leading to biased management decisions. To fill in this knowledge gap, we analysed macroinvertebrate communities from four lakes in four countries in Europe and Africa with mass development of invasive macrophytes. We compared macroinvertebrate communities in sediment samples from a plant-free part of the lake with those in sediment and sweep samples taken within macrophyte stands. We showed that taxa richness and density were higher in sediment samples beneath invasive macrophyte stands compared to plant-free habitats. Unique taxa were found in each sample type. Sampling efficiency of each sampling method varies greatly across lakes especially when replication is low. The taxonomic richness of macroinvertebrates within invasive macrophyte stands is often underestimated compared to open water sections with the same number of samples. To reach a high sampling coverage, a higher number of samples is necessary for sampling within invasive macrophytes. Our findings call for the development of a method that allows for comparable sampling within and outside of macrophyte stands. Such method will be the foundation for future research and management of aquatic systems.<br/>