Response of freshwater mussel recruitment to hydrological changes in a eutrophic floodplain lake

• Published in: The Science of the total environment 2020-02, Vol.703, p.135467-135467, Article 135467
• Main Authors: Ćmiel, Adam M., Strużyński, Andrzej, Wyrębek, Maciej, Lipińska, Anna M., Zając, Katarzyna, Zając, Tadeusz
• Format: Article
• Language: English
• Subjects: Animals; Ecosystem; Endangered Species; Eutrophication; Flow velocity; Hydrology; Juveniles; Lakes; Lentic conditions; Microhabitats; Reynolds number; Unionidae
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2019.135467

Although eutrophication of freshwaters is a natural process, the human impact often leads to inland waters becoming overloaded with nutrients, impoverishing many valuable and vanishing habitats, such as floodplain lakes. These changes need to be reversed if the occurrence of endangered aquatic species is to be restored. In this paper we analyse the impact of a change in the water regime of a naturally eutrophic floodplain lake, which harbours a large diversity of Unionidae (large freshwater mussels), a globally threatened taxonomic group that provides important ecosystem functions and services. We found that a slight increase in the discharge from this waterbody, following the construction of an additional outflow pipe, positively influenced recruitment in three of the five mussel species inhabiting the lake. We also found that, after the construction of this additional outflow, the niches of juveniles of Anodonta cygnea and Unio spp. changed, revealing differences in their hydrological requirements. Our results suggest that, as in lotic habitats, complex hydraulic parameters are highly significant to unionid mussels in lentic conditions. [Display omitted] •Additional outflow channel was constructed to reduce the retention time and halt the degradation of a eutrophic lake•The change in the water regime positively influenced recruitment in three of the five mussel species inhabiting the lake•The change in the water regime revealed differences in hydrological requirements between mussel species•As in lotic environments, complex hydraulic parameters are highly significant to unionid mussels in lentic environments