Biodiversity and spatiotemporal variations of benthic macroinvertebrates in the Baoying Lake, Yangzhou, Jiangsu

Abstract

Benthic macroinvertebrates serve as important indicator organisms for water environment monitoring, and the study of their community structure and biodiversity can effectively reflect the health of the water body. From 2015 to 2019, we investigated the community structure and biodiversity of benthic macroinvertebrates in the Baoying Lake, Yangzhou, Jiangsu Province. Using both morphological traits and DNA barcoding, we identified a total of 57 species. Assigned to three phyla and five classes, these species included: 23 molluscs (15 gastropods and 8 bivalves); 12 oligochaetes; and 22 arthropods (5 malacostracans and 17 insects). Gastropods constituted the most dominant group, accounting for more than 65% of density ratio during five years. The three most abundant gastropods were Bithynia fuchsiana, B. misella, and Alocinma longicornis. Surveys on the annual variation of species diversity and community structure showed mean values of the Margalef abundance index, Simpson dominance index and Pielou evenness index at 2.27 ± 0.28, 0.82 ± 0.02, and 0.78 ± 0.08, respectively. Biotic assessments of water quality based on both the Shannon-Wiener index (H’) and the biotic index (BI) suggested varying intensities of pollutants in the Baoying Lake between 2016 and 2019. This variation is likely related to anthropogenic eutrophication, notably overstocking during barrier net aquaculture.