Effects of herbaceous marsh mowing on aerial invertebrate communities:A case study in Yangtze Estuary, China

Herbaceous marshes provide vital ecological and economic benefits and are frequently managed through plant mowing. Although aerial invertebrates play key functional roles in these ecosystems, the effects of mowing on both plant-external and plant-internal invertebrate communities remain poorly understood. This study examined these effects in Chongming Island's herbaceous marshes during the 2021 growing season by comparing mown and unmown sites. Plant-external invertebrates were sampled using sweep netting, while plant-internal invertebrates were collected through plant dissection. Comparative analysis revealed that mowing significantly reduced the total density of plant-external invertebrates, with particularly significant declines in parasitoids and decomposers (P < 0.05). For plant-internal invertebrates, mowing decreased the total density and species richness, including herbivore groups (P < 0.05). Mowing directly reduced invertebrate diversity by eliminating critical aboveground habitats and indirectly restructured communities by disrupting food resources-specifically through reductions in the density of dead reeds and total nitrogen content of living reeds. These results have implicated that mosaic mowing should be adopted as a sustainable practice to enhance invertebrate biodiversity, and stubble height should be maintained below 30 cm to reduce negative impacts on plant-internal invertebrate populations.