Effects of sand nourishment on benthic communities in sandy beaches
Sand nourishment, is common coastal protection measure along the German Baltic Sea beaches, involves large-scale sand nourishments occurring in a 5-year cycle along a 4-km stretch at the sandy coast of Ahrenshoop. The most recent replenishment took place between October 2021 and March 2022. Monitoring of the meiofauna communities at the beach-water interface was conducted at six stations, both before (in September 2021) and for a year after the event (in March and September 2022, March 2023). to evaluate the impact of sand nourishment on meiofauna communities of this touristic beach, two complementary approaches were employed: The whole community metabarcoding and the traditional method of morphological determination and counting of the animals. Both methodologies yielded consistent results concerning the communities' response to the disturbance and subsequent recovery. During the period from autumn 2021 to spring 2023, drastic changes in the composition of communities were observed., including the disappearance of the higher-level taxa Acari and Annelida, a substantial decrease in Copepoda, and a notable increase of Platyhelminthes. Recommendations for efficiently assessing the effects of disturbances in sandy-beach ecosystems are provided for future endeavors.