Impact of a dredging project on waterbird diversity and water and sediment quality in Ashtoum El-Gamil protected area, Egypt: a first seasonal overview

The present study seeks to assess waterbird diversity and water and sediment quality at Ashtoum El-Gamil protected area, Egypt, after a dredging project. The Lake Manzala dredging project started in 2017 and aims to improve the water quality in the lake mainly by enhancing water exchange between the lake and the sea. Waterbird diversity was assessed at 12 selected sites from July to December 2022. The seasonal assessment included richness, evenness, abundance, and Simpson, Shannon, and Margalef diversity indices. Water and sediment quality were assessed by measuring physicochemical parameters at four sites covering the protectorate sides. The results show that there is an effect on the investigated water and sediment quality parameters over the protectorate, while pH almost did not change in 2022 compared with past years. The estimated bird species richness was 50 species belonging to 21 families and 10 orders. Bird species diversity varied spatially and temporally during the study period. The waterbird assemblage maintained sizable abundance and richness, which were higher at the coasts because all inner islands of the lake had been removed. The highest value of species richness was recorded at site 2 (42 species), and site 1 showed the highest value of abundance (1846 ind.). The abundance and richness of waterbird depend on habitat factors such as water depth, physical and chemical conditions, and water body size. The study showed that there is a relationship between water quality and waterbird. These results indicate that the project has an impact on water and sediment quality and waterbirds diversity in Ashtoum El-Gamil protected area.