Bird diversity and health status of bioindicator species (Coturnix coturnix, Horsfield, 1821) in Egypt’s Manzala Lagoon: Seasonal Resilience Monitoring

Manzala Lagoon, the largest coastal wetland of Egypt, lies within the Nile Delta and serves as an essential sanctuary for both resident and migratory birds. Despite its importance for regional biodiversity, the ecosystem faces significant anthropogenic pressures, with recent dredging activities constituting a major disturbance. This study aimed to evaluate dredging impacts on bird diversity and environmental health in the Ashtoum El-Gamil Protected Area. Seasonal monitoring in 2024, combining camera-based morphological identification with molecular barcoding of feathers (n=13; cytochrome oxidase 1 gene), documented 123 species across 11 orders and 23 families, with 51 species consistently observed year-round. Health assessments in the endemic Coturnix coturnix (Common Quail), were conducted by measuring genotoxic damage, DNA repair capacity (via poly(ADP)-ribosylation), and total antioxidant capacity (TAC) in gut, liver, and gonads. Results revealed reduced DNA recovery, elevated antioxidant capacity, and a prominent 40 kDa PARP immunoreactive band, particularly in gut and gonads. These oxidative stress indicators were independent of low heavy metal loads, implicating factors like rising temperatures may be the primary drivers. These findings highlight dredging's limited immediate effects on species diversity but underscore subtle health risks, advocating sustained, long-term monitoring and targeted management to safeguard wetland biodiversity.