Avifaunal diversity of Cascajo Wetland: A post-remediation baseline survey

Coastal wetlands along the Peruvian coast provide important habitats for resident and migratory birds but are increasingly affected by urban expansion, pollution, and hydrological alteration. This study presents a descriptive assessment of avifaunal diversity in Cascajo Wetland (Chancay, Lima, Peru) based on two survey periods conducted in June 2012 (dry season) and February 2013 (wet season), following previously reported wetland cleaning and decontamination activities. A total of 5,226 individuals representing 38 species and 17 families were recorded. Resident species comprised approximately 67% of the assemblage, followed by continental migrants (22%), local migrants (8%), and Andean migrants (3%). Franklin’s Gull ( Leucophaeus pipixcan ), Neotropic Cormorant ( Phalacrocorax brasilianus ), and Willet ( Tringa semipalmata ) were the three most frequently observed species, collectively accounting for over 70% of total records. Observed species richness and diversity varied among surveyed sectors, with comparatively higher values recorded in sectors where emergent aquatic vegetation was visually present during the surveys. The highest species overlap among sectors was observed between A2 and B2 (Jaccard index = 0.83). These results represent descriptive patterns observed during the survey periods and should not be interpreted as evidence of causal relationships with habitat characteristics. The occurrence of both resident and migratory species indicates that Cascajo Wetland was used by multiple avian groups within the Pacific coastal flyway during the study period. This study provides a descriptive post-remediation avifaunal baseline for Cascajo Wetland that may support future ecological monitoring and comparative assessments. Given the limited temporal replication and partial spatial coverage of the surveys, additional studies incorporating repeated sampling and quantitative environmental measurements are needed to improve understanding of temporal variation and bird–habitat associations in coastal wetlands of Peru.