Distribution patterns of aquatic birds in a high-Andean wetland in southeastern Peru: an approach based on environmental factors

Abstract

High-Andean wetlands play a crucial role in the conservation of avian biodiversity, acting as ecological oases amidst the arid Andes. However, these ecosystems face increasing anthropogenic and climatic pressures, jeopardizing both the ecosystem services they provide and the biodiversity they harbor. Moreover, research on these ecosystems remains scarce, limiting the knowledge necessary for their effective conservation. This study, conducted in Lake Piuray in the southeastern Andes of Peru, investigated the spatial and temporal distribution patterns of aquatic birds, assessing the influence of environmental variables such as depth and chlorophyll-a content. From December 2022 to November 2023, monthly surveys were carried out at 13 counting points distributed across four zones of the lake, encompassing natural and altered habitats such as lakeshore beaches and cultivated areas. Distribution maps were generated using weighted interpolation models and additive models to analyze non-linear relationships between bird abundance and environmental variables. Additionally, differences between seasons (wet and dry) and the evaluated zones were analyzed using non-parametric tests. A total of 43 aquatic bird species were recorded, with 19,768 individuals. Areas with low depth (<15 m) and intermediate to high levels of chlorophyll-a (I543 index: 0.20-0.25) concentrated the highest abundance and species richness. Zones with lakeshore beaches showed greater abundance and richness, while deeper zones exhibited the lowest values. At the family level, shorebirds preferred shallow waters, and diving birds tolerated greater depths. Although no significant differences in richness, abundance, and diversity were found between seasons at the community level, differences were identified in six families, with variations in their abundance between the wet and dry seasons. These results highlight the importance of shallow areas with high chlorophyll-a concentrations for the conservation of aquatic birds in high-Andean wetlands. This study is one of the few to analyze the influence of environmental and temporal factors on the distribution of high-Andean aquatic birds, and its representative nature makes it a valuable model for identifying priority areas for the conservation of these species.