Seasonal precipitation and anthropogenic pressure affect the water quality of reservoirs in the highland humid forest enclaves

Abstract Aim Humid forest enclaves are areas with privileged rainfall patterns compared to the surrounding regions, which favours their use for human settlement and agricultural activities, actions that promote severe transformations of the landscape and can contribute to the degradation of local water resources. From this perspective, given the great importance of water reservoirs for this region and the high demand for water, this study aimed to analyse the conservation status of water quality in reservoirs subjected to different anthropic disturbance in a humid forest enclave in the State of Paraíba, Brazil. Methods Sampling campaigns were carried out for one year in six reservoirs: Mazagão I, Mazagão II, Vaca Brava, Saulo Maia, Rio do Canto and Lagoa do Paó, to measure the physic-chemical variables of the water. Results The influence of annual rainfall patterns on the capacity of these ecosystems to respond to anthropic pressures, indicating the effects of seasonality in the Lagoa do Paó reservoir. For the Vaca Brava, the low accumulated water volumes turned out to be more critical for changes in water quality than the use and occupation of the margins of this reservoir. Furthermore, the Mazagão I and II reservoirs showed low electrical conductivity. The Saulo Maia reservoir exhibit clear waters with low phosphorus content and can be used as a reference for a preserved environment for a highland humid forest enclave. Conclusions The conservation of the reservoir environment in the highland humid forest enclave is not sufficient to guarantee the water quality, as it is concentrated an affected at a certain time of the year. These aquatic ecosystems are under great pressure and the lack of decisions based on technical criteria makes them vulnerable to eutrophication. Resumo Objetivo Os Brejos de Altitude são áreas com regime pluviométrico privilegiado em relação ao seu entorno, o que favorece seu uso para ocupação humana e atividades agrícolas, ações que promovem severas transformações na paisagem e podem contribuir para a degradação dos recursos hídricos locais. Nessa perspectiva, dada a grande importância dos reservatórios de água para essa região e a alta demanda hídrica, este estudo teve como objetivo analisar o estado de conservação da qualidade da água em reservatórios submetidos a diferentes níveis de perturbação antrópica no Brejo de Altitude do Estado da Paraíba, Brasil. Métodos Campanhas de amostragem foram realizadas durante um ano em seis res