Hidrossistemas urbanos e provisão de serviços ecossistêmicos: avaliação em parques municipais de Belo Horizonte

Abstract

The increasing degradation of urban hydrosystems, driven by accelerated urbanization, soil sealing, and stream channelization, has compromised the provision of essential ecosystem services (ES), such as climate regulation, carbon sequestration, and water purification. In Brazil—a country marked by intense environmental pressures and limited functional recognition of urban rivers—there is a pressing need for research that considers watercourses not merely as drainage features, but as environmental systems capable of delivering multiple ecological benefits. In Belo Horizonte, a city historically marked by the suppression of its water bodies but also a pioneer in river rehabilitation initiatives such as the DRENURBS program, there remains a lack of integrated evaluations regarding the ecological effectiveness of such interventions. This thesis aimed to investigate the capacity of urban hydrosystems located in nine riparian parks of Belo Horizonte to provide ecosystem services. These systems were categorized into three distinct types of environmental protection: reference, moderate, and rehabilitated. Hydrosystems were defined as interconnected units composed of streams, springs, and wetlands. The research adopted a multidimensional approach by applying nine ecological parameters inspired by the Urban Stream Assessment System (UsAs), adapted to the Brazilian context. These parameters included flood mitigation, aquifer recharge, carbon sequestration, water quality, and primary productivity. The methodology involved field campaigns across the 2023 hydrological year for urban rivers, and a second campaign in May 2024 for the remaining systems. Environmental protocols (PAR, PAAN, IQA) were applied, alongside laboratory analyses of physical-chemical water parameters, coliforms, organic matter, chlorophyll-a, and organic carbon in both water and soil. The data underwent rigorous statistical treatment through Analysis of Variance (ANOVA) to identify significant differences between hydrosystems and park categories. After processing, the data were normalized and categorized to apply the UsAs protocol, which expresses, in percentage, the ES provision capacity of each hydrosystem. The results showed that reference hydrosystems had the highest ES provision, as expected. However, rehabilitated hydrosystems exhibited statistically similar performance to moderate ones, confirming the thesis hypothesis and attesting to the partial effectiveness of the DRENURBS program in restoring urban river functionality. Additionally, the study confirmed that regulatory and provisioning services contribute equally to the overall ES profile, with no dominant category. Key environmental factors limiting rehabilitated systems from reaching reference-level conditions were identified, particularly water quality and hydrological dynamics. Specific attributes of springs and wetlands within the studied parks were also highlighted. Ultimately, this research advances the field of urban ecology by validating a replicable ES assessment protocol for other metropolises in the Global South and by reaffirming the strategic role of urban parks and ecological river rehabilitations in supporting environmental management and planning.