2026-10-212026-10-212026-02-26GOMES, Dênis José Cardoso. Serviços ecossistêmicos na bacia hidrográfica do Rio Caeté: dinâmica hidroclimática, oferta e valoração sob cenários de mudança de uso e cobertura do solo. Orientador: Ely Santos Beltrão. 2026. 199 f. Tese (Doutorado em Ciências Ambientais) - Centro de Ciências Naturais e Tecnologia, Universidade do Estado do Pará, Belém, 2026.https://portaldaposgraduacao.uepa.br/handle/riuepa/373AbertoMudanças climáticasDesmatamentoImpacto ambientalProteção ambientalClimate changeDeforestationEnvironmental impactEnvironmental protectionTeseCiências Agrárias::Recursos Florestais e Engenharia Florestal::Conservação da Natureza::Conservação de Bacias HidrográficasCiências Agrárias::Recursos Florestais e Engenharia Florestal::Conservação da Natureza::Recuperação de Áreas DegradadasEnvironmental changes, mainly represented by natural and anthropogenic factors—such as climatic extremes and the advance of deforestation—exert pressures that cause imbalances in the functioning patterns of environmental systems, including Ecosystem Services (ESs). Analyzing changes in ESs within this context of intense environmental transformations at the watershed scale allows for assessing the extent to which ESs related to the hydrological cycle, such as water provision and regulation (gas, climate, water, extreme events, and erosion control), are being affected. The objective of this research was to analyze the extent to which environmental changes have impacted the provision of ESs in the Caeté River Basin (CRB). In the climatic analysis, hydroclimatic data were used, including climate indices, precipitation, maximum air temperature, evapotranspiration, and streamflow. The Mann–Kendall and Pettitt tests were applied to detect the presence and timing of climatic change signals. To assess the ESs, geospatial data (altitude, slope, geomorphology, hydrography, roads, and land use and land cover) were obtained to project deforestation and the provision of ESs in the CRB for the year 2040. Environmental modeling using Dinamica EGO was employed to perform the projection, and the methodology proposed by The Economics of Ecosystems and Biodiversity (TEEB) was applied to classify the ESs based on land use and land cover (1985, 2023, and 2040). The Ecosystem Services Valuation (ESV) was estimated using the benefit transfer method. Statistical analyses were performed in RStudio, and the mapping was produced using QGIS 3.3 software. The northern sector of the Tropical Atlantic Ocean shows the strongest relationship with the rainfall regime in the CRB. Among the hydrometeorological variables, there is a strong correlation between precipitation and maximum air temperature, as well as between precipitation and the Caeté River streamflow. No statistically significant trends were detected for the hydrometeorological variables. However, change points were identified in the patterns of climatic indices in the years 1996 (TNA) and 2014 (TSA). The highest precipitation (2,618.5 mm) and evapotranspiration (1,628.8 mm) values are concentrated in the southwestern region of the CRB. In the northeastern region, the highest values of maximum air temperature prevail. The CRB showed extensive areas of deforestation, mainly driven by the expansion of pasturelands, which by 2023 occupied approximately 48.3% of the basin area. Oil palm cultivation has expanded in the headwater region of the Caeté River, a highly sensitive zone, and its negative effects on local hydrology are alarming. Urbanization has advanced over the lower course of the Caeté River and has also contributed, to a lesser extent, to the suppression of riparian vegetation. All these anthropogenic activities have caused substantial deficits in the ESV of the CRB, with estimated losses of approximately USD 2 billion. Livestock farming was the primary driver, leading to reductions in regulating ecosystem services (gases, climate, water, extreme events, and erosion control). Agriculture threatens the ESV associated with water provision and regulation (hydrological regulation, protection against extreme events, and erosion control). Projections for the year 2040 are entirely pessimistic. Deforestation was identified as the main cause of the reduction in ESV in the CRB. Containment measures, such as the implementation of agroforestry systems, are urgently needed to provide short-term responses.