Índice de priorização territorial para pagamento por serviços ambientais: proposta metodológica aplicada ao semiárido cearense

Abstract

Desertification is one of the main socio-environmental challenges in the semi-arid region of Ceará, intensified by the expansion of agriculture and livestock, land fragmentation, and the conversion of native vegetation, resulting in biodiversity loss, soil degradation, and a reduction in ecosystem services. This doctoral thesis aimed to develop a territorial prioritization methodology for Payment for Ecosystem Services (PES) programs, focusing on the Sertões de Irauçuba and Centro-Norte regions, recognized as critical desertification hotspots in the state of Ceará, Brazil. The methodological approach integrated geoprocessing, multicriteria analysis, and ecosystem services valuation, leading to the development of the Priority Ecological Importance Index (IEP), the Provider Priority Index (IPP), and the Territorial Prioritization Index for PES (IPT/PES). The study analyzed land use and land cover dynamics between 1986 and 2023, land tenure structure, and the status of Legal Reserves at a territorial scale. The results revealed an expressive conversion of Dense Caatinga into agricultural areas, with cultivated lands increasing by more than 1,200% during the period, alongside a significant reduction in native vegetation. Land tenure analysis indicated a predominance of minifundia and small properties, which face greater challenges regarding environmental compliance, while the assessment of Legal Reserves showed regional surpluses unevenly distributed among municipalities. The economic valuation of ecosystem services demonstrated significant losses associated with land-use conversion, reinforcing the importance of economic instruments for native vegetation conservation. The proposal of the IPT/PES, based on the integration of the IEP and IPP indices, represents a methodological contribution to the debate on territorial prioritization for PES programs, providing conceptual support for future studies and for the improvement of environmental policies in the semi-arid region of Ceará.