Dinâmica espacial da cobertura florestal e dos estoques de carbono em cenários futuros no Brejo paraibano (estado da Paraíba – Brasil) (2023–2100)

Abstract

The Atlantic Forest supports high biodiversity and provides essential ecosystem services. However, the history of land use and occupation in this biome has resulted in a landscape marked by native vegetation loss and fragmentation. In northeastern Brazil, this biome also occurs in the Brejos de Altitude, where Seasonal Semideciduous Forest predominates and agricultural and livestock pressure contributes to vegetation loss and changes in the carbon balance. In Paraíba, the Brejo Paraibano stands out for its marked reduction in forest cover, with implications for landscape fragmentation and for ecosystem services associated with carbon storage and sequestration. This study analyzed the future spatial dynamics of native forest cover in the Brejo Paraibano, as well as changes in carbon stocks and fluxes and their economic valuation, from 2023 to 2100, based on three simulated scenarios: Business-as-Usual Scenario (CT), Conservationist Scenario I (CC I), and Conservationist Scenario II (CC II). The approach integrated the environmental delimitation of the study area, land use and land cover change simulation, the assessment of forest loss and fragmentation, and the economic valuation of CO₂ fluxes. The spatial extent was delimited through the integration of spectral indices derived from Sentinel-2 images acquired during the dry season and the application of a threshold to identify the municipalities linked to the study area. Land use and land cover scenarios for 2030–2100 were then simulated in Dinamica EGO under different deforestation rates. Landscape metrics were calculated in Fragstats to evaluate native forest loss and fragmentation across the simulated scenarios. Finally, carbon stocks and decadal fluxes were estimated with InVEST, and an economic valuation was performed. The results indicated that the environmental delimitation totals 1,484.04 km² and encompasses 16 municipalities associated with the environmental system. During the historical period from 2013 to 2023, forest area declined from 52,302.39 ha to 35,232.46 ha, while carbon stocks decreased from 25.01 to 16.85 MtCO₂, resulting in a net emission of 8.16 MtCO₂, equivalent to US$ 1.665 billion. In future projections for 2023–2100, the Business-as-Usual Scenario indicates the continuation of losses, with forest area declining to 13,697.46 ha and carbon stocks declining to 6.55 MtCO₂ by 2100, as well as a cumulative nominal loss of approximately US$ 3.2 billion for the period 2030–2100. In contrast, conservation scenarios project gains in forest cover and carbon stocks. In CC I, by 2100, forest area reaches 41,032.62 ha, with carbon stocks of 19.62 MtCO₂, and the cumulative nominal economic gain amounts to US$ 0.92 billion. In CC II, by 2100, forest area reaches 104,077.50 ha, with carbon stocks of 49.77 MtCO₂, and the cumulative nominal economic gain reaches US$ 11.17 billion. Business-as-usual land-use trajectories intensify vegetation loss and the reduction of carbon stocks, whereas conservation trajectories alter fragmentation patterns and favor the carbon balance over the coming decades, providing a basis for discussing conservation and restoration priorities and supporting territorial planning decisions.