A resex Baía do Iguape (BA) como prestadora de serviços ecossistêmicos no sequestro de carbono: modelagem das alterações no estoque de carbono

Abstract

Carbon is the fourth most abundant element on the planet and in natural systems it permeates all ecosystems in different ways. In mangroves, tropical ecosystems of coastal flooded regions, the rapid cycling of nutrients and high photosynthetic rates allow high sequestration and storage of atmospheric carbon. Thus, this work aimed to model and estimate the concentrations of carbon stock/sequestration in the aboveground biomass present in the mangrove ecosystem of the Reserva Extrativista Baía do Iguape in the municipality of Maragogipe/BA, Brazil. The temporal mapping of land use was carried out using images from the Landsat 5 satellites, TM sensor, and Landsat 8 OLI sensor, both with a special resolution of 30 m, the classification method used was unsupervised by the visual interpretation technique in the Arcgis software 10.8. Linked to the mapping, the NDVI, sPRI and CO2FLUX vegetation indices were also produced to detect spatio-temporal changes in the vegetation, the modeling of carbon sequestration and carbon stocks in the mangrove was performed using the inVEST software. Transition analyzes of area for land use mapping were also carried out between the years mapped and the quantitative of natural and anthropic classes. The result of the mapping indicates an increase in the classes of mangrove and dense rainforest in 240 ha and 52 ha respectively between 1986 and 2020, linked to this, the mapping indicates an increase in natural areas by 186 ha. The classes that presented the highest amount of transition in the entire analysis were the mangrove, rainforest and grassland areas, indicating that there is still conversion of natural classes. Regarding the spectral analysis of the mangroves, the NDVI suggests a fluctuation in the vegetative vigor of the mangroves, with 2005 being the year with the highest NDVI values, while in photosynthetic production, there is a low in years with large anthropic disturbances, followed by a high in 2000 and 2020. the carbon flux, the index suggests that from 2005 there was an increase in the rate of sequestration over time, except in 2000, with the peak being in 2020. In the modeling of the carbon stock, it was possible to observe the temporal and linear increase of the carbon stock, with the years 1986 and 2040 being those with the lowest and highest carbon stocks with, respectively, 0.0001034 MtCO2/ha and 0.0002945 MtCO2/ha. Regarding the valuation of the carbon stock in 2000, a stock equivalent to US$ 13,706,342.10 was evaluated, with a ton of CO2/ha worth US$ 5,170.00. The projection for 2040 is expected to have in stock the equivalent of US$ 32,323,138.92 and a ton of CO2/ha at US$ 11,188.00. The monetary value of carbon sequestration has a maximum of US$ 28,831.41 in 2000 and a maximum of US$ 261,650.18 is projected in 2040. The analyzes showed that the greater the vegetation density, the greater the amount of carbon sequestered by mangroves and those anthropic tensors and salinity can interfere in the spectral behavior of vegetation as a function of photoprotection and water stress mechanisms. Thus, it is considered that the increases in mangroves occurred far from anthropic impacts, suggesting the existence of coastal anthropobiomes in the RESEX. The carbon stock model proves to be efficient to indicate priority areas for stock conservation, in addition to demonstrating areas where there is a lower concentration of carbon