Análise da dinâmica dos fluxos de água e carbono em diferentes coberturas do solo no Nordeste Brasileiro.

Abstract

Climate conditions linked to anthropic pressure in the Brazilian Northeast (NEB), especially the Caatinga biome, with a predominance in most of the study area, make this region one of the most vulnerable in the world. The lack of effective and continuous monitoring in this region is one of the problems that aggravates this susceptibility to soil degradation. Based on this, the present study has as its main focus the more effective and continuous monitoring of energy, water, and carbon fluxes in the Caatinga biome in areas with varying degrees of degradation and seeking to understand how these flux dynamics behave due to land cover changes. For this, field sensors were installed in areas with contrasting vegetation cover in the Caatinga, which quantified these flows over a four-year period (2013 – 2016), a study discussed in Chapter II. In order to expand our study, both temporally and spatially, medium spatial resolution remote sensing techniques were used. The main data used came from the MODIS sensor, where some studies have shown better accuracy of these data for the NEB region. With this, Chapter III addresses the monitoring of water and carbon fluxes in the NEB to investigate spatial and temporal patterns in the various biomes present in the region. The field data generated in Chapter II validated the remote sensing data, making it possible to use these data for a broader analysis in Chapter III, where the magnitudes and seasonality of Evapotranspiration (ET) and Gross Primary Productivity (GPP) were compared among the four biomes present in the NEB (Amazon, Cerrado, Caatinga, and Atlantic Forest) over 21 years (2000 – 2020). From the results, it was possible to quantify the real impact of areas that suffered any disturbance. Considerable differences were observed in the use of water for carbon production and assimilation in preserved and degraded areas of the Caatinga. Areas of preserved Caatinga (dense vegetation) managed to absorb up to 2.5 times more CO2 than areas of degraded Caatinga (sparse vegetation). Studies like this one support the adoption of measures against deforestation, encouraging both the preservation of native areas and the recovery of degraded areas. In addition, it shows the importance of preserving the Caatinga biome, given its nature of being extremely susceptible to water availability compared to other biomes.