Environmental monitoring of soil carbon and ecosystem productivity across land use systems in the Atlantic Forest of Brazil.

Tropical ecosystems play a fundamental role in the global carbon cycle due to their high productivity and capacity to store carbon in vegetation and soils. However, land use change has substantially altered these processes, particularly in highly fragmented regions such as the Central Atlantic Forest Corridor (CAFC), one of the major biodiversity hotspots in Brazil. This study analyzes the relationship between gross primary productivity (GPP), soil organic carbon (SOC), land use, and soil texture to identify spatial patterns and functional regimes across the landscape. GPP data derived from MODIS, SOC stocks from MapBiomas Soil, and land use and land cover data were integrated using geoprocessing and statistical analyses. Significant differences were observed among land use classes, with higher GPP in forest ecosystems and higher SOC stocks in natural nonforest formations. The relationship between GPP and SOC was predominantly weak, indicating a decoupling between contemporary productivity and soil carbon storage. Both variables exhibited significant spatial autocorrelation, and after accounting for spatial dependence, the effect of GPP on SOC was weak and temporally inconsistent, reinforcing this decoupling. The integrated spatial analysis identified distinct functional regimes, with ecological hotspots concentrated predominantly in forest ecosystems and low-functionality regimes strongly associated with pasturelands. These findings demonstrate that ecosystem productivity and soil carbon storage exhibit distinct spatial and functional responses across the landscape. Integrating these complementary dimensions of ecosystem carbon functioning can support conservation, ecological restoration, and carbon-oriented environmental planning in fragmented tropical landscapes.