Mapping of soil carbon balances changes in the dry tropical forest ecosystem in Pernambuco Brazil

Abstract

Land use changes represent an important part of anthropic greenhouse gas emissions. Studies on the dynamics of carbon stock in soil and vegetation resulting from changes in land use in dry tropical areas are still scarce and practically absent in the Northeast region of Brazil. Combining field and remote sensing information with spatial analysis can contribute to understanding the spatial dynamics of carbon in the soil. Given this, we aimed to estimate and map carbon balances in the semiarid region of Pernambuco state, Brazil (86,135 km2). Maps of carbon stocks for soil and vegetation for 2000 and 2016 were created on a scale of 1: 100,000, stratified by land use and soil types. During the time-lapse of 16 years, 28% of the area carbon stocks (C) decreased in soil and vegetation, 57% had no significant changes and only 13% had increases. Most of the change was associated with converting the open native forest vegetation (Caatinga) into pastures. The net C loss was 291 million Mg, representing an average of 2 Mg ha-1 year-1 of C loss. Water bodies, urban areas, and other unclassified uses were not accounted for but amounted to only 2% of the area. Overall, the GIS method proved to be a fast and feasible approach to monitoring carbon balances derived from land use changes on a regional scale.