The lack of robust scientific data still hinders estimates of soil and plant carbon (C) losses due to land-use changes in most dry tropical ecosystems. The present study investigated the effects of land-use and cover changes on total ecosystem C stocks in NE Brazil, aiming to quantify C losses after the removal of the native forest, known as Caatinga. The sampling design included the four main land-use/cover types (Dense Caatinga, Open Caatinga, Pastures and Crop fields) and the seven main soil classes (Arenosols, Acrisols, Regosols, Ferrasols, Luvisols, Planosols, and Leptosols), a combination that represents over 90% of the region. This design resulted in 192 sampling points (48 in each land-use), distributed proportionally to the area of occurrence of each soil class. In each sampling point, we determined C stocks in soil organic matter (SOM) and roots (to a depth of 1 m or rock layer), aboveground vegetation biomass (trees and herbs, separately), deadwood, and surface litter. Areas covered by Dense Caatinga store, on average, nearly 125 Mg ha⁻¹ of C. Most of this C is stored in the soil organic matter (72.1%), followed by aboveground biomass (15.9%), belowground biomass (7.3%), deadwood (2.9%), litter (1.3%), and herbaceous biomass (0.5%). The substitution of Dense Caatinga to plant pastures and crop fields caused losses of >50% of ecosystem C stocks, reaching almost 65 Mg ha⁻¹ of C, with nearly equal losses from the SOM and vegetation biomass compartments. Open Caatinga store nearly 30% less C than Dense Caatinga. Contrary to what was expected, the overall differences in C stocks between soil classes were not significant, with a few exceptions. We expect that the findings of this study will contribute to a more robust inventory of GHG emissions/removals due to land-use changes in NE Brazil and other dry tropical regions of the globe.

缺乏可靠的科学数据仍然阻碍了对大多数干旱热带生态系统中土地利用变化造成的土壤和植物碳（C）损失的估计。本研究调查了巴西东北部土地利用和覆盖变化对生态系统总碳储量的影响，旨在量化去除被称为Caatinga的原始森林后的碳损失。抽样设计包括四种主要的土地利用/覆盖类型（密集的Caatinga，Open Caatinga，牧场和作物田）和七个主要的土壤类别（Arenosols，Acrisols，Regosols，Ferrasols，Luvisols，Planosols和Leptosols）。占该地区90％以上。该设计产生了192个采样点（每种土地使用方式为48个），并与每种土壤类别的发生面积成比例地分布。在每个采样点 我们确定了土壤有机质（SOM）和根部（深度为1 m或岩石层），地上植被生物量（分别为树木和草药），枯木和表面垫料中的C储量。Dense Caatinga商店平均覆盖的面积约为125 Mg公顷C的^-1。大部分C储存在土壤有机质中（72.1％），其次是地上生物量（15.9％），地下生物量（7.3％），枯木（2.9％），凋落物（1.3％）和草本生物质（0.5％）。将Dense Caatinga替换为草场和农作物造成的生态系统碳储量损失> 50％，达到近65 Mg ha ^-1的C，而SOM和植被生物量隔室的损失几乎相等。开放的Caatinga商店的碳比Dense Caatinga的商店少近30％。与预期相反，土壤类别之间碳储量的总体差异不大，只有少数例外。我们预计，由于巴西东北部和全球其他干旱热带地区的土地利用变化，这项研究的结果将有助于建立更强大的温室气体排放/清除清单。