Anthropogenic Disturbances Superimpose Climate Effects on Soil Organic Carbon in Savanna Woodlands of Sub‐Saharan Africa

作者：Fernando Caldeira Jorge, N. Mutwale‐Mutale, Alexandra Sandhage‐Hofmann, Matthias Braun, Armindo Cambule, Amancio Nhantumbo, Lydia M. Chabala, C. Shepande, Benson H. Chishala, Sá Nogueira Lisboa, Mario Tauzene Afonso Matangue, Michael W. Schmidt, Wulf Amelung · 发表于：Global Biogeochemical Cycles · 年份：2025 · DOI：10.1029/2023gb008086 · 被引用次数：7 · 研究领域：Ecology and Vegetation Dynamics Studies、Soil Carbon and Nitrogen Dynamics、Rangeland Management and Livestock Ecology

Abstract Savanna ecosystems in sub‐Saharan Africa harbor substantial yet relatively unexplored reserves of soil organic carbon (SOC). Our study unravels for the first time the interplay between climate, reference soil groups, and anthropogenic disturbances in shaping SOC dynamics in these ecosystems. We analyzed SOC along climosequences in natural woodlands in Mozambique and Zambia, with mean annual temperature (MAT) of 20–24°C, and mean annual precipitation (MAP) of 365–1,227 mm. Anthropogenic disturbances were assessed through comprehensive field surveys and remote sensing of vegetation and indices change. MAT and evapotranspiration (PET) had no discernible effect on SOC. Bulk SOC, particulate organic matter, and mineral‐associated organic matter stocks in the topsoil (0–10 cm) increased with MAP, though this relationship was not significant for the subsoil. MAP explained only 35% of topsoil SOC variability, limited by anthropogenic disturbances, which raised SOC stocks in the dry savanna but resulted in SOC losses at >600 mm MAP, which even extended into subsoil. For sites with little disturbance in the past decades, there were soil group‐specific effects of MAP on SOC, explaining up to 85% of data variability. In disturbed sites, human presence altered the carbon (C) balance to an extent that, as rough estimate, could account for up to 2.6 Gt CO 2 ‐C loss over 20 years in wetter sites, with another 2.4 Gt CO 2 ‐C at risk as populations spread into these otherwise prist...