Evaluating carbon stocks in soils of fragmented Brazilian Atlantic Forests (BAF): How soil features and different methodologies influence its assessment

Abstract

Brazil’s Atlantic Forest (BAF) is a highly fragmented, strategic environmental and socio-economic region that represents the fourth biodiversity hotspot while also producing many commodities that are exported globally. Human disturbance plays a pivotal role as a driver of BAF’s soil dynamics and behaviors. The soils below Riparian Forests (RFs) and some Semideciduous Primary Forests (SFs) were characterized by high to moderate resilience, with improved chemical properties as human disturbance decreased. The Transitional Forest to Cerrado (TFC) had the worst soil conditions. Accordingly, SOCs stocks and soil carbon credits (SCC) increased from TFC << SFs < RFs. In BAF soils, measurements of SOC quantity and behavior should be conducted to at least 1 m soil depth to avoid unreliable data. Furthermore, quantifying SOC with a CHN analyzer was more reliable than other methods. A positive feedback was observed between soil and BAF vegetation, with human disturbance strongly affecting it and related SOCs dynamics. Soil development decreased as human disturbance increased, thus negatively affecting SOC. Soils in the BAF require a long time to recover after the end of human disturbance, thus suggesting that preservation strategies should be prioritized in remnant BAF fragments.