The ecosystem carbon sink implications of mountain forest expansion into abandoned grazing land: The role of subsoil and climatic factors

编号 030019104

推送时间 20190617

研究领域 森林经理 

年份 2019 

类型 期刊 

语种 英语

标题 The ecosystem carbon sink implications of mountain forest expansion into abandoned grazing land: The role of subsoil and climatic factors

来源期刊 SCIENCE OF THE TOTAL ENVIRONMENT

期 第191期

发表时间 20190401

关键词 Land-use change;  Woody encroachment;  Carbon sequestration;  Soil carbon pools;  Italy;  Winter air temperatures; 

摘要 Woody encroachment is a widespread phenomenon resulting from the abandonment of mountain agricultural and pastoral practices during the last century. As a result, forests have expanded, increasing biomass and necromass carbon (C) pools. However, the impact on soil organic carbon (SOC) is less dear. The main aim of this study was to investigate the effect of woody encroachment on SOC stocks and ecosystem C pools in six chronosequences located along the Italian peninsula, three in the Alps and three in the Apennines. Five stages along the chronosequences were identified in each site. Considering the topsoil (0-30 cm), subsoil (30 cm-bedrock) and whole soil profile. the temporal trend in SOC stocks was similar in all sites, with an initial increment and subsequent decrement in the intermediate phase. However, the final phase of the woody encroachment differed significantly between the Alps (mainly conifers) and the Apennines (broadleaf forests) sites, with a much more pronounced increment in the latter case. Compared to the previous pastures, after mature forest (>62 years old) establishment, SOC stocks increased by: 2.1(mean) +/- 18.1(sd) and 50.1 +/- 25.2 Mg C.ha(-1) in the topsoil, 7.3 +/- 17.4 and 93.2 +/- 29.7 Mg C.ha(-1) in the subsoil, and 9.4 +/- 24.4 and 143.3 = 51.0 Mg C.ha(-1) in the whole soil profile in Alps and Apennines, respectively. Changes in SOC stocks increased with mean annual air temperature and average minimum winter temperature, and were negatively correlated with the sum of summer precipitation. At the same time, all other C pools (biomass and necromass) increased by 179.1 +/- 51.3 and 304.2 +/- 67.6 Mg C.ha(-1) in the Alps and the Apennines sites, respectively. This study highlights the importance of considering both the subsoil, since deep soil layers contributed 38% to the observed variations in carbon stocks after land use change, and the possible repercussions for the carbon balance of large areas where forests are expanding, especially under pressing global warming scenarios. (C) 2019 Elsevier B.V. All rights reserved.

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