Rodtassana Chadtip, Unawong Weerapong, Yaemphum Siriphong, Chanthorn Wirong, Chawchai Sakonvan, Nathalang Anuttara, Brockelman Warren Y, Tor-Ngern Pantana
Department of Botany Faculty of Science Chulalongkorn University Bangkok Thailand.
Center of Excellence on Hazardous Substance Management Chulalongkorn University Bangkok Thailand.
Ecol Evol. 2021 Oct 19;11(21):15430-15443. doi: 10.1002/ece3.8248. eCollection 2021 Nov.
Soil respiration (SR) in forests contributes significant carbon dioxide emissions from terrestrial ecosystems and is highly sensitive to environmental changes, including soil temperature, soil moisture, microbial community, surface litter, and vegetation type. Indeed, a small change in SR may have large impacts on the global carbon balance, further influencing feedbacks to climate change. Thus, detailed characterization of SR responses to changes in environmental conditions is needed to accurately estimate carbon dioxide emissions from forest ecosystems. However, data for such analyses are still limited, especially in tropical forests of Southeast Asia where various stages of forest succession exist due to previous land-use changes. In this study, we measured SR and some environmental factors including soil temperature (ST), soil moisture (SM), and organic matter content (OM) in three successional tropical forests in both wet and dry periods. We also analyzed the relationships between SR and these environmental variables. Results showed that SR was higher in the wet period and in older forests. Although no response of SR to ST was found in younger forest stages, SR of the old-growth forest significantly responded to ST, plausibly due to the nonuniform forest structure, including gaps, that resulted in a wide range of ST. Across forest stages, SM was the limiting factor for SR in the wet period, whereas SR significantly varied with OM in the dry period. Overall, our results indicated that the responses of SR to environmental factors varied temporally and across forest succession. Nevertheless, these findings are still preliminary and call for detailed investigations on SR and its variations with environmental factors in Southeast Asian tropical forests where patches of successional stages dominate.
森林中的土壤呼吸（SR）是陆地生态系统中二氧化碳排放的重要贡献者，并且对环境变化高度敏感，这些变化包括土壤温度、土壤湿度、微生物群落、地表凋落物和植被类型。事实上，土壤呼吸的微小变化可能会对全球碳平衡产生重大影响，进而影响对气候变化的反馈。因此，需要详细描述土壤呼吸对环境条件变化的响应，以便准确估算森林生态系统中的二氧化碳排放量。然而，用于此类分析的数据仍然有限，特别是在东南亚的热带森林中，由于先前的土地利用变化，存在着不同阶段的森林演替。在本研究中，我们在三个演替阶段的热带森林中，于湿润期和干燥期测量了土壤呼吸以及一些环境因素，包括土壤温度（ST）、土壤湿度（SM）和有机质含量（OM）。我们还分析了土壤呼吸与这些环境变量之间的关系。结果表明，湿润期和老龄森林中的土壤呼吸较高。虽然在较年轻的森林阶段未发现土壤呼吸对土壤温度有响应，但老龄森林的土壤呼吸对土壤温度有显著响应，这可能是由于包括林窗在内的不均匀森林结构导致土壤温度范围较广。在所有森林阶段中，土壤湿度在湿润期是土壤呼吸的限制因素，而在干燥期土壤呼吸随有机质含量显著变化。总体而言，我们的结果表明，土壤呼吸对环境因素的响应在时间上和森林演替过程中有所不同。然而，这些发现仍然是初步的，需要对东南亚热带森林中土壤呼吸及其随环境因素的变化进行详细研究，这些地区以演替阶段的斑块为主。
