South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Environ Manage. 2011 Dec;48(6):1189-97. doi: 10.1007/s00267-011-9758-5. Epub 2011 Oct 8.
The response of soil respiration to short-term environmental factors changes has been well studied, whereas the influences of long-term soil microclimate changes on soil respiration are still highly unclear, especially in tropical ecosystems. We hypothesized that soil carbon accumulation in southern China, especially in mature forest during recent years, partly resulted from reducing soil respiration rates. To test this hypothesis, we analyzed the temporal trends and variations of air temperature, soil temperature and soil water content (hereafter referred to as SWC), and then estimated soil respiration rates in the 1980s and 2000s with soil temperature and SWC by regression model in three subtropical forests which are at early-, mid-, and advanced-successional stages, respectively, in Dinghushan Nature Reserve (hereafter referred to as DNR) in southern China. The annual mean ambient air temperature increased by 1.03 ± 0.15°C in the last 50 years (1954-2007) in DNR. Rainfall amount in the corresponding period did not change significantly, but rainfall pattern changed remarkably in the last three decades (1978-2007). Soil temperature is correlated with ambient air temperature. The average SWC was 36.8 ± 8.4%, 34.7 ± 8.1% and 29.6 ± 8.1% in the 1980s, and then dropped sharply to 23.6 ± 2.9%, 20.5 ± 4.2% and 17.6 ± 3.9% in the 2000s, for the advanced, mid- and early-successional forests, respectively. Concurrent changes of soil temperature and SWC may have a negative effect on soil respiration rates for all three forests, implicated that soil respiration may have a negative feedback to regional climate change and carbon could be sequestered in subtropical forests in southern China.
土壤呼吸对短期环境因素变化的响应已经得到了很好的研究，而长期土壤小气候变化对土壤呼吸的影响仍然高度不清楚，特别是在热带生态系统中。我们假设，近年来中国南方，特别是成熟森林中的土壤碳积累部分归因于土壤呼吸速率的降低。为了检验这一假设，我们分析了空气温度、土壤温度和土壤水分含量（以下简称 SWC）的时间趋势和变化，并在过去 50 年（1954-2007 年）中，在鼎湖山自然保护区（DNR）的三个分别处于早期、中期和晚期演替阶段的亚热带森林中，通过回归模型分析了 20 世纪 80 年代和 2000 年代的土壤呼吸速率。在过去的 50 年（1954-2007 年）中，鼎湖山自然保护区的年平均环境空气温度增加了 1.03 ± 0.15°C。同期降雨量没有明显变化，但过去三十年降雨量模式发生了显著变化。土壤温度与环境空气温度相关。在 20 世纪 80 年代，先进、中期和早期演替森林的平均 SWC 分别为 36.8 ± 8.4%、34.7 ± 8.1%和 29.6 ± 8.1%，然后急剧下降到 23.6 ± 2.9%、20.5 ± 4.2%和 17.6 ± 3.9%，在 2000 年代。三个森林的土壤温度和 SWC 的同时变化可能对所有三个森林的土壤呼吸速率产生负面影响，这表明土壤呼吸可能对区域气候变化产生负反馈，而中国南方的亚热带森林可能会储存碳。
