| 高寒灌丛退化演替过程对生态系统呼吸温度敏感性的影响 |
| 摘要点击 1921 全文点击 1244 投稿时间：2014-07-11 修订日期：2014-10-13 |
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| 中文关键词 高寒灌丛 退化演替 生态系统呼吸 Q10值 |
| 英文关键词 alpine Potentilla fruticosa scrub degradation succession ecosystem respiration Q10 value |
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| 中文摘要 |
| 放牧是高寒草甸退化演替过程中最主要人为驱动力之一. 为定量研究高寒草甸不同退化阶段生态系统呼吸速率的温度敏感性,本研究于2003年7月~2004年7月在中国科学院海北高寒草甸生态系统研究站,利用密闭箱-气相色谱法观测了高寒灌丛不同退化阶段生态系统呼吸速率季节变化. 结果表明: ①高寒灌丛不同退化阶段生态系统呼吸速率季节变化均表现为单峰曲线,最大值出现在草盛期8月,最小值出现在冬季10~次年4月. 退化演替过程显著降低了高寒灌丛生态系统呼吸速率. 观测期灌丛(GG)、丛间草甸(GC)和裸地(GL)的生态系统呼吸速率变化范围分别为34.21~1168.23、2.30~1112.38和20.40~509.72 mg·(m2·h)-1,灌丛(GG)呼吸速率平均值分别是丛间草甸(GC)和裸地(GL)的1.29倍和2.56倍. ②温度是生态系统呼吸速率的主要影响因子,可以解释系统呼吸速率25%~79%以上的变异. 退化演替过程显著地改变了生态系统呼吸速率与温度的相关性,当地表植被消失,灌丛退化为次生裸地后,生态系统呼吸速率与各温度指标Ts、Td、Ta之间的相关性(R2)分别降低47.23%、46.95%和55.28%. ③Q10值在冷暖季节差异显著(P<0.05),表现为冷季>暖季. 退化演替过程改变了生态系统呼吸的温度敏感性. 观测期灌丛(GG)、丛间草地(GC)和裸地(GL)Q10值分别为2.38、2.91和1.62,与灌丛(GG)相比,丛间草甸(GC)Q10值增加了22.26%,而裸地(GL)Q10值降低了31.93%. |
| 英文摘要 |
| Grazing is one of the main artificial driving forces for the degradation succession process of alpine meadow. In order to quantitatively study the temperature sensitivity of alpine meadow ecosystem respiration in different degradation stages, we conducted the research in Haibei Alpine Meadow Ecosystem Research Station, CAS from July 2003 to July 2004. The static chamber-chromatography methodology was used to observe the seasonal changes of alpine scrub ecosystem respiration flux during different degradation stages. The results showed that: ①The seasonal changes of ecosystem respiration flux in different degradation stages of alpine shrub presented a unimodal curve. The maximum appeared in August and the minimum appeared during the period from October to next April. The degradation succession process significantly decreased the ecosystem respiratory CO2 release rate. The respiratory rate ranges of alpine Potentilla fruticosa scrub (GG), Kobresia capillifolia meadow (GC) and bare land (GL) were 34.21-1168.23, 2.30-1112.38 and 20.40-509.72 mg·(m2·h)-1, respectively. The average respiration rate of GG was 1.29 and 2.56 times of that of GC and GL, respectively; ② Temperature was the main factor that affected the ecosystem respiration rate, and contributed 25%-79% of the variation of the ecosystem respiration. The degradation succession process significantly changed the correlation between ecosystem respiration rate and temperature. The correlation(R2)between ecosystem respiration rate and each temperature indicator (Ts, Td and Ta) was reduced by 47.23%, 46.95% and 55.28%, respectively when the ground vegetation disappeared and the scrub was degraded into secondary bare land; 3The difference of Q10 between warm and cool seasons was significant (P< 0.05), and the value of cold season was larger than that of warm season. Degradation succession process apparently changed the temperature sensitivity of ecosystem respiration. The Q10 values of GG, GC and GL were 2.38, 2.91 and 1.62, respectively. Q10 of GC was increased by 22.26% and that of GL was decreased by 31.93% compared with that of GG. |
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