作 者 ：窦荣鹏,江洪*,余树全*,马元丹,郭培培,宋新章
期 刊 ：生态学报 2010年 30卷 16期 页码：4521~4528
Keywords:litter, decomposition, mid-subtropical area, tropical area, global change,
摘 要 ：选取亚热带6个树种马尾松（Pinus massoniana）、毛竹（Phyllostachys heterocycla）、水杉（Metasequoia glyptostroboides）、木荷（Schima superba）、青冈（Cyclobalanopsis glauca）和苏铁（Cycas revoluta）的凋落物，在亚热带的千岛湖和热带的尖峰岭进行凋落物分解实验，研究不同气候带下凋落物的分解特征。两样地的年均气温和降水为主要差异，年均温差达3.0℃。结果表明：两个样地凋落物的分解速率顺序为：毛竹﹥木荷﹥青冈﹥马尾松﹥水杉﹥苏铁，尖峰岭样地6个树种95%分解所需的时间集中在3.22-8.81a，千岛湖样地95%分解所需的时间为4.61-14.27a。6种凋落物叶的分解速率尖峰岭显著大于千岛湖（P<005）。用尖峰岭的气候条件来模拟千岛湖气候变暖后的状况，凋落物分解的分解速率将提高43.08%-95.65%，凋落物的95%分解时间将缩短30.15%-48.85%。凋落物分解的表观Q10在3.30-9.35之间。在千岛湖样地凋落物的分解速率（k值）与初始氮含量呈显著正相关（P <0.05），与木质素含量呈显著负相关（P <0.05）；在尖峰岭样地，凋落物的分解速率与凋落物基质质量的各因子相关性均不显著。氮含量和木质素含量在中亚热带地区是预测凋落物分解和失重的良好指标，在热带地区气候因子对凋落物分解的控制作用较强于凋落物初始基质质量的控制作用。
Abstract:Global change is becoming one of central issue in broadly disciplines. Litter decomposition is a critical pathway of nutrient cycling in forests, and it plays an important role in linking aboveground and belowground processes of forest ecosystems. Global warming could have complicated effects on litter decomposition in terrestrial ecosystems. Although litterfall composition and dynamics had been widely studied. However the influence of global warming on the litterfall decomposition is poorly understood, so our objective was to explore the effects of global warming on the litterfall decomposition in Mid-subtropical and tropical China. The leaf litter of six main tree species in subtropical and tropical China, including Pinus massoniana, Phyllostachys heterocycla, Metasequoia glyptostroboides, Schima superba, Cyclobalanopsis glauca, Cycas revoluta, were selected and their decomposition rates were measured by litterbag in two sites (Qiandaohu in Zhejiang Province and Jianfengling in Hainan Province). The two sites have similar soil types and slope aspect. The annual mean temperature with the difference of 3.0℃ and mean annual precipitation between two sites. The decomposition experiment was conducted with nylon bag and the leaf litter were collected in Lin’an County of Zhejiang Province, in March of 2006. These material of leaf litter had been drought at 80℃ and analyzed their N, P, K, C and lignin initial contents variation. We packed them with 216 nylon bags, then placed to the ground surface of evergreen broad-leaf forest of Zhejiang Province and tropical rain forest of Hainan Province. Eighteen bags were take out once a month. The experiment period was about two years. When the litter bags were take out, they were clean and dry, The weight loss rate were measured, and calculated the decomposition rate. The results indicate that the order of litter decomposition rate was Phyllostachys heterocycla > Schima superba > Cyclobalanopsis glauca > Pinus massoniana > Metasequoia glyptostroboides > Cycas revolute both in Jianfengling and Qiandaohu. The 95% decomposition time ranges from 3.22 to 8.81 in Jianfengling, and from 4.61 to 14.27 in Qiandaohu. The decomposition rate in Jianfengling is faster than it is in Qiandaohu. The leaf litter decomposition of Schima superba and Cyclobalanopsis glauca are especially faster in Jianfengling than in Qiandaohu. The litter decomposition rate of Phyllostachys heterocycla is the fastest, and its decomposition rate is higher than other species. The difference between Jianfengling and Qiandaohu also was significant (P <0.05). As climate warming in the future, assuming the condition of Qiandaohu will be change to like Jianfengling, the litter decomposition rate will increase 43.08%-95.65%, the 95% decomposition time will shorten 30.15%-48.85%. The ranges of Q10 will be from 3.30 to 9.35, based on the basis of temperature difference between two sites, ranges We also found that annual decomposition rates of leaf litter in Qiandaohu was significantly correlated with the initial N and lignin concentration (P <0.05), The relationship between decomposition rate and litter substrate quality was not significant in Jianfengling site. Therefore, the initial N and lignin concentration of leaf litter could be the good indictors of litter decomposition rate in mid-subtropical area.
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