CAS Workshop on Ecosystem Succession Theory and Practice of Ecological Restoration

热带亚热带森林凋落物交互分解的生态学实验比较研究* 

刘强^{1. 2}  彭少麟¹   毕华²  李志安¹  张洪溢²  马文辉²  李妮亚²

（¹中国科学院华南植物研究所，广州 510650；²海南师范学院生物系，海口 571158） 

摘要：为了检验全球变暖对森林凋落物分解的影响，我们在跨气候带的大尺度下进行森林凋落物的交互分解实验，分别在热带的尖峰岭和亚热带的鼎湖山选择了2个样地，它们有相似的海拔高度、土壤类型、年均降雨量及干湿季节律，位于中国东部南北样带内，热量梯度为主要驱动因子。气温为主要差异，达3.7度。各样地分别收集了10种当地的优势树种的凋落叶。其中2个样地各自的最优势种青皮和锥栗，2个样地均有的共同种荷木做为单种样。  10种凋落叶的等重量混合做为混合样，共计6类凋落叶。凋落叶样分别交互置于2个样地的林地地表。分解结果表明：6类凋落叶在尖峰岭的分解速率极显著地大于在鼎湖山的分解速率。凋落叶分解的表观Q₁₀在3.7—7.5范围内。证实在这个气温差范围内，凋落物分解加快的程度可达1.36—3.06倍。证明全球变暖会加强森林的物质循环功能。

6类凋落叶在尖峰岭样地分解中，单种样青皮和锥栗与其他种类都有显著差异，其余差异不显著，表明种类之间的差异不起主导作用，气候差异更为重要。在鼎湖山样地分解，单种样青皮和锥栗与其他种类都有显著差异，类似于在尖峰岭样地的情形，但种间差异更大，几乎各不相同，凋落物基质质量在分解中的作用较在尖峰岭样地的分解更为明显。可能意味着气温越高，基质质量不同的各种凋落叶在分解中的差异越小，基质质量对分解速率的作用相对降低。

在尖峰岭样地 (In site J) 分解的6种叶凋落物，头3个月失重很快，后几个月失重减缓，第3个月与第6个月差异不显著，其余都有显著差异。而在鼎湖山样地 (In site D)中，6种叶凋落物的失重随时间较为均衡的下降，各时间步长之间差异显著。

关键词：全球变暖；热带；亚热带；森林凋落物；交互分解 

Ecological experimental comparative study on the decomposition of tropical and subtropical forests’ leaf litter in reciprocal sites  

Liu Qiang^{1. 3}  Peng Shaolin¹  Bi Hua²  Li Zhi’an¹  Zhong Hongyi²  Ma Wenhui²  Li Niya²

(¹South China Institute of Botany, Chinese Academy of Sciences, Guangzhou 510650, China; ²Hainan Normal University, Haikou 571158, China) 

Abstract: In order to examine the effect of global warming on the decomposition of forest litter, we designed the experiment for decomposition of forest leaf litter in reciprocal sites across tropical and subtropical zones. Each one site was selected from Jiangfengling in tropical and Dinghushan in subtropical zone respectively. Both were located in the NSTEC (north-south transect in eastern China),in which the heat gradient along the transect was the main drive. They had similar altitudes, soil types, annual mean temperature and dry and wet seasoning. The difference of annual mean temperature was 3.7 degrees. Leaf litter of local ten dominant tree species were collected from the 2 sites respectively and divided into 6 types of litter samples, i.e. 2 single species litter samples of the most dominant tree species Vatica mangachapoi in site J and Castanopsis chinensis in site D, 2 single species litter samples of the common tree species Schima superba in both sites and 2 mixture litter samples of each 10 tree species litter equally weighted mixed. With the litter bag method the 6 types of leaf litter were decomposed on the ground of the two sites reciprocally. The results showed that the decomposition rates of the 6 litter types were extremely significantly larger in Jianfengling site than in Dinghushan site. Apparatus Q₁₀ were in the range of 3.7—7.5. It was shown that if temperature arising in the range litter decomposed as 1.36—3.06 times rapidly as non temperature arising. So it was proved that global warming will strengthen the matter circulation function of forest.

In site J the single species litter samples of Vatica mangachapoi and Castanopsis chinensis had significant difference with other types, and among the others the differences were not significant. It indicated that the variation of litter types did not play a dominant role in tropical, and the difference of temperature was more important. In site D the situation was similar in that the single species litter samples of Vatica mangachapoi and Castanopsis chinensis had significant difference with other types, while not similar in that among the other types of leaf litter almost all had significant differences. In the decomposition the substrate quality of leaf litter played a more important role in site D than in site J. It may mean that the higher the temperature the less difference in decomposition rates of the various litter types and less important of the litter quality in decomposition. 

In site J the decomposition of 6 types of leaf litter in first 3 months period were rapider than thereafter periods. The difference of mass remaining between the first 3 months and the second 3 months period was not significant and but the differences among the rest periods were significant. While in site D the mass loss of leaf litter were relatively even, the differences of mass remaining among each periods were significant.

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