川西亚高山/高山森林凋落物分解过程中土壤动物群落结构及其多样性动态

Soil fauna community structure and diversity during foliar litter decomposition in the subalpine/alpine forests of western Sichuan

为进一步了解土壤动物对高寒森林凋落物分解的影响,于2011年11月至2012年10月在凋落物分解的不同时期即冻结前期、冻结期、融化期、生长季节初期、生长季节中期以及生长季节末期,采用凋落物分解袋法,研究了川西亚高山/高山森林代表性物种康定柳(Salix paraplesia)、方枝柏(Sabina saltuaria)、红桦(Betula albosinensis)和岷江冷杉(Abies faxoniana)凋落物中土壤动物的群落结构及其多样性动态.结果显示:(1)共捕获土壤动物7 082只,隶属2门9纲15目57科(类),不同物种凋落物中土壤动物捕获量差异显著,依次为岷江冷杉(36.01%)>红桦(29.19%)>康定柳(19.59%)>方枝柏(15.21%).(2)冻融季节土壤动物捕获量显著小于生长季节,但仍占到总捕获量的17.69%.(3)凋落物分解的不同时期,土壤动物优势类群差异显著,但主要以弹尾目和甲螨亚目为主.(4)土壤动物功能类群以菌食性(64.17%)最多,其次是捕食性(23.89%),植食性(8.94%)次之,腐食性(3.00%)最少.(5)土壤动物多样性受温、湿度影响显著,其Shannon-Wiener多样性指数与水热条件变化趋于一致.这些结果表明凋落物质量及水热条件综合作用于川西亚高山/高山森林凋落物分解过程中土壤动物群落结构及其多样性.

Our objective was to characterize the structure and diversity of soil fauna community during litter decomposition, and further expound the important effect of soil fauna to litter decomposition in cold forests. A field litterbag experiment was conducted in the subalpine/alpine forests of western Sichuan, China. Samples of air-dried leaf litter for Salix paraplesia, Sabina saltuaria, Betula albosinensis, and Abies faxoniana were placed in nylon litterbags （20 cm × 20 cm, 10 g per bag） of 3.00 mm mesh sizes. The structure and diversity of soil fauna community were investigated at different stages from November 2011 through October 2012, i.e., onset of freezing period, deep freezing period, thawing stage, early growing season, mid-growing season, and late growing season. A total of 7 082 individuals of soil fauna were collected, which according to preliminary identification, belonged to 2 phyla, 9 classes, 15 orders and 57 families. The individuals in different species litterbags were Fir （36.01%） 〉 Birch （29.19%） 〉 Salix （19.59%） 〉 Cypress （15.21%）. The individuals of soil fauna in growing season （82.21%） were significantly greater than that in freeze-thaw season （17.69%）. The dominant groups of various species litter at each period were different, but mainly Oribatida and Collembola. The functional group was mainly dominated by fungivore （64.17%）, with the order of other functional groups as predators （23.89%） 〉 phytophaga （8.94%） 〉 saprozoic （3.00%）. The Shannon-Wiener diversity index of soil fauna changed consistently with temperature and precipitation. These results showed that the structure and diversity of soil fauna community are influenced by hydrothermal conditions, which is of great importance in understanding the effect of soil fauna to litter decomposition.