川西亚高山/高山森林大型土壤动物群落多样性及其对季节性冻融的响应

Soil macro-fauna community diversity and its response to seasonal freeze-thaw in the subalpine/alpine forests of western Sichuan

为了解季节性冻融及其变化对土壤动物群落特征的影响,于2008年11月-2009年10月的冬季(土壤冻融期、冻结期和融化期)及植被生长季节,研究了不同岷江冷杉(Abies faxoniana)林的大型土壤动物群落特征。共采集大型土壤动物10,763只,隶属于91科。冬季与生长季节土壤动物群落结构存在显著差异:冬季以长角毛蚊科幼虫和尖眼蕈蚊科幼虫为优势类群,大蚊科幼虫、苔甲科和蠓科幼虫等为常见类群;而生长季节以蚁科、隐翅甲科、长角毛蚊科幼虫和异蛩目为优势类群,原铗叭科、蝇科幼虫和石蜈蚣目等为常见类群。土壤动物群落个体密度、类群数量和多样性指数(H')随冻融格局变化表现出先降低后升高的趋势,在土壤融化期达到了一个明显高峰值。冬季土壤动物以腐食性类群为主,捕食性和植食性功能类群在融化末期(4月25日)和生长季节初期(5月25日)显著增加。研究结果表明冻融循环和冻结作用显著影响土壤动物群落结构,季节转换过程中土壤动物群落的变化可能对深入认识冬季和生长季节生态过程的相互关系具有重要意义。

Abstracts：In order to understand the effects of seasonal freeze-thaw on the structure of soil macro-faunal community,we conducted a field experiment in three representative fir（Abies faxoniana） forests at different elevations in the subalpine/alpine forests of western Sichuan.The composition,abundance,and diversity of soil macro-faunal community were investigated in winter（including onset of soil freezing period,soil frozen period,and soil thawing period） and growing season of vegetation from November 2008 to October 2009.A total of 10,763 individuals were collected and,according to preliminary identification,they belonged to 91 families.There were obvious differences in soil macro-faunal community structure between winter and growing season.The dominant groups in winter consisted of Hesperinidae and Sciaridae,while the ordinary groups consisted of Tipulidae,Scydmaenidae and Ceratopogonidae.However,the dominant groups in growing season consisted of Formicidae,Staphylinidae,Hesperinidae and Spirostreptida,and the ordinary groups consisted of Lithobiomorpha,Projapygidae and Muscidae.Moreover,individual density,number of taxonomic groups,and Shannon-Wiener index of soil macro-faunal community tended to decrease and then increase to a distinct peak in the soil thawing period as seasonal freeze-thaw proceeded in winter.In addition,saprozoic species dominated the functional groups in winter,and the proportion of predatory and phytophagous soil macro-faunal species increased in late soil thawing（April 25） and early growing season（May25）.Our results suggest that seasonal freeze-thaw and freezing events significantly influence the structure of soil faunal community,and that changes in the soil faunal community during the transitional period between late soil thawing and the early growing season may have important influences on ecological processes.