关键词: 冬季生态学, 冻融循环, 生物多样性, Abies faxoniana

Abstract

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 (May 25). 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.

Key words: soil ecology, freeze-thaw cycle, biodiversity, Abies faxoniana