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

Abstract

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.