关键词: 含水率反演, 图像, 水胁迫, 檀香

Abstract: We examined the spatiotemporal variations in taxonomic composition and diversity of soil microarthropod communities under four vegetation types along the altitude gradient on the eastern slope of Gongga Mountain. The vegetation types included evergreen broad-leaved forest (EBF, at an altitude of 1930 m), deciduous broad-leaved forest (DBF, 2343 m), coniferous and broad-leaved mixed forest (CBF, 2780 m), and dark coniferous forest (DCF, 3160 m). Soil microarthropods were investigated in March, May, July, October and December, 2012. A total of 8581 individuals of soil microarthropods were collected and classified into 8 classes, 28 orders, 114 families and 145 taxa or genera. The microarthropods were dominated by Paranurophorus, which accounted for 24.26% of the total individuals. The microarthropod communities on the eastern slope of Gongga Mountain showed higher taxonomic richness and unique zonal characteristics compared to those of forest ecosystems in subtropical and temperature zones. The results of principal component analysis and similarity indices showed that soil microarthropod community structure were similar among the four forest types, but the similarity declined with the increasing of relative altitude among the different forests. The density, richness and Shannon index of soil microarthropod communities decreased with increasing altitude, with lower richness and Shannon index of dark coniferous forest than those of the other forests. Moreover, the density, richness, Shannon index and Simpson index of soil microarthropod communities were higher in March and December than in May, July and October, with significant differences among the sampling months. Soil organic matter, available P, pH, soil temperature and moisture were the main factors driving the spatial distribution of the density and diversity of soil microarthropods. Our results indicated that soil microarthropod community on the eastern slope of Gongga Mountain had higher taxonomic richness and unique zonal characteristics, and their community structure, density and diversity index were more sensitive to seasons than to vegetation types.

Key words: sandalwood, water content inversion, water stress, image