Reserves and species diversity of soil seed banks in four types of forest on Mt. Taibai, Qinling Mountains

Abstract

The soil seed bank represents the pool of potential species for a plant community. It plays a critical role in community succession and maintenance of the community structures and functions. We analyzed the distribution of soil seed banks and their characteristics in four forest types: Larix chinensis forest, Betula utilis forest, Quercus aliena var. acuteserrata forest, and Abies fargesii forest based on 240 samples collected on the southern slope of Mt. Taibai, Qinling Mountains, Central China. The results are summarized as follows: (1) the soil seed bank reserve of B. utilis forest was the largest one (1.7677×104 ind./m2), while L. chinensis forest the smallest (1.742×103 ind./m2). Seed characteristics influenced soil seed bank reserves. (2) the seed bank of Q. aliena var. acuteserrata forest contained 50 species, which was the highest of the four forest types. The seed reserves were highest in litter layer, followed by that in humus layer and subsurface soil layer. The seed banks of deciduous broad-leaved forests exhibited higher dominance and lower evenness than those of coniferous forests. The seed bank evenness index was highest in A. fargesii forest. (3) the reserves and density of seed banks showed similar patterns along the altitudinal gradient and in the four forest types. In this study, the soil samples were divided into three layers: litter layer, humus layer and subsurface soil layer. This sampling method improved on previous methods, which sampled soil at a fixed soil depth. Having taken the characteristics of soils into account, seed density was a better indicator of the soil seed bank characteristics than the seed reserve.