放牧和封育条件下科尔沁沙地小叶锦鸡儿群落土壤种子库特征

以科尔沁沙地小叶锦鸡儿群落为研究对象,对比分析了放牧干扰和不同封育年限下土壤种子库特征。结果表明:①放牧和封育样地土壤种子库均以一年生植物为主,物种丰富度没有明显差异;②放牧样地土壤种子库密度为(3 475±519)粒/m2,封育6年和封育12年样地土壤种子库密度分别为(20 241±1 714)粒/m2和(28 777±3 946)粒/m2,显著高于放牧样地;③Shannon-W iener多样性指数、S impson多样性指数和P ielou均匀度指数在放牧样地分别为1.36,0.68和0.56,并随着封育年限的增加而降低;④放牧和封育样地土壤种子库主要分布于0~2 cm的土壤表层,封育样地各层的种子库密度均显著高于放牧样地;⑤放牧和封育样地土壤种子库均为聚集分布,但放牧样地种子库的空间异质性高于封育样地。

Characteristics of Soil Seed Bank of Caragana microphylla Community under the Grazing and Enclosure Conditions in Horqin Sandy Land

In this paper, the characteristics of soil seed bank of Caragana microphylla community under the grazing and enclosure conditions in Horqin Sandy Land, northeast Inner Mongolia, China were comparatively studied. The results are as follows: (1) The species of soil seed bank were dominated by the annual plants, and there was no significant difference in species richness between the grazed and fenced plots; ( 2) The seed density of soil seed bank in the grazing steppe was 3 475 ±519 seeds · m~(-2), it was 20 241 ±1 714 seeds · m~(-2) in the plots fenced for 6 years and 28 777 ±3 946 seeds · m~(-2) in the plots fenced for 12 years, and it was significantly higher in the fenced plots than that in the grazed plots; (3) The indexes of Shannon-Wiener and Simpson species diversity and Pielou evenness in the grazed plots were 1. 36, 0. 68 and 0. 56 respectively, and they were decreased with the increase of fenced time in the fenced plots; (4) Vertically, most seeds were found in topsoil of 0 ～2 cm in all plots, but the seed density of soil seed bank in all soil layers in fenced plots were significantly higher than that in the grazed plot; ( 5 ) The seeds were in an obvious aggregation distribution pattern in all plots, but the spatial heterogeneity of soil seed bank in the grazed plots was significant higher than that in the fenced plots.