黄土高原地区黄龙山白皮松林地土壤种子库研究

Soil seed banks in the Pinus bungeana forestland of the Huanglong Mountains on the Loess Plateau

采用萌发法和分粒结合的方法对陕西省黄龙山地区白皮松Pinus bungeana林地土壤种子库的物种组成、垂直分布和多样性等群落生态因子进行了对比研究。结果表明：黄龙山地区白皮松林地土壤种子库萌发期和落种期2个不同物候期的物种结构相似,全年土壤种子库共有物种44种,隶属34个属26个科;包括乔木、灌木、草本和藤本4种类型。将土壤种子库分为0~5,5~10,10~15 cm等3个层次,不同土壤层次间种子个体数和物种数差异极显著（P〈0.01）,均呈现上层（0~5 cm）〉中层（5~10 cm）〉下层（10~15 cm）的趋势。研究的12个样地土壤种子库的Margalef丰富度指数、Shannon-Wiener多样性指数和Pielou均匀度指数平均值分别为3.87,3.63和1.15,受人为活动影响强烈的样地多样性指数明显低于远离耕作区的样地。在整个的演替更新过程中,白皮松的更新能力强于其他乔木树种,主要表现在幼苗幼树和种子数占绝对优势,草本植物的种子数量和物种数都高于木本植物,在乔木树种更新能力弱的样地个别草本物种迅猛繁殖,导致物种多样性和均匀度降低。

This study aims to understand the composition structure and function characteristics of the soil seed banks in the Pinus bungeana forestland of the Huanglong Mountain area. A comparative study in species composition, vertical distribution, diversity, and other community ecological factors of soil seed banks in P/nus bungeana forests, which was undertaken by adopting the germination and grain combining methods. Treatments included three layers： 0-5, 5-10, and 10-15 cm layers and analysis included three indexes： the Margalef abundance, Shannon-Wiener diversity, and Pielou evenness degree. Regeneration and succession for four structural types namely, trees, shrubs, herbs, and lianas were also compared（12 plots, 3 replications）. The results indicated that the germination period was identical to the seed period in species structure. The soil seed bank contained 44 species belonging to 34 genera and 26 families in 2009. For individual seed number and species number, a significant difference （P〈0.01） was found among soil layers with： 0-5 cm 〉 5-10 cm 〉 10-15 cm. Index averages were Margalef abundance： 3.87, Shannon-Wiener diversity index： 3.63, and Pielou evenness degree index： 1.15. For regeneration and succession, P. bungeana had a stronger regeneration capability with seeds at 39.2% of all tree species. Also, the herbaceous plants were 19.00% more than the woody plants in seeds and 36.36% in species number. Our results show there are significant differences in the vertical distribution of soil seed banks, and the composition of species remained relatively stable in the Huan-glong Mountain area. [Ch, 3 fig. 1 tab. 21 ref].