天津市“城-郊-乡”样带土壤种子库特征分析

为了解天津市不同地理位置土壤种子库物种组成和群落结构的变化,沿天津市设置＂城区—城郊—远郊＂的生态样带,在6个典型样地选取20个样方进行土壤种子库的采样工作并进行萌发试验。结果表明：土壤种子库的密度、物种组成及群落结构差异性明显,除趋势对应分析后分异出典型的城市土壤种子库、城郊土壤种子库、远郊土壤种子库3种类型。从远郊到城区,土壤种子库的密度递增,相似性指数也递增,而物种丰富度却递减。相比远郊地区,城区、城郊区土壤种子库物种丰富度损失率分别为66.67%、45.23%。城区因城市化水平较高及频繁的人为干扰致使土壤种子库物种呈现匀质化特点,物种多为一年生的耐踩踏草本。城郊区的多样性指数、生态优势度指数、均匀度指数最低,但是种子库密度较大,物种丰富,萌发种子中木本植物可观,适合用于进行植被恢复的试验研究。

Feature Analysis of Soil Seed Bank in Urban-Suburban-Rural Transect in Tianjin

In order to study the properties of species composition and community structure of soil seed banks in different geographic locations, 20 samples from 6 typical sites were collected along the urban-suburban-rural transect for the seed germination experiment. The seed density, species composition and community structure showed significant difference. Three obvious types were identified by DCA（Detrended Correspondence Analysis） ordination analysis：urban soil seed bank, suburban soil seed bank and rural soil seed bank. From rural area to urban area, the density and Sorensen index of soil seed bank showed an increasing trend, but species richness showed a decreasing trend.Compared to rural area, the rates of species richness in urban and suburban areas were decreased by 66.67% and45.23%, respectively. Urbanization promoted species homogenization. The suburban area had the lowest ShannonWiener Index, Ecological Dominance Index, and Pielou Evenness Index, but it had high density and species richness.Germinated seeds had a large number of woody seedlings, therefore, the suburban area could be considered for vegetation recovery study.