风沙黄土区排土场不同恢复类型植物群落与土壤种子库特征

风沙黄土区排土场作为一种人造生态系统,自然条件恶劣,土壤贫瘠,植被恢复困难。为了探明有效的人工促进植被恢复措施,采用植被调查与种子库萌发试验相结合的方法,通过研究不同植被类型地上植物群落与土壤种子库特征及二者的关系,探讨了其植被恢复效益及潜力。结果表明:研究区人工植被恢复下地上植物群落中共47种植物,分属16科40属,土壤种子库共14种植物,分属5科13属,其中均以禾本科、菊科、藜科、豆科占主导地位; 灌木植被的地上植被和土壤种子库的物种多样性均表现为最优; 地上植被与土壤种子库密度的变化范围为88.48～495.47株/m²,74.74～1422.91粒/m²,且均在草地类型下最大。土壤种子库和地上植被的相似性普遍较低,相似性系数仅为0.16～0.23。因此,风沙黄土区排土场的植被恢复与重建需要加强保护与管理,可以考虑构建以草灌配置为主的人工植被恢复模式,保障群落的恢复潜力,并提高群落多样性与稳定性,亦可考虑引入外源种子库提升群落恢复的潜力。

Community and Soil Seed Bank Characteristics of Different Vegetation Restoration Types in Aeolian Sandy Loess Dumps

As an artificial ecosystem, the natural conditions of the dump in the aeolian loess region are severe and the soil is barren. The characteristics and relationship between aboveground vegetation communities and soil seed bank of different vegetation types were studied by using the method of vegetation investigation and seed bank germination experiment, and the benefit and potential of vegetation restoration were discussed. There are 47 species of plants belonging to 16 families and 40 genera in the aboveground vegetation community under the artificial vegetation restoration in the study area. The soil seed bank consists of 14 species belonging to 5 families and 13 genera, among which Gramineae, Compositae, Chenopodiaceae and Leguminosae are dominant. The species diversity of aboveground vegetation and soil seed bank of shrubbery are the best. The density of soil seed bank and aboveground vegetation variy from 88.48 to 495.47 plants/m² and from 74.74 to 1422.91 seeds/m², and they are the largest under grassland type. The similarity coefficient of soil seed bank and aboveground vegetation ranges from 0.16 to 0.23. Therefore, it is necessary to strengthen the protection and management for the vegetation restoration and reconstruction of the dumping site in the aeolian loess area. The artificial grassland and Shrub should be considered as the main factors to improve the community diversity and stability, and different provenances should be introduced to increase the community restoration potential.