黄土丘陵沟壑区退耕地土壤种子库与地上植被的关系

Relationship between soil seed bank and aboveground vegetation in abandoned croplands on the Gullied-Hill Loess

土壤种子库与地上植被的耦合研究对于探索有效的植被恢复方法具有重要意义。通过野外调查和室内试验研究了黄土丘陵沟壑区退耕地土壤种子库与地上植被的关系。结果表明，地上植被的物种数（54种）多于土壤种子库中的物种数（28种），菊科、禾本科和豆科都是它们物种组成的主要植物；土壤种子库和地上植被的丰富度指数、多样性指数、生态优势度与退耕年限的相关性未达到显著水平，只有均匀度指数和退耕年限呈显著正相关关系；土壤种子库和地上植被的相似性比较小，相似性系数（CC）变化范围为0．143～0．414，平均为0．261。黄土丘陵沟壑区退耕地土壤种子库的物种数、丰富度指数和多样性指数均小于地上植被，这从一定程度上说明了该研究区土壤种子库在植被恢复中的潜力还比较小，植被恢复还需要适度的人为干预与调控。

Understanding the relationship between the soil seed bank and aboveground vegetation is very important for effective vegetation restoration. A field survey and laboratory experiment to study this relationship in abandoned croplands on the Gullied-Hill Loess showed that species number in the aboveground vegetation was greater than that in the soil seed bank. Most species were in the Compositae, Granimeae, and Leguminoseae. The richness, diversity index, evenness index and ecological dominance of the soil seed bank and aboveground vegetation were not all significantly related to the year since abandonment （with the exception of the evenness index of the soil seed bank）. Coefficients of species similarity between the soil seed bank and the aboveground vegetation ranged from 0. 143 to 0. 414 and the mean value was 0. 261.