Xinjiang Production and Construction Corps Key Laboratory of Oasis Town and Mountain-basin System Ecology, Shihezi, 832000, China; College of Life Science, Shihezi University, Shihezi, 832003, China.
Xinjiang Production and Construction Corps Key Laboratory of Oasis Town and Mountain-basin System Ecology, Shihezi, 832000, China; College of Life Science, Shihezi University, Shihezi, 832003, China.
J Environ Manage. 2022 Sep 1;317:115468. doi: 10.1016/j.jenvman.2022.115468. Epub 2022 Jun 1.
Giant ragweed (Ambrosia trifida L.), an invasive weed, has an expanding distribution area and has recently started to spread in grasslands. This unusual event threatens grasslands worldwide. In this study, we aimed to evaluate the changes in the grassland soil seed banks caused by the giant ragweed invasion in Yili Valley, Xinjiang, China. Using the space-for-time substitution approach, we compared and quantified the soil seed bank communities in a grassland over eight years following giant ragweed invasion and after its removal. The results showed that the duration of invasion determined whether giant ragweed might pose a significant threat to the native seed bank community. Four years after the invasion, the in-site seed bank density of native community significantly decreased (30.44%), while the relative coverage of giant ragweed aboveground reached 83.75%. Furthermore, the species richness in the seed bank decreased significantly (12.36%), while the relative coverage of giant ragweed reached 100% six years after the invasion. Eight years after the invasion, the seed bank density and species richness of the native community decreased by 83.28% and 39.33%, respectively, whereby the seed banks tended to be homogeneous. After the removal of giant ragweed, the potential for regeneration was limited by the residual seed bank densities of the native community. Although the native seed bank density had increased significantly after three years of restoration, new growth was dominated by weedy species, rather than by the distinctive components of the grassland habitat. Our study clarifies the process by which giant ragweed causes damage to grasslands and serves as a reference for grassland restoration and management efforts.
豚草（Ambrosia trifida L.）是一种入侵性杂草，其分布范围不断扩大，最近开始在草原上扩散。这一不寻常的事件威胁着全球的草原。本研究旨在评估中国新疆伊犁河谷豚草入侵对草原土壤种子库的影响。我们采用时空替代法，比较并量化了豚草入侵 8 年后和清除后草原土壤种子库群落的变化。结果表明，入侵持续时间决定了豚草是否可能对本地种子库群落构成重大威胁。入侵四年后，本地群落的原位种子库密度显著下降（30.44%），而豚草地上部分的相对盖度达到 83.75%。此外，种子库的物种丰富度显著下降（12.36%），而入侵六年后，豚草的相对盖度达到 100%。入侵八年后，本地群落的种子库密度和物种丰富度分别下降了 83.28%和 39.33%，种子库趋于均匀化。豚草清除后，本地群落的残余种子库密度限制了其再生潜力。尽管经过三年的恢复，本地种子库密度显著增加，但新的生长主要由杂草物种主导，而不是草原生境的特有成分。本研究阐明了豚草对草原造成破坏的过程，为草原恢复和管理工作提供了参考。
