亚热带山地草地退化系列上种群更新研究

从种子库，幼苗和种子雨等方面对亚热带山地草地退化系列上5种植物的种群更新进行了研究，结果表明：（1）引入种多年生黑麦草（Lolium perenne)和白三叶（Trifolium repens)种群在轻度和中度退化条件下能够正常更新，但不能忍受草地进一步的退化；（2）本地种对草地退化的胁迫表现出较强的承受能力。簇生卷耳（Cerastium caespitosum)、箭叶蓼（Polygonum sagittatum)和华蒲公英（Taraxacum sinicum)的种群更新分别在中度、重度和极度退化草地上处于最佳状态；（3）若要防治草地退化，就应当地引入种的种群更新受到抑制时采取有效措施。

Study on regeneration of species in a subtropical pasture undergoing retrogression process

Seed bank,seedling recruitment and seed production of five prevalent species were studied along a degradation series on a subtropical mountain pasture.Results showed that (1).exotic species Trifolium repens and Lolium perenne regenerated themselves successfully at light and moderate degradation sites,but could not tolerate further deterioration of the pasture.(2).native species showed a great resistance to the stress of pasture deterioration. Cerastium caespitosum were predominant in seed bank,seedlings and seed production at moderate and heavy deterioration sites,while Poligonum sagittatum and Taraxacum sinicum were at heavy and extreme deterioration sites,respectively.(3).to control pasture deterioration and retain high level of pasture productivity,proper and effective measures should be implemented as soon as a reduction is detected in regeneration ability of the introduced species.