内蒙古典型草原退化机理的研究

在内蒙古冷蒿小禾草退化草原上，经过６年围栏定量的放牧，分别对９种主要植物种群的形态学特征对放牧的响应进行了研究．结果表明，不同生活型和营养繁殖方式的牧草对放牧率的响应策略是不同的，从而构成了不同放牧率下群落演替的基础．匍匐以不定根行营养繁殖生长或分蘖性强的种群是较适应于重牧的，如冷蒿（Ａｒｔｅｍｉｓｉａｆｒｉｇｉｄａ）和星毛委陵菜（Ｐｏｔｅｎｔｉｌａａｕｃｕｌｉｓ）；以根茎和分蘖行营养繁殖的羊草（Ｌｅｙｍｕｓｃｈｉｎｅｎｓｅ）和冰草（Ａｇｒｏｐｙｒｏｎｃｒｉｓｔａｔｕｍ）及丛生禾草克氏针茅（Ｓｔｉｐａｋｒｙｌｏｖｉ）属宜轻牧植物；以根茎和分蘖行营养繁殖的寸草苔（Ｃａｒｅｘｄｕｒｉｕｓｃｕｌａ）和小丛生禾草糙隐子草（Ｃｌｅｉｓｔｏｇｅｎｅｓｓｑｕａｒｒｏｓａ）属宜中牧植物；而以分枝行营养繁殖的扁蓿豆（Ｍｅｌｉｓｉｔｕｓｒｕｔｈｅｎｉｃａ）和木地肤（Ｋｏｃｈｉａｐｒｏｓｔａｔａ）则宜轻牧．随着放牧率的增大，群落发生明显的变化，小禾草的比例逐渐减少，冷蒿小禾草退化草原最终进一步趋同于星毛委陵菜退化草原；而轻牧可以维持草原现状或使其发生恢复演替，禾草比例增加，即可达到利用式改良的目的

Degradation mechanism of typical grassland in Inner Mongolia.

The experiment was conducted on the degraded grassland in Inner Mongolia dominated by Artemisia frigida and short grasses with given stocking rates for 6 years, to study the morphological responses of 9 major plant populations to grazing. The results show that the grasses with different life types and vegetative reproduction properties differed in responding strategies to stocking rates, which formed the basis for community succession at different stocking rates. The herbage with vegetative reproduction by stolons or of higher tillering, such as Artemisia frigida and Potentilla acaulis , were suitable for heavy grazing. Leymus chinense and Agropyron cristatum which are vegetative reproduction by rhizomes and tillering and Stipa krylovii were suitable for light grazing. Carex duriuscula with vegetative reproduction by rhizomes and tillering and Cleistogenes squarrosa were suitable for medium grazing. Melissitus ruthenica and Kochia prostata with branching reproduction were suitable for light grazing. The community composition changed with increasing stocking rate, and the proportion of short grasses in community gradually decreased. Consequently, the degraded grassland dominated by Artemisia frigida and short grasses ultimately converged to the degraded grassland dominated by Potentilla acaulis. Light grazing could maintain the existing state of grassland, or make it retrograde by increasing the proportion of grasses, which achieved the goal of utility typed improvement.