内蒙古锡林郭勒草地的草种组分与放牧压的关系研究

通过了采样调查，对内蒙古锡林河流域的放牧草地群落的组成成分，现存生物量，物种多样性等与放牧强度的关系进行了研究。结果表明，距离定居点越远放牧强度越弱，出现了以羊草(Leymus chinensis)和大针茅(Stipa grandis)为优势种的群落。距离定居点越近放牧强度越强，出现了以糙隐子草(Cleistogenes squarrosa)和寸苔草(Carex korshinskyi)为优势种的群溶。单位样方内(1m^2)地上部的现存生物量在强放牧压下的127．3g和较弱放牧压下的303g之间变化。物种多样性的变化则独立于放牧强度差异，在3．13至3．64之间波动。为了判断放牧草地的牧草的生长状态，采用了生长状态质量指数(Stand quality index：SQI)来评价了实验样地群落的生长状态。在定居点的内部，SQI为278，而在离定居点4公里远的样地，指数则变为667。禁牧13年的原退化样地的SQI值从420上升至624。

Relationship between the botanical composition and grazing intensities in Xilingoule grasslands, Inner Mongolia

A study on the botanical composition,abovegroud biomass and stand species diversity was carried out in grasslands under different grazing intensities in the Xilin River basin in Ineer Mongolia.The grasslands near the village were more intensively grazed than the stands away from the village.Lightly grazed stands were basically dominated the intensively grazed stand.The biomass varied from 303 g-m-2 in lightly grazed stand to 127.3 g-m-2 in intensively grazed stand.Stand species diversity indices were 3.13-3.64 irrespective of grazing pressure.The stand wuality under varying pasture coditions was evalusted using a stand quality index(SQI).The SQIs were 278 for an intensively grazed stand and 667 for a lightly grazed stand,which was located 4km away from the village.Thirteen years of enclosure improved the SQI of the grassland from 420 to 624.