摘要
随着放牧利用强度的增加，羊草草地位被的地上现存量减少；放牧利用强度中等以上时草地的地上现存量显著地低于非放牧羊草草地（Ｐ＜０．０５）．与地上部分相比，０～３０ｃｍ土层中根系和羊草根茎的重量对放牧利用强度的反应不敏感。羊草草地某一生境的种类组成、物种多样性和群落丰富度能很好地反映生境放牧压力的历史，从非放牧到过牧的牧压生境系列上，植被的物种多样性和群落丰富度对放牧利用强度表现为偏钟型反应曲线。尽管放牧造成的植被演替是渐进的和连续的，但是，某一具体地段群落状态的转变动某种群落的发生，除与放牧压力、地形和土壤理化性状等生态因子有关外．也带有某种随机性，因而是不确定的和不可预测的。
Abovegroundstanding crops were gradually reduced with the increaseof grazing use in-tensity in Aneurolepidium chinense grassland , Aboveground standing crops of sites suf-fered more severe disturbance than medium grazing use intensity were significantly(P<0. 05)lower than that of no grazing sites (fenced). The effects of root weight of sward and rhyzome weight of Aneurolepidium chinense(0～3 0 cm belowground)to grazing use intensity had the similar trend as aboveground part , but they were relatively less sensible than the latter. Plant composition , species diversity and community richness of one site reflected its history of grazing use intensity in the grassland.Agroup of similar deviated bellshaped response curves were obtaind when the number of species,species diversity and community richness were tested among all five grazing use intensities. Al-though the vegetation succession resulted mainly from grazing was progressiveand con-tinuous,the transition of community states at a certain area was undetermined and un-predicted.The appearance of one state was not only the consequence of the complex ef-fects of aplogical factors(e.g.grazing pressure, geographical position and soil charac-ters),but also a stochastic event at all.
出处
《中国草地》
CSCD
1995年第1期1-5,共5页
Grassland of China
关键词
羊草
草地
放牧
物种多样性
群萍丰富度
Aneurolepidum chinense grassland,grazing use intensity,species di-versity,community richness
