放牧对天山北坡中段草原群落结构和功能群生产力的影响

通过对天山北坡中段典型羊茅草原的动态监测，分析了放牧对草原群落结构和功能群生产力的影响。结果表明：放牧不能改变草原植物生活型功能群的组成结构，且多年生禾草占据主导地位，放牧与不放牧条件下所占比重依次为30．74％～44．999，5、30．819／6～35．71％；中度放牧能够增加草原植物种数，但不能改变羊茅、针茅、草原苔草的优势地位，其优势度分别为11．64％～19．40％，11．05％～19．70％和11．65％～23．79％；植物生活型功能群组成中，半灌木、灌木与多年生禾草、杂类草，多年生豆科草与杂类草间植物量显著正相关，生态互补效应显著。

Effects of grazing on structure and productivity of functional group of steppe communities in middle section on northern slope of Tianshan Mountains

By dynamic measuring, the community structure and functional group productivity of Festuca ovina steppe in the middle section on northward slope of Tianshan Mountains were studied. The results show that the structure of life forms and functional group in F. ovina steppe community were not changed,and perennial grasses with high quality occupied predominantly under grazing conditions. They were ranging separately at 30.74%-44.99% and 30.81%-35. 71% under grazing and no grazing. Moderate grazing could increase the number of plant species in community, but the dominating status of F. ovina, Stipa capillat and Carex liparocarpos had not been changed with their dominances ranging as 11.64%-19.40%, 11.05%-19.70% and 11. 65%-23.79 % respectively. In the components of functional group of life form,positive correlations of biomass existed obviously among shrubs and half shrubs, perennial grasses, forbs, perennial legumina, grasses and forbs, and the ecological compensation effects were significant.