不同载畜率下短花针茅荒漠草原物种多度格局

Species abundance pattern in Stipa breviflora desert steppe under different stocking rates

以内蒙古短花针茅(Stipa breviflora)荒漠草原为研究对象,通过野外植被调查,并应用几何级数模型、分割线段模型和重叠生态位模型,分析不同载畜率下的植物群落物种多度格局,旨在研究物种之间的关系和群落格局,揭示过度放牧对荒漠草原植物群落的影响。结果表明:几何级数模型可以较好地拟合短花针茅荒漠草原不同载畜率下植物群落物种多度格局。物种多度格局不随放牧强度的增加而发生变化,但植物频度呈下降趋势,中度放牧和重度放牧使荒漠草原的物种数减少。建群种短花针茅对荒漠草原植物群落格局起关键作用,重度放牧使物种频率降低,但短花针茅频率表现出增加的趋势。

The species abundance pattern of plant community was analyzed under different stocking rates in Inner Mongolia Stipa breviflora desert steppe by using filed investigation and geometric model,segmentation model and niche overlap model,in order to know species interrelation and community pattern,and to reveal the effect of overgrazing on desert steppe community. The results showed that the geometric model well fitted the species abundance pattern of plant community under different stocking rates in S. breviflora desert steppe. With the increasing stocking rate,the species abundance pattern didn＇t change,but the plant frequency decreased. The species numbers were lower in moderate and heavy grazing treatments than in the control and light grazing treatments. The dominant species S. breviflora played a key role in plant community pattern in desert steppe. Heavy grazing decreased the overall community frequency but increased the dominant species frequency.