短花针茅草原主要植物种群特征及其资源分配对载畜率的响应

采用随机区组试验方法研究内蒙古高原短花针茅荒漠草原地区主要植物种群特征及生物量资源分配对载畜率的响应,结果表明:植物群落结构在轻度放牧区最佳,不放牧区的植物群落结构优于重度放牧区。2005年降水量(156.8mm)较低,冷蒿、短花针茅和无芒隐子草的盖度、高度及地上现存量显著低于2004年(P<0.05),且随载畜率的增大而降低。从生物量资源分配可看出,冷蒿主要通过营养繁殖来竞争资源,其茎、叶和根的资源分配受载畜率与降水量双重因子的调配,对茎、叶的资源分配在轻牧区较高,且随载畜率增大对根系的资源分配逐渐增大;而短花针茅和无芒隐子草采用相同的生存策略适应载畜率变化,随着载畜率的增加对其根系的资源分配高于茎、叶。

The Response of Characteristics of Dominant Plant Species and Resource Allocation to Stocking Rates in Stipa breviflora Desert Steppe

The experiment was designed with a randomized complete block in the Stipa breviflora desert steppe in 2004～2005 to test the effect of stocking rate on characteristics of three plant species and biomass resource allocation.The results indicated that the coverage,height and aboveground standing biomass of Artemisia frigida,Stipa breviflora and Cleistogenes songorica in 2004 were obviously higher than those in 2005 due to the lower precipitation of 156.8mm,and the coverage,height and aboveground standing biomass decreased with increased stocking rate.Artemisia frigida mainly depended on the vegetative propagation to compete the resources,the allocation of resources to leaf and stem depended on stocking rate and rainfall,the more resources allocation to leaf and stem,the lower stocking rate;the more resources allocation to roots,the higher stocking rate.There was the same strategy to adapt stocking rate for Stipa breviflora and Cleistogenes songorica,the resources allocation to roots was more than that to leaf and stem with increased stocking rate.