不同放牧强度对鹅绒委陵菜克隆生长特征的影响

在中国科学院海北高寒草甸生态系统定位站,对通过17 a不同放牧强度干扰后金露梅灌丛草甸内鹅绒委陵菜克隆生长特征进行实地调查统计研究.结果显示:长期放牧并增加放牧强度后,植物群落的高度、盖度和草场质量指数下降.随着放牧强度增大,鹅绒委陵菜无性系匍匐茎数目增加,分枝强度加大;基株变矮,逐渐由直立、半直立型变为匍匐状,形态可塑性明显;根长有逐渐增加的趋势;放牧强度对鹅绒委陵菜无性系分株高度、根长和分株叶数影响不显著;间隔子有变短、变粗的趋势,间隔子数目和分株数目有增加的趋势,但影响不显著;轻牧和不牧样地中用于鹅绒委陵菜克隆生长的平均能量投资(分株和匍匐茎的干重及其所占比例)小于重牧样地.表明随放牧强度增大,鹅绒委陵菜无性繁殖能力增强,呈现出典型的生态适应策略.

Effects of Different Grazing Intensities on Growth of Potentilla anserina Clones

Growth characteristics of Potentilla anserina clones grazed at different intensities in 17 years were yield investigated in the Position Station of Alpine and Cold Meadow Ecosystems in Northern Qinghai and statistically analyzed.The results showed that after long-term grazing at increased grazing intensity,the florae declined in their heights coverage and grassland quality.As the grazing intensity increased,P.anserina clones increased their stolon numbers and branching capacities,and their plants become short and gradully transformed from erect and half-erect ones into procumbent ones,presenting a clear plasticity in their morphologies.The grazing intensities did not showed significant influences on the plant heights,root lengths and leaf numbers of the ramets of P.anserina clones,tended to insignificantly make the spacers shorter and thicker and the spacer and ramet numbers increase.The energy inputs in the growth of P.anserina clones(dry wiehgts of the ramets and stolons and their proportions) in the quadrats with light grazing and without grazing were lower than those in the quadrats with heavy grazing.It was shown that as the grazing intensity increased;P.anserina clones increased their asexual reproductive capacities,which presented a typical ecologically adaptive strategy.