摘要
用样带法调查了内蒙古高原4种针茅(StipaL.)的年龄结构,并将其年龄划分为5个阶段:幼苗、幼龄、成年、老龄前期和老龄期。结果表明:幼苗对种群年龄结构和动态有较大的影响,针茅幼苗的存活率通常很低,而成年株丛的存活率较高,株丛的实际寿命很长,老龄株丛在种群中占有较大的比例。4种针茅中大针茅(S.grandisP.Smirn.)和克氏针茅(S.kryloviiRoshev.)的幼苗比例较高,从贝加尔针茅(S.baicalensisRoshev.)群落到小针茅(S.klemenziiRoshev.)群落种群中幼龄和成年株丛比例呈下降的趋势,而老龄株丛比例呈增加的趋势;针茅属植物在株丛水平上的动态主要表现为株丛的破碎与枝条自疏过程,以及株丛生殖枝数量和营养枝生物量的波动。
The age status of four Stipa L. species, S. baicalensis Roshev., S. grandis P. Smirn., S. krylovii Roshev., and S. klemenzii Roshev. in Inner Mongolia plateau was analyzed using a transect sampling method. The ontogeny of Stipa species was divided into five stages: the seedling, juvenile, reproductive, presenile, and senile. Dynamics of the population age spectra were determined mainly by the appearance of new individuals and their death rate. The survival rate of the seedlings was very low while that of the adults was high. The considerable longevity of bunch life allowed the old individuals to accumulate in the population. Both S. grandis and S. krylovii had higher proportion of seedlings than others. The proportion of the juveniles and the reproductives in the population decreased from S. baicalensis community to S. klemenzii community, but the old individuals including the preseniles and the seniles showed a reverse pattern. The aging process occurred in bunch level was characterized by the fragmentation of bunch and the within_bunch_self_thinning of the tillers. The process of within_bunch_self_thinning can be described by power equation Y=aX b . Meanwhile as a response to environment changes especially to the fluctuation of annual precipitation and its seasonal distribution both the numbers of reproductive shoots and vegetative shoot mass within a bunch were variable.
基金
国家自然科学基金!重点基金 (No.3 973 0 110 )
面上基金 (No .3 946 0 0 5 5 )资助项目
关键词
内蒙古高原
针茅
种群
年龄结构
株丛内枝条自疏
Inner Mongolia plateau, Stipa species, Population, Age status, Within_bunch_self_thinning of the tillers
