关键词: 红砂种群, 数量动态, 空间分布格局, 动态指数, 谱分析, 兰州

Abstract: Quantity dynamics and spatial distribution patterns of the Reaumuria soongorica populations naturally distributed on the hills in the south and north of Lanzhou were studied.Age structures of the  Reaumuria soongorica populations were worked out by regression of ground diameter and their static life tables were plotted.Through survival analysis and spectral analysis,age structure dynamic indexes of the populations were calculated,thus revealing characteristics of their quantity dynmics.Based on the eight distribution indexes,types of the distribution patterns of the Reaumuria soongorica populations on time and space scales were determined.Results show that the Reaumuria soongorica populations on the two hills were appropriate in population density and crown density with their dynamic indexes being>0 and showing a rising trend.They both demonstrated an obvious periodicity.The populations were dominated with young and middle-aged plants.Mortality in each age class was basically stable,but peaked when the plants were in the transition period from Age Class Ⅱ to Ⅲ.The populations were close to Deevey's Type to to Ⅲ in suvival curve and quite obvious in spatio-temporal heterogeneity.The populations on the sunny slope were distributed in concentration,while on the shady slope they spread evenly.The population distribution patterns of the plants of different development stages varied regularly.Young individuals often gres together in patches,and when they grew older, their aggregation weakened sharply.

Key words: Reaumuria soongorica population, quantity dynamics, spatial distribution pattern, dynamic index, spectrum analysis, Lanzhou