民勤绿洲荒漠过渡带人工梭梭种群年龄结构及动态

基于野外样地调查数据,通过分析静态生命表、存活曲线、动态指数等参数,结合时间序列模型,研究了人工梭梭种群年龄结构动态,旨在预测人工梭梭种群演替趋势,为退化人工梭梭种群恢复与重建提供理论依据。结果表明：(1)民勤绿洲荒漠过渡带人工梭梭种群的年龄结构近似于“金字塔”型,幼龄林个体占总物种数的90.1%;(2)人工梭梭种群存活曲线趋近于Deevey-Ⅱ型,为稳定型种群。不同区域人工梭梭种群的第Ⅰ、Ⅱ、Ⅲ龄级个体死亡率和消失率最高;(3)动态量化结果显示人工梭梭种群总体均表现为增长型,对外界干扰敏感性较强;(4)时间序列预测分析表明,在未来2、4个龄级时间后,种群Ⅱ、Ⅳ龄级个体数量大幅度增加,人工梭梭种群发展趋势较好。民勤绿洲荒漠过渡带人工梭梭种群为稳定增长型种群,种群具有一定的自然更新能力。针对该种群幼龄个体死亡率较高的问题,未来建议加强对第Ⅰ、Ⅱ、Ⅲ龄级幼株的精准抚育管理,通过人为辅助措施提高幼苗的保存率,促进人工梭梭林的可持续发展。

Age structure and its dynamics of artificial Haloxylon ammodendron population in Minqin oasis-desert ecotone

Based on the field survey data, through analysis of static life table, survival curve, dynamic index, and other parameters, combined with time series model, the age structure dynamics of artificial H. ammodendron population was studied to predict the succession trend of artificial H. ammodendron population and provide theoretical basis for the restoration and reconstruction of degraded artificial H. ammodendron population. The results showed that:(1) the age structure of the artificial H. ammodendron population in Minqin oasis-desert ecotone was like "pyramid" type, and the young forest individuals accounted for 90.1% of the total species; (2) the survival curve of artificial of H. ammodendron population closed to Deevey-II type, which belongs to stable population. The mortality rate and disappearance rate of the first, second and third-age individuals in different regions were the highest. (3) the results of dynamic quantification showed that the population of artificial Haloxylon ammodendron presented an overall growth pattern and was highly sensitive to the external interference; (4) time series prediction analysis showed that after the next 2 and 4 age classes, the number of individuals of population II and IV increased significantly, and the development trend of artificial H. ammodendron population was better. The artificial H. ammodendron population in Minqin oasis-desert ecotone was a stable growth population, which had certain natural regeneration ability. In view of the high mortality rate of young individuals in this population, it is suggested to strengthen the precise tending management of the first, second and third age plants, improve the survival rate of seedlings through artificial auxiliary measures, and promote the sustainable development of artificial H. ammodendron forest.