新疆野苹果的种群年龄结构与数量动态

Age Composition and Quantitative Dynamic Status of Malus sieversii Population

新疆野苹果是第三纪孑遗物种,目前种群数量和分布面积日益减少,已处于灭绝的边缘。通过对新疆野苹果不同生境种群生命表、存活曲线及种群数量的时间序列预测分析,阐明其种群年龄结构及未来发展趋势。研究结果表明:新疆野苹果种群几乎无1龄级幼体,仅新源县改良场种群存在少量2龄级个体,绝大多数种群优势龄级为4、5龄级,新源县八连种群优势龄级已达6、7级,各种群中老龄个体数量占优势;不同种群的存活曲线大致趋于Deevey-Ⅱ型,各龄级的死亡率相近;由于大部分种群已经处于中龄级,随着时间推移,预计20 a、40 a、60 a后,各种群优势龄级将往后推移,老化现象加剧。应建立新疆野苹果种质资源库,进行人工育苗,对各种群进行补植,促进林分向异龄林发展,并加强人工抚育管理措施,间伐过度密集的灌木、草本,控制病虫害,为幼苗定植创造条件。

Malus sieversii is a Tertiary relic species.With the continuous reduction of population quantity and distribution area,the species is now on the verge of extinction.In this study,the analyses on the life tables,survival curves and time series of M.sieversii were carried out so as to illuminate the age composition and developing trends within the populations.The results showed that there were almost no the seedlings in the first-age class in all the populations,and only a few ones in the second-age class were survival in the population at Agricultural Improvement Station in Xinyuan County,Xinjiang.The dominant age classes in the most populations were the 4th and 5th and even up to 6th and 7th in the Balian population.In short,the mid-and old-aged individuals were dominant in all the populations.The survival curves of M.sieversii populations trended to Deevey-Ⅱtype.It was predicted that the dominant age classes in all the populations would become much more ageing after 20,40 and 60 years.It was suggested to build a genetic resources center of M.sieversii,grow and transplant the seedlings,and strengthen the management to the populations.