长汀生态恢复区不同混交比例针阔混交林内马尾松种群动态及其驱动机制OA北大核心CSTPCD

[Objective]This study aims to lay a foundation for further understanding the process of subtropical vegetation reconstruction and restoration by analyzing the population dynamics and driving mechanisms of Pinus massoniana,a typical pioneer species in subtropical ecological restoration in China,in coniferous and broad-leaved mixed forests with different mixing ratios.[Method]Based on the survey data of P.massoniana population in four coniferous and broad-leaved mixed forests with different mixing ratios in an ecological restoration area of Changting County,Fujian Province,an integral projection model(IPM)was constructed.Elastic analysis and life table response experiment(LTRE)were used to explore the population dynamics and driving mechanisms of P.massoniana in the mixed forests.[Result]The overall performance of the P.massoniana populations in four coniferous and broad-leaved mixed forests was in a continuous decline state(population growth rate λ<1).However,with the increase of the relative abundance of broad-leaved tree species in the stand,the average survival rate,average reproduction rate and λ of P.massoniana individuals increased first and then decreased.Elastic analysis showed that the survival of individuals was the most important for the growth of P.massoniana population in the mixed forest.The positive growth of small-diameter individuals was beneficial to the development of the population,while the effect of reproduction on population growth was relatively limited.With the increase of the relative abundance of broad-leaved tree species,the most important individuals for the growth of P.massoniana population gradually changed from seedlings to adult trees,and the risk of population maintenance gradually increased.Life table response experiments showed that the difference in individual growth was the main source of the difference in population growth of P.massoniana among different mixed forests.[Conclusion]With the increase in the proportion of mixed broad-leaved trees,the proportion and importance of seedlings and young trees in P.massoniana population continue to decrease,while the proportion and importance of adult trees continue to increase.The differential response of individual life rate at different life history stages drives changes of P.massoniana population dynamics.