Study On Population Structure And Quantitative Dynamics Of Main Constructive Species In Gongbu Nature Reserve

In order to analyze the population structure and dynamics of constructive species in typical forest ecosystems in Gongbu Nature Reserve.Taking the populations of Abies georgei var.smithii,Quercus aquifolioides,Picea likiangensis and Pinus densata in Gongbu Nature Reserve as the research objects,the ecological research methods were used to systematically analyze the population structure,quantitative dynamics,spatial distribution pattern and intraspecific and interspecific association.The purpose of this study is to understand the population status and growth law of the main constructive species,predict the future trend and dynamics of population development,and explore the intraspecific and interspecific competition mechanism,so as to provide theoretical basis for the protection,sustainable utilization and future related research of the main constructive species in Gongbu Nature Reserve.The results are as follows :(1)Four main constructive species in Gongbu Nature Reserve were studied by using diameter class structure instead of age structure to draw static life table,survival curve and time series prediction.It was found that the number of seedlings and saplings was large,the height and crown structure were inverted ’ J ’ type,the population belonged to growth type,and the survival curve tended to Deevey-III type.According to the time series prediction analysis,the number of individuals of the four constructive species showed an upward trend with the increase of age class.According to the quantitative analysis of population dynamics,the four constructive species showed a structural dynamic relationship of ’growth ’ as a whole.The risk probability of external disturbance of A.georgei var.smithii population was high.The population growth trend of P.likiangensis population was the largest.The anti-interference ability of P.densata population was strong.The population stability of Q.aquifolioides population was good.The constructive species had sufficient saplings and seedlings,but there were not enough big trees and old trees.(2)Six common index determination methods were used to study the aggregation distribution of A.georgei var.smithii,Q.aquifolioides,P.likiangensis and P.densata populations.The aggregation intensity of Q.aquifolioides population was the strongest,and the aggregation intensity of P.densata population was the weakest.The correlation between small,medium and large trees of A.georgei var.smithii was small,which was conducive to the regeneration and development of the population.The small trees and middle trees of Q.aquifolioides in Sichuan and Yunnan showed a positive correlation,and the small trees and large trees,as well as the middle trees and large trees showed a negative correlation,with obvious competitive relationship.The small,middle and large trees of Nyingchi spruce showed negative correlation on most spatial scales,and there was obvious competitive relationship.There was no significant correlation between small and medium trees,medium and large trees,and there was a negative correlation between small and large trees.(3)The interspecific association of P.likiangensis and A.georgei was mostly irrelevant,indicating that the correlation between the two populations was small and there was a coexistence relationship.The interspecific association between Q.aquifolioides population and Betula platyphylla population was mostly negatively correlated,and there was a competitive relationship.Therefore,to a certain extent,the tending management of seedlings and saplings of A.georgei,Q.aquifolioides,P.likiangensis and P.densata should be strengthened to improve their survival rate and promote population renewal.At the same time,deepen the research content and degree of the main constructive species in Gongbu Nature Reserve,and promote its sustainable use.