Point Pattern Analysis And Niche Characteristics Analysis Of The Main Woodyplants In The South Of Taihang Mountains

The population ecology research is the core direction of ecological research.Niche theory is one of the important theories in the study of population ecology.The general status and status of the species in the community and the whole ecosystem.The point pattern analysis method is a commonly used method for the analysis of population ecology,which is used to study the distribution characteristics of plant populations and the correlation between species.This paper studies the spatial pattern of population distribution,the relationship of 13 main species in the two 1 ha plots in the Taihang Mountains south area combined with niche measurement,point pattern analysis,in order to reveal the community diversity of species coexistence and maintaining mechanism and provide a theoretical basis.In this paper,niche breadth index(B(sw)i),niche similarity ratio index(Cih),niche overlap index(Lih and Lhi)and point pattern analysis are used to analyze the structure,distribution pattern and spatial pattern of species.The results are as follows:Firstly,the size class structure of the main species in the 2 plots mainly is increasing or stable type,this shows that Taihang Mountain south of the secondary forest species update good.The main species in the completely random zero model of spatial distribution pattern is mainly the aggregation distribution,in a heterogeneous Poisson distribution zero model species of the space distribution pattern in the larger scale aggregation degree decreased obviously,in a smaller scale species aggregation degree decreased to a lesser extent,which fully reflect the effect of environmental heterogeneity on the pattern of species.The inter-specific spatial correlation between the 13 main species is mainly expressed as a kind of negative correlation and no significant correlation,the plant community is highly competitive,and the community structure is not stable.The dominant species in the 2 plots are far greater than the other species,so the dominant position is more stable.The effect of shrub species and other species affected close.The main reason is that the competition for the limited light resources between shrubs,shrubs and arboret is fierce.Secondly,in vertical niche research,the same survey method is adopted for the main arbor and shrub species in the plots,which is carried out in different ways,separate research and simultaneous research.When studying simultaneous research,shrub species resource value become smaller,so corresponding changes of shrub species' niche breadth value and niche niche overlap value have occurred,but compared with the results of the separate research,The same living species' niche breadth,niche overlap value size trends didn't change.This indicates that the method of this research is feasible to analyze the ecological niche characteristics of different life types in the same time,and to compare the differences between different types of life.Thirdly,in the vertical niche research,tree species' niche breadth value is generally higher than that of shrub species'.This is because trees have larger individuals,shrubs are relatively short,so tree species occupied more resources position,shrub species only in part of resources.When studying niche overlap,the niche overlap index between species is generally low,and 42.86% of the species pairs in 1 plot is more than 0.1,and 43.33% of the species pairs in 2 plot is more than 0.1.Because the niche breadth of the species,the same living type of species to adapt to the environment and the extent of the use of resources,so the value of its niche overlap.When studying niche similarity,the niche similarity ratio between species is higher.And 52.38% of the species pairs in 1 plot is more than 0.5,53.33% of the species pairs in 2 plot is more than 0.5,which is related to the species' niche breadths and its biological characteristics.Fourthly,in general,the niche overlap value and the niche similarity value between the specie which have larger niche breadth and which is the same living type is larger.On the contrary,the niche overlap value and the niche similarity value between the specie which have narrow niche breadth and which is the different living type is small.Part of the species pairs' niche similarity higher,but niche overlap value is smaller.Mainly because,the demand for natural resources of these species are the same,so between them there is competition,but because of differences in light demand and in communities in different height of resource level in,the resulting in niche differentiation and the overlapping value reduced.Fifthly,When combining ecological niche research and point pattern analysis,we found that: The first,some minor niche breadth species have a higher niche overlap.There are having two reasons,on the one hand is the species have similar biological and ecological habits and consistent demand on the resources and environment,on the other hand is the distribution of species in the plots is patch shape,they have high degree of aggregation in plaques,and the same resource competition.The second,species' niche overlap value and interspecific correlation is not consistent.Part of the same living type species' ecological niche overlap value is higher but the interspecific negative correlation scale is small,which may be due to the competitive environment and resources of the species is more abundant,species mutual adaptation and co-evolution.Part of the same living type species' ecological niche overlap value is lower but the interspecific negative correlation scale is higher,this is because the individual shrub undersized and can not compete light with trees,but the trees and shrubs in the same height and resistance to shade are not strong,so they have greater impact,interspecific negative significant correlation.Therefore,when exploring the relationship between species,it is needed to combine the ecological niche characteristics with the interspecific association.