Study On Spatial Point Pattern Characteristics Of Coniferous And Broad-leaved Mixed Forests In Northeastern China

Based on the large area permanent monitoring plots in the three different latitudes of Northeast China,we use the species diversity indexes and point pattern analysis method to study the similarities and differences of the communities species diversity and the main tree populations spatial pattern in different regions of the coniferous and broad-leaved mixed forest,in order to systematically reveal the spatial distribution of main tree populations in the coniferous and board-leaved mixed forests and provide a theoretical basis for the ecological restoration and sustainable management of degraded secondary coniferous and broad-leaved mixed forests at the horizontal level,as well as the protection of species diversity.The main study found:(1)The trends of tree species richness index,Shannon-Wiener species diversity index,Hurlbert species diversity index,Pielou evenness index and Simpson ecological dominance index in the three plots are consistent,all are Jiaohe> Liangshui> Changbai Mountain,it can be seen that the species diversity of coniferous and broad-leaved mixed forest in Jiaohe plot is better;this rule is not found in the shrub layer,which may be due to the difference in the number of species and the number of individuals in the three plots.(2)Under the null model of complete spatial randomness,most species significantly deviated from the random distribution on the study scales(0?100m),it shows that the distribution of species is significantly affected by habitat heterogeneity.Under the null model of heterogeneous poisson process,species usually show aggregation distribution at 0?30m,and the aggregation degree decreases as the scale increases and shows uniform distribution or random distribution,and the main pattern type is random distribution;the small-scale aggregation distribution indicates that individuals are more likely to gather around neighboring individuals of the same species,which is beneficial to the population to exert a group effect and form a suitable growth environment.(3)The spatial correlation of different tree species pairs in the three plots is different,but usually at small scales show positive or negative spatial correlation,as the scale increases,they gradually tend to be independent of each other,and a few tree species are independent of each other in all research scales.However,the spatial correlation of different tree and shrub species pairs varies greatly,in the Changbai Mountain plot,positive or negative spatial correlations occur mainly at smaller scales and tend to be independent of each other at larger scales;in the Jiaohe plot,the spatial negative correlation is mainly manifested at smaller scales,and it is mainly independent of each other at larger scales;in the Liangshui plot,the species are basically uncorrelated at the research scales.At the research scales,the interspecific correlation eventually tend to be uncorrelated,indicating that as the scale increases,the environmental and spatial resources required by the interspecific also gradually increase,which reduces the competition between species and is more conducive to different species.Full use of environment and spatial resources.