| The deciduous broad-leaved forest of Baiyun Mountain National Nature Reserve has the transitional nature from the north subtropical to the warm temperate zone.The community structure is relatively complex and the species diversity is rich.Studying the community structure characteristics,the spatial pattern of dominant populations and the distribution characteristics of understory light resources in this area will provide important ecological background information for the development of forest species diversity conservation and management in this region.In this study,a comprehensive survey of the secondary forests of Baiyun Mountain was conducted using a combination of fixed monitoring plots(100m×100 m)and temporary plots(20 m ×20 m).Based on the fixed plots,the species composition,diameter structure and spatial distribution pattern were analyzed.The spatial point pattern method was used to analyze the intraspecific relationship between the dominant species,sharp tooth mites and larch;based on the temporary sample,the crown was adopted.The layer analyzer analyzes the differences in light environment between different communities and quantitatively analyzes the effects of light environment on the distribution of understory vegetation species.This study firstly conducted a comprehensive survey of all woody plants with a DBH ?1 cm based on lha plots,and analyzed the species composition,diameter structure,important values,and distribution patterns.The results showed that the plots shared woody plants.There are 43 species of 29 genera,totaling 1165 strains;the diameter structure of the species is close to the inverted "J" shape,and the number of small diameter individuals is mostly;Quercus aliena var.acutiserrata and larch(Larix gmelinii)occupy the community.The main advantages;rare species and occasional species accounted for 13.95%and 46.51%of the total species,respectively;the dominant species in the plot mainly showed aggregate distribution pattern;after the heterogeneous Poisson model excluded the influence of habitat heterogeneity,the species were mainly the performance is randomly distributed.In this study,the pairwise correlation g(r)function and the bivariate g12(r)function are used to map the spatial distribution patterns of the two dominant species,sharp tooth mites and larch,based on the completely stochastic model and the heterogeneous Poisson model.Analysis of intraspecific relationships between species.The results showed that the density restriction affected the spatial distribution pattern of sharp tooth mites and larch in this area.There were obvious intraspecific competitions in the two dominant species.In addition,there was a strong interspecific competition between the two species.The dominant position of cockroaches will continue to be maintained,and the dominant position of larch may change further over time.Based on the secondary forest community of Baiyun Mountain National Forest Park in Henan Province,this study used a canopy analyzer to analyze the differences of light environment among different communities,quantitatively analyzed the effects of light environment on the distribution of understory vegetation species,and explored the light environmental factors and under the forest.The relationship between vegetation species diversity.The results showed that the 28 plots of Baiyun Mountain were divided into 4 groups by cluster analysis.The Pinus armandii community had better light conditions,followed by the Juglans regia community and the Toxicodendron vernicifluum community.The Quercus aliena var.acuteserrata community has relatively poor light conditions;the photo environment factor has an interpretation of 12.98%for shrub species distribution and 14.97%for herbaceous species distribution;The species diversity of shrubs and herbs was significantly positively correlated with the increase of light ratio;with the increase of leaf area index and canopy projection area,the species diversity of shrubs and herbs was significantly negatively correlated.The light environment difference between the secondary forest communities in Baiyun Mountain National Forest Park was studied by this study.The results showed that the light environment played an important role in the spatial distribution of understory species.The better light conditions contributed to the improvement of undergrowth species diversity. |
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