Interspecific Association Study In Shrub Layer Of Deciduous Broad-leaved Forest In Worm Temperate Zone

The purpose of analyzing interspecific relationship is to reveal the associations'lawbetween the main plant and other plant species. Interspecific relationship is an organic linkthat formed by interactions between the various populations of species in differentenvironments, it has great significance in determining the degree of spatial association andrevealing the relationship, community ecological species groups and community dynamics,and the relationship between the community and the environment between the two species. Itprovides theoretical basis of returning farmland to forests, guiding forest, reforestation andforest management.Interspecific association is one of the important issues of population ecology, and also ofinterest to research workers in ecology. Back in the early twentieth century, foreignecologists began interspecific association studies, our research in this area starting in theearly eighties. Previous studies have mainly focused on interspecific association level, but itnot enough for a comprehensive understanding of the relationship.The data used in this paper is from the Xiaolongshan Mountain. Weihe River , thetributary of Yellow River, flowing through the area Xiaolongshan 74km, its average waterdensity is 0.585km/km2. Xiaolongshan is a mixed forest classes, dominated by secondaryoak forest and pine, and its forest communities are more complete with rich variety ofcomplex structures. There are 224 families, 945 genera and more than 2700 species in planus,pteridophyte, gymnosperm and angiosperm. The forest is located in the climate ofnorth-south junction of the northern margin of the subtropical sub-humid warm temperatemountain climate, its prevailing climate is continental monsoon climate. Investigating areasare Yushuluobaying forest region, Gaoqiaoxiaoshaying forest region, Baihua forest farm,Dangchuan forest farm and Zhangjiaheihe forest region.With the data of Populus davidiana, Quercus liaotungensis, Acuteserrata and Quercusvariabilis, the overall association was analyzed by VR, the analysis of pairing speciesassociation is using 2×2 list with Yates continuity correction formula, using PC,AC todetermine the association of species pairs, the interspecific correlated measure is usingOchiai index,Dice index, Jaccard index with the correlation analysis of Pearson andSpearman. Finally, four communities of ecological species groups was divided. The resultsshowed that: (1), there had a negative correlation in Populus davidiana and Quercusliaotungensis community interspecific correlation, and a positive correlation in Acuteserrata and Quercus variabilis community interspecific correlation. It means the structure of thePopulus davidiana and Quercus liaotungensis community is unstable and the structure ofAcuteserrata and Quercus variabilis community is stable. (2), Through the community ofoverall association, the Acuteserrata community association is the strongest and the moststable one; the Quercus variabilis community is the second strongest; the overall associationof the Quercus liaotungensis is not strong and community is developing to a more stablestatus; the stability of the aspen community is worst and it is in the primary stage ofcommunity succession. (3), Under the results of inspection and the OI indices, combinedwith the biological and ecological characteristics of species, Populus davidiana, Quercusliaotungensis, Acuteserrata and Quercus variabilis is divided into three ecological speciesgroups, it is a manifestation of micro-environmental characteristics of Shrub layer. Theresults of different communities'association show the character of habitat heterogeneitywithin communities and the interaction with environment.