| Interspecific association is a form of correlation among populations,and also an important quantity and structural indicator of community characteristics.The study of interspecific association is of great significance to correctly understand the structure,function,composition and dynamics of plant communities,which can provide theoretical basis for vegetation restoration and species diversity protection.Based on variance ratio,?~2-test and correlation degree(OI index,association coefficient and point correlation coefficient),this research compared the interspecific association between the Quercusalioena var.acuteserrate community,Pinus tabulaeformis community,Pinus armandii community along with Platycladus orientalis community in the the Bao Ji-Tian Shui Expressway(here in after referred to as the Baotian Expressway)road area and the Xiaolongshan forest area.The results showed that:(1)The road area and the Xiaolongshan forest area of tree layer,shrub layer and herb layer showed positive association,and only individual communities showed a negative correlation.The positive association indicates the coordination between the community and its environment.The road area overall connectivity is lower than that forest area counterpart,showing that the stability of the road area is lower,and that plant communities in the road area has been,to some extent,damaged.(2)The species relevance in the road area was lower than that in the forest area among which with the Pinus armandii community of tree layer,the Platycladus orientalis community of herb layer being higher.It shows that the road area stability is lower than that in the forest area.The four communities of tree layer showed positive association between the road area and the Xiaolongshan forest area,and only Pinus armandii community showed negative association with exception of Platycladus orientalis community in road area;The four communities of shrub layer showed negative association between the road area and the Xiaolongshan forest area,while Quercusalioena var.acuteserrate community and Pinus armandii community road area showed positive association with exception of Platycladus orientalis community in road area;The four communities of herb layer showed negative association between the road area and the Xiaolongshan forest area,and only the Platycladus orientalis community were all positively related species both in the road area and the forest area.(3)The degree of positive correlation in four communities was lower than that in forest areas,while the negative correlation degree was higher in forest areas.Only some communities were different.The Pinus armandii community was positively related to forest area,and negative correlation was lower than that in forest area.The independence degree of Pinus tabulaeformis were higher in the tree layer between road area and forest area.The positive and negative association degree of Platycladus orientalis community were higher in the tree layer between road area and forest area with exception of Platycladus orientalis community in road area;The positive and negative association degree of Platycladus orientalis community were higher in the shrub layer between road area and forest area with exception of Platycladus orientalis community in road area;The positive and negative correlation intensities of herb layer in Pinus armandii communitiy were lower than those in forest area.The positive and negative correlation intensities of Platycladus orientalis community were higher than those in forest area. |
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