Phylogenetic Structure And Community Characteristics Of Mixed Broadleaf-conifer Forest Communities Along The Elevation Gradient In Huoshan Mountain In Shanxi Province

The place which is vary the elevation from 1200 m to 2000 m of the Qiliyu region in huoshan mountain was chosed as the sample plot.On the basis of field survey data,the species composition and flora,Communities species diversity,Phylogenetic structure and Phylogenetic diversity,Quantitative classification and ordination,interspecific association were researched by using the related methods of vegetation ecology and quantitative ecology.the results showed as follow:(1)According to the statistics,209 species were recorded in the sample area.Belonging to 159 genera of 60 families.Among of them,2 species of ferns belonging to 2genera and 2 families,1 families,1 genera and 1 species in Bryophytes,and 3 species of gymnosperms belonging to 2 genera and 1 families.There were 56 families,154 genera and 203 species in angiosperms,including dicotyledonous which there were 50 families,130 genera and 173 species and monocotyledon which there were 6 families 24 genera 30 species.The type of distribution was diverse.The 57 families have 10 distribution types and156 genera were divided into 20 distribution types.The northern temperate zone had a large proportion,which was accounted for 34.62% of the total genera.It is indicated that the sample area has obvious temperate characteristics.(2)The species diversity of the whole community and different layers were studied by using H index,? index,S index and J index.From the relationship between species diversity index and altitude gradient indicating that the different trends of the four species diversity indexs in the whole community as well as in every layers.The species diversity index reached the maximum value in the middli-low(1600m)elevation.The reason is thatthis elevation gradient provides a good environment for the growth of species.At the same time it laid the foundation for the emergence of the occasional species.Correlation matrix analysis of four species diversity index were showed that,the H index and the ?,S,H index was significantly positively correlated.The ? and S correlation between was not significant,and with J have significant positive correlation.The S index have significant negative correlation relationship with J.Between H with ? index on the relevance of the highest.(3)Through the correlation research on whole community and different layers between species pool and phylogenetic diversity,the conclusion is drawned that the species had niche conservatism in this area.The phylogenetic diversity had a significant positive correlation with species pool.There are certain phylogenetic structure at all different altitudinal gradient.The phylogenetic structure of community was dispersed at middle-low altitude and clustered at higher altitude.It seems that the competition exclusion might be stronger than habitat filtering in the middle-low altitude.However,competition exclusion might be thinner than habitat filtering in the higher altitude because of the ecological stress might have important impact on this area.With increasing elevation,phylogenetic structure of community from dispersed to clustered showed that when the environment pressure becomes stronger,the competition exclusion tended to be weaker.(4)By using the Ward minimum variance clustering method to the survey of 72 samples were divided into 6 groups.The canonical correspondence analysis(CCA)was chosed to study the community of different altitude gradient and consistent to the results of the Ward classification.The results conform to the actual situation of the field survey at the same time.The explanation of the four environmental factors on the species distribution of the community was 10.56%,and the results presented a extremely significant level.The altitude variation mainly reflected on the CCA1 axis,CCA2 axis mainly reflected from bottom to top the slope getting steeper.We found that the main ecological factors affecting the composition and distribution of species in the community were altitude and slope.(5)In order to explore the correlation between 48 dominant species of the community in different altitude gradient in Huoshan Mountian.The method was used to analyze the interspecific association which combine the variance ratio,?2test,Pearson and Spearman'scorrelation coefficient test.The variance correlation analysis showed that the there were no significant positive correlation relationship between the dominant species and reflected the community to build a harmonious symbiotic among species.The ?2 test showed that 48 pairs were formation of the 1128 species of rooms,478 pairs were positive correlation while 650 pairs were negative correlation,positive and negative correlation ratio was 0.735;Pearson correlation coefficient test,383 pairs of expression were positive correlation,745 pairs of expression were negative correlation,positive and negative correlation ratio was 0.514;Spearman rank correlation coefficient test,450 pairs of expression were positive correlation,678 pairs of expression were negative correlation,positive and negative correlation ratio was0.664.