Functional And Phylogenetic Diversity Of Shrubs Under Two Typical Mixed Forests In Zijin Mountain

In order to clarify the formation and growth characteristics of shrubs under two typical mixed forests in Zijin Mountain,through the acquisition of functional traits data and the construction of phylogenetic trees,shrubs under Pinus massoniana and Liquidambar formosana coniferous and broadleaved mixed forest and Aphananthe aspera and Celtis sinensis broadleaved mixed forest in Zijin Mountain was analyzed by mainly using correlation analysis,functional diversity index,phylogenetic diversity index,etc.The results showed that?1?Many function traits were related to each other and had a stronger promoting effect on the growth of shrub vegetation.The leaf thickness?LT?had a significant negative correlation with the specific leaf area?SLA??p<0.05?.The Leaf area?LA?had a very significant positive correlation with the leaf fresh weight?LFW?and the leaf dry weight?LDW??p<0.0001?.The correlation between physiological functional traits was simpler than that of physical functional traits.The leaf phosphorus content?LPC?was significantly positively correlated with the leaf nitrogen content?LNC??p<0.0001?.The Leaf carbon content?LCC?was significantly positively correlated with the leaf hydrogen content?LHC??p<0.001?.The relationship between physical and physiological functional traits was diverse and complex.The specific leaf area?SLA?had a very significant positive correlation with the leaf phosphorus content?LPC?and the leaf nitrogen content?LNC??p<0.01?.In addition,there was no significant correlation between leaf carbon content?LCC?and physical functional traits.?2?The changes of characteristics of functional traits of shrubs under two typical mixed forests were significantly different,and the overall diversity of functional traits was also significant.The functional trait distance index?FAD?of shrubs under Pinus massoniana and Liquidambar formosana coniferous and broadleaved mixed forest was higher,while the functional evenness index(FE_ve)and Rao quantitive index?FD_Q?were higher under Aphananthe aspera and Celtis sinensis broadleaved mixed forest.It indicated that the difference of forest types has significant effects on various functional traits of shrub layer vegetation.So the shrub layer of different forest types showed different growth characteristics in order to adapt to the environmental differences of forest types.?3?The phylogenetic characteristics of shrubs under two typical mixed forests differed significantly.There were many phylogenetic branches of shrubs under Pinus massoniana and Liquidambar formosana coniferous and broadleaved mixed forest while its structure of phylogenetic tree was more complex and the phylogenetic diversity index was relatively high.The most significant difference was that the phylogenetic structure of shrubs under Pinus massoniana and Liquidambar formosana coniferous and broadleaved mixed forest was aggregative,whereas the phylogenetic structure of shrubs under Aphananthe aspera and Celtis sinensis broadleaved mixed forest was discrete.It indicated that the difference of forest types has a significant impact on the phylogeny of shrub vegetation.The shrub layer of different forest types showed different historical evolution characteristics in order to adapt to the environmental differences of forest types.According to the comprehensive analysis,the difference under two typical mixed forests in Zijin Mountain was due to the different pattern of tree species combination at the initial stage of secondary restoration.It led to the difference of environmental factors such as light,temperature and nutrient under forests,and then affected the formation and growth of shrubs under forests.So there was a great difference in functional traits and phylogenetic characteristics.Therefore,the different succession stages,environmental factors,and human disturbance under different typical forests should be considered comprehensively during the construction of understory vegetation in urban forest in future.