Plant Diversity And Community Characteristics Of Yellow And Tianmu Mountains In East China

Huangshan and Tianmu Mountains are the main forest resource repositories in East China.They have a variety of forest communities and high species richness.However,there remains some disturbances in tourism development and human economic activities.The protection of plant diversity in these two areas is facing severe challenges.Therefore,it is necessary to study plant diversity and community characteristics in the two areas.Due to the limitations of the study area and the differences in survey methods,there are still some important problems worthy of further study: 1.Status quo of plant diversity in the mountains;2.Differences in community characteristics and structure of vegetation types in different mountains;3.Effects of human disturbance on forest communities.Therefore,we investigated 358 km lines transects and 318 forest plots of 20 m×20 m in Huangshan mountains and Tianmu mountains from 2015 to 2018.The main results are as follows:1.Species composition and floristic characteristics of plant communities in the two mountains.We studied the species composition and floristic composition of plants we investigated from the two mountains.In total,we recorded 1848 species of vascular plants,belonging to 175 families and 760 genera which including 1809 spermatophyte species in 734 genera and 158 families,39 pteridophyte species in 26 genera and 17 families.Meanwhile,Asteraceae and Carex are repectively the family and genera with highest species richness.We recorded 1575 species of vascular plants in Tianmu mountains,belonging to 173 families and 661 genera which including 1504 spermatophyte species in 622 genera and 151 families,73 pteridophyte species in 39 genera and 22 families.Asteraceae and Carex are repectively the family and genera with highest species richness.We also found lots of rare wild plant species including Ginkgo biloba?Parrotia subaequalis?Kirengeshoma palmata and Kirengeshoma palmata.Following the floristic distribution division principle of Wu(2003,2011),weclassified the families and genera into 14 areal types both in Huangshan mountains and Tianmu mountains.Then,we found that both in these two areas,the number of tropic elements is the main elements at the family level and the number of temperate elements is the main elements at the genera level.It is worthy to note that the number of temperate elements at the genera level in Tianmu mountains was larger than Huangshan mountains.2.Species diversity and plant community characteristics in different biodiversity conservation hotspots.We selected Mt.Xitianmu,Mt.Longtangshan,Mt.Yellow and Mt.Guniujiang to figure out the community structure and composition in different forest types of different mountains.We found that Mt.Tianmu had the highest species abundance per unit area.According to the relative proportion of the importance value of evergreen broad-leaved species,deciduous broad-leaved species and coniferous species in each plot,we classified the plots into evergreen broad-leaved forest,evergreen and deciduous broadleaved forest,deciduous broad-leaved forest or coniferous and broad-leaved forest.After that,we investigated dominant species composition,? diversities(ShannonWiener index,Simpson index,Pielou index)and size distribution of four forest types from the four mountains.Important value analyses showed that the majority of plots had different dominant species in the tree layer.Except the shrub layer and the herb layer of coniferous and broad-leaved forest,the two diversity indexes of the other three forest types from Mt.Xitianmu were the highest at each level.The tree layers of Mt.Xitianmu and Mt.Longtangshan quadrats are mainly composed of small-diameter trees with DBH less than 10 cm,while DBH of Mt.Huangshan and Mt.Guniujiang trees is larger(many individuals?20 cm).The average DBH of tree layer in Mt.Huangshan and Mt.Guniujiang decreased along the order of evergreen broad-leaved forest,evergreen and deciduous broad-leaved forest,deciduous broad-leaved forest but rose in coniferous and broad-leaved forest.This pattern may be due to the spatial distribution of Cunninghamia lanceolate.The analysis of the historical changes of species diversity in Tianmu Mountains shows that there are 5 families and some species and genera which have not been investigated in this study.The reasons may be that the investigation scope is still not wide enough and some plant species distributions are limited.3.The impact of economic development and human disturbance on species biodiversity.Based on the degree of human disturbance,we divided the forest plots of Tianmu mountains into natural forest(16 plots),secondary natural forest(25 plots)and plantation(24 plots).We analyzed the species composition,species–area relationship diagram,Jaccard index,important value and ? diversities.There were 244 vascular plants species in 161 genera and 80 families for natural forest,332 species in 208 genera and 101 families for secondary natural forest,and 313 species in 209 genera and 96 families for plantation.The tree layer of natural forest and secondary natural forest were mainly combined with families like Fagaceae and Lauraceae,but in plantation,the dominant species in tree layer were economic species,such as Phyllostachys edulis and Carya cathayensis.The ? diversity indexes in the tree layer of the natural forest were higher than the other two forest types,and Pielou index of the herb layer of the plantation was high.Overall,excessive human disturbance will cause damage to natural vegetation and reduce biodiversity,but moderate human disturbance will have a positive effect on community biodiversity.Based on the results of this study,we put forward some suggestions for the protection of plant diversity in East China,such as adding nature reserves,strengthening the management of nature reserves,increasing publicity and artificial intervention.