The Study Of Vascular Plant Diversity And Characteristics Of Plant Communities In Baohua Mountain

Baohua Mountain,which located in the middle of Ningzhen Mountain range of Jurong City,Jiangsu Province,is the provincial Nature Reserve and National Forest Park,as well as the critical area for biodiversity research.In this study,the vascular plant diversity and characteristics of plant communities in Baohua Mountain were investigated by means of sample line and plots methods.On the basis of the investigation,the composition characteristics and nature of plant diversity,the origin and evolution of the flora,the types and usage of plant resources,and characteristics of plant communities were analyzed.The relationship between plant diversity and different types of communities and environmental factors were discussed.The specific results are listed as follows:1.Vascular plants diversity and floristic geographical compositionAccording to field surveys,there were 1003 vascular plant species belonging to 581 genera of 155 families in Baohua Mountain,including 37 pteridophytes from 23 genera of 17 families,19 gymnosperms from 14 genera of 7 families and 947 angiosperms from 544 genera of 131 families.At the family level,19 dominant families(with at least 10 species for each)were identified,accounting for 16.52% and 49.22 % of the total families and genera in this region,respectively.However,there was no dominant genus because most genera consisted of only one or few species.In terms of life form,there were 183 species of trees,166 species of shrubs,28 species of woody vines and 626 species of herbs in Baohua mountain,accounting for 18.25%,16.55%,2.79% and 62.41% of the total species respectively.There were 699 wild vascular species belonging to 412 genera of 122 families in Baohua Mountain,which can be divided into 12 distribution types at the level of families.Among these families,48 ones belong to tropical elements and 22 ones are temperate elements,accounting for39.34% and 18.03% of the total families respectively.The tropical components were dominant,reflecting the tropical elements of the flora origin;The natural flora of vascular plant in Baohua Mountain could be divided into 15 areal-types in generas.Among them,there were 144 and 196 genera with tropical and temperate elements respectively,accounting for 34.47% and 47.57% of the total number of genera.Temperate ingredients showed a certain influence during the recent development and formation,reflecting the transition from subtropical to northern temperate zone.The flora of Baohua Mountain was closely related to the close areas.According to the cluster analysis of environmental factors of climate prediction,the climatic conditions of Baohua Mountain in the future(2050,2070)would be similar to those in southern Yixing(Longchishan +Xiaoheigou).Therefore,the evergreen broad-leaved components of Baohua Mountain and the entire Ningzhen Mountains would increase in the future.Nine rare and endangered plants and fifty-two invasive plants were discovered in BaohuaMountain.The wild plant resources are abundant and mainly distributed in ornamental,medicinal,edible and timber areas.The protection of rare and endangered plants,the control of invasive alien plants and the development and utilization of wild plant resources in this area need more enhancement.2 Characteristics of plant communitiesThe investigation of 56 sample plots which were 20 × 20 m in size showed that the community structure of Baohua Mountain was complex and the above-ground stratification was definite and secondary characteristics.The arbor can be divided into 3 layers.The upper layer was mainly composed of 23 species such as Platycarya strobilacea,Juglans mandshurica,and Quercus acutissima.The middle layer consisted of 45 species mainly including Acer henryi,Cyclobalanopsis glauca and Meliosma oldhamii.The lower layer contained Viburnum dilatatum,Fortunearia sinensis,Diospyros rhombifolia and other 65 species.Except that 103 wild species such as Rosa multiflora,Rubus lambertianus,and Smilax china were investigated,The shrub layer also included some sampling trees.The composition of the herb layer mainly contained 298 species such as Ophiopogon bodinieri,Cyrtomium fortunei,and Oplismenus undulatifolius.Fifty-six plots were divided into five community types by MRT: P.strobilacea +Populus adenopoda Community,Celtis sinensis +Pistacia chinensis Community,Q.acutissima +Quercus variabilis Community,C.glauca +Phoebe sheareri Community and P.sheareri +Phyllostachys heterocycla Community.The DCCA two-dimensional sorting map showed that the altitude and slope are the main environmental factors to affect the plant community types and spatial distributions.Besides,the slope direction and slope position also generated a certain impact on the plant community distribution.The P.strobilacea +P.adenopoda Community and the C.sinensis +P.chinensis Community were distributed in sunny or semi-sunny slopes with low altitude and steep slope.The C.glauca +P.sheareri Community and the P.sheareri +P.heterocycla Community were mainly located in the higher slopes.The Q.acutissima +Q.variabilis Community was widely distributed.In conclusion,the differences of this vertical distribution of the community indicated that the distribution of the existing plant communities were significantly influenced by human intervention.Baohua Mountain is abundant in plant diversity,large families and small genera were dominant.The deciduous broad-leaved forest developed by P.strobilacea +P.adenopoda Community,C.sinensis +P.chinensis Community,Q.acutissima +Q.variabilis Community on the basis of plantation forest can well reflect the human intervention in forest and nature succession trends after intervention.In summary,research of vascular plant diversity and characteristics of plant community in Baohua Mountain can provide a scientific basis for natural vegetation protection,restoration and reconstruction of degraded vegetation in Baohua Mountain and even Ningzhen Mountain Range.