Community Classification And Geographical Distribution Of Fokienia Hodginsii Forest In Hunan Province

Rare and endangered plants are a special component of national germplasm resources and are related to national ecological security and sustainable development.The conservation of rare and endangered plants has become a focus of the global biodiversity conservation action plan and one of the core elements of biodiversity conservation in China.The study of community ecology of rare and endangered plants can provide a theoretical basis for understanding the endangerment mechanism of specific plants and formulating effective conservation strategies.Fokienia hodginsii belongs to the genus Fokienia in the family Cupressaceae,and its a single species of rare and endangered tree in China,and a national second-class protected wild plant.Due to its remote distribution and precarious habitat,the community characteristics and developmental constraints of Fokienia hodginsii are not yet clear.In this study,the species composition and community structure,cluster classification and distribution,and vegetation-environment relationships of Fujian cypress were systematically studied based on the current geographical distribution of Fujian cypress in Hunan Province.On this basis,we proposed conservation strategies and recommendations suitable for Fujian cypress.The main findings are as follows:(1)There are 164 species of vascular plants in 55 families and 100 genera(including infraspecific ranks)in the Hunan-Fujian Berlin community,of which ferns,gymnosperms and angiosperms account for 7.93%,3.66%and 88.41%of the total number of species respectively;Fagaceae,Lauraceae,Theaceae,Rosaceae and Ericaceae are the dominant families.Fagaceae,Lauraceae,Theaceae,Rosaceae and Ericaceae are the dominant families,with a total of 25.00%and 37.80%of the genera and species in the community.Fujian cypress was the first dominant species with an importance value of 36.59%,which varied significantly among the samples(28.23%-74.84%).Other species in the top ten in importance include Tsuga longibracteata,Castanopsis eyrei,Exbucklandia tonkinensis,Fagus lucida and Pinus kwangtungensis.The plant life cycle is dominated by evergreen trees(39.63%of the total number of species),followed by evergreen shrubs(18.90%)and perennial herbs(17.68%),with a lack of bryophytes.The geographic composition of the community families and genera indicates that the flora of the community is dominated by tropical components,with typical tropical affinities,both strongly tropical-subtropical to temperate transitional nature and ancient,the warm evergreen coniferous forest group of the Fokienia hodginsii forest.(2)The analysis of the tree layer at the DBH and height levels shows that the community is a typical heterogeneous forest with significant vertical structural differentiation and a stable current structure.The distribution of all individuals,populations of cypress and other evergreen and deciduous trees in the community is "unimodal" at breast height,suggesting that all dominant species in the tree layer of the community are in distant decline.The abundance of species and the number of individuals in the community decreased with increasing height class,with bamboo species contributing most to the height class below 10 m.The dominant species in the community were concentrated in the medium diameter class and height,indicating that the dominant species in the community adopted K measures to regulate the survival and development of individuals.General description Fokienia hodginsiithe community is a disclimax community on the steep rocky mountain habitat.(3)Combining the quantitative classification(TWINSPAN and MRT)and expert calibration results,the Fujian Berlin in Hunan Province can be divided into two groups of nine clusters,namely the Fokienia hodginsii-shrub-herb Evergreen Needleleaf Forest(FH-I):Fokienia hodginsii-Blastus pauciflorusDiplopterygium glaucum Association(FH-Ⅰ-1),Fokienia hodginsii-Pleioblastus amarus-Diplopterygium glaucum Association(FH-Ⅰ-2),Fokienia hodginsiiRhododendron latoucheae-Dicranopteris pedata Association r(FH-Ⅱ-3),Fokienia hodginsii-Shrub Evergreen Needleleaf Forest(FH-Ⅱ),Fokienia hodginsii-Pleioblastus amarus Association(FH-Ⅱ-4),Fokienia hodginsiiRhododendron latoucheae Association(FH-Ⅱ-5),Fokienia hodginsii-Yushania basihirsuta Association(FH-Ⅱ-6),Fokienia hodginsii-Rhododendron simiarum Association(FH-Ⅱ-7),Fokienia hodginsii-Rhododendron latoucheae+Rhododendron mariesii Association(FH-Ⅱ-8),Fokienia hodginsii-Rhaphiolepis indica+Rhododendron latoucheae cluster(FH-Ⅱ-9),The composition,structure,habitat and distribution of the flora are described in accordance with the system and specifications for the preparation of the Vegegraphy of China.(4)Environmental factors such as topography,climate and rock exposure significantly influenced the species composition and distribution pattern of the Fujian Berlin community,explaining 42.70%of the variation.Elevation and July precipitation were the most influential topographic and climatic factors on the distribution and species composition of Fujian Berlin communities,while rock exposure was also an important factor.The Fokienia hodginsii-Pleioblastus amarus-Diplopterygium glaucum Association,the Fokienia hodginsii-Blastus pauciflorus-Diplopterygium glaucum Association and the Fokienia hodginsiiPleioblastus amarus Association tend to be low altitude,low rock exposure,warm and humid habitats;the Fokienia hodginsii-Rhododendron simiarum Association tends to be high altitude,high rock exposure,low temperature and dry habitats;the Fokienia hodginsii-Rhododendron latoucheae-Dicranopteris pedata Association,the Fokienia hodginsii-Rhododendron latoucheae Association,the Fokienia hodginsii-Yushania basihirsuta Association,the Fokienia hodginsii-Rhododendron latoucheae+Rhododendron marie si i Association,the Fokienia hodginsii-Rhaphiolepis indica+Rhododendron latoucheae Association tends to be a high altitude,low temperature,dry,low rock exposure habitat.(5)Based on literature and field survey data,we analysed the historical changes in the geographical distribution pattern of Fokienia hodginsii and found that the current distribution range of Fokienia hodginsii community in Hunan is extremely reduced compared with the historical period,and only intermittently distributed in the steep mountainous areas at the altitude of Xiang-Gui,XiangGuangdong and Xiang-Gan borders in the Nanling Mountains and Luoxiao Mountains,the main reason for this distribution pattern is the long-term logging use and its weak water and heat resource competition.Based on a systematic sampling survey,this study combined traditional community science and the compilation and research specifications of the Chinese Vegetation Journal to investigate the community structure,vegetation classification and community-environment relationships of the Fokienia hodginsii community in Hunan Province,and to clarify the key factors influencing the structure and spatial differentiation of the Fujian cypress and the causal factors,the results of which enrich the biological and ecological information of the rare and endangered Fokienia hodginsii community and provide a scientific basis for an in-depth understanding of the endangerment mechanism of this species and The results enrich the biological and ecological information of the rare and endangered cypress and provide a scientific basis for understanding the endangerment mechanism of this species and formulating appropriate conservation strategies.