Studies On Diversity Of The Seed Plants In Oolong Mountain National Geopark

The Oolong Mountain National Geopark(OMNG)is located in the Northwest of Hunan province,as well as the boundaries of Hunan,Hubei and Chongqing,with special geographical location and diverse landforms.It is a typical representative of the bare karst areas in south China and an important part of 8 richest Chinese endemic genera centers.The unique geological and geomorphologic characteristics of OMNG provide many special habitats for plants possibly resulting in high plant diversity,which have not been systematically studied before.Therefore,it is highly necessary and urgent to conduct a comprehensive survey on plant resources and diversity in OMNG.In this study,the biodiversity of OMNG is investigated based on three-years' field survey,specimen collection and identification,and literature review.The list of seed flora of OMNG is made based on 1256 species of 572 genera in 144 families.Meanwhile,the composition and floristic character of OMNG are analyzed,and the correlation between the studied area and its nearby areas is discussed.In addition,the composition of rare and endangered plants is analyzed,the protection of these species and the utilization of plant resources are discussed.The main conclusions are as follows:1.1256 species(including subspecies and varieties)of 572 genera in 144 families are found in the park,of which 13 species from 8 genera in 5 families are gymnosperms and 1243 species from 564 genera in 139 families are angiosperms.The high proportion of monotypic and rare-species genera shows a high floristic diversity of species composition and reflects the specificity of the park's habitats.2.A new species,Eutrema bulbiferum Y.Xiao & D.K.Tian,and 12 new record species of Hunan province are discovered in OMNG.A new cultivar of Saxifraga,Saxifraga stolonifera 'Hei Kui' is raised based on mutants from OMNG and internationally registered in the “Saxifrage Magazine”.It is the first that new cultivar bred by China in Saxifraga.3.The flora of OMNG shows obvious temperate geographical features and rich tropical elements,and a trend of transition from temperate to tropical.On the family level,the rate of tropical elements(66 families)to temperate elements(38 families)is 1.74,and the percentage(49.04%)of pantropical and its variant ranks the first.On the generic level,the rate of tropical elements(221 genera)to temperate elements(281 genera)is 0.78,and the percentage(20.08%)of north temperate element ranks the first.On the species level,the rate of tropical element(258 species)to temperate element(371 species)is 0.70.4.The flora of OMNG shows a long history of origin and endemic features.In which,23 generas and 606 species are endemic to China.75 species are endemic to Central China,and 9 species are endemic to Wuling Mountains.5.OMNG has distinct limestone floral characteristics,closely correlated with local limestone areas.The integration coefficient of OMNG is not too high,perhaps due to its special karst habitats.The similarity index shows that the flora of this area is most closely related to Dehang.The similarity index between different Karst areas is higher than that of Karst area and non-Karst area.6.The rich species of rare and endangered plants are found in the park,including 59 species of 44 genera in 26 families.In which,44 species are recorded in China Species Red List,including 7 endangered species(EN),29 vulnerable species(VU),8 near threatened species(NT).45 species are recorded in the Wild Plant Directory Mainly Protected by Government(Group one and two).Of these 45 species,4 species are in class I,and 13 species are in class II according the group one;2 species are in class I and 26 species are in class II according the group two.7.The park is rich in plant resources,including 838 species of medicinal plants,371 species of ornamental plants,62 species of oil plants,49 species of forage plants,30 species of fiber plants,21 species of environment protecting plants,14 species of dye plants,13 species of nectariferous plants and 5 species of green manure plants.Many of these plants are very potential for exploitation and utilization.