The Floristic Geography Of Lycophytes And Ferns In Three Parallel Rivers Of Yunnan Protected Areas

The three rivers are the Nujiang,Lancang and Jinsha rivers in Yunnan Province,which originated on the Qinghai-Tibet Plateau.The confluence of the three rivers is the short name of the area from Haba Snow Mountain to Dandanglika Mountain,and from Southern Region of Gao Li Gong Nature Reserve to the northern end of Meili Snow Mountain.The specific latitude and longitude range is 98°-100°30' E,and 25°40 '-29° N.Because its particular geographical location and all kinds of natural environment,the region has nurtured an extremely rich biodiversity,which has always attracted the attention of domestic and foreign scholars who study different directions.Based on the rich collection of lycophytes and ferns in(PYU)of Yunnan University,And extensively consulted the network digitized specimens and related documents and materials,this paper use PPG I classification system for the first time,fully compiled list of lycophytes and ferns in Three Parallel Rivers of Yunnan Protected Areas,analysised and discussed species diversity,floristic geography,horizontal and vertical layout,etc.The main results are as follows:1.There are 643 species 113 genera 35 families in Three Parallel Rivers of Yunnan Protected Areas,which is an Special important part of the lycophytes and ferns in China.The lycophytes and ferns are 363 species 95 genera 30 families in Dulong River Basin,402 species 104 genera 34 families in Nujiang River Basin,276 species 54 genera 20 families in Lancang River Basin,and 262 species 52 genera 22 families in Jinshajiang River Basin,respectively.Dryopteridaceae,Polypodiaceae and Athyriaceae of families were the dominant,Dryopteris and Polystichum of genera were the dominant.2.The water content decreased from west to east in Three Parallel Rivers of Yunnan Protected Areas,and the species distributed in different basins have also changed accordingly.The groups of lypteridaceae,Hymenophyllaceae,Lycopodiaceae and Dennstaedtiaceae in the humid and hot environment were well differentiated and developed in Dulong River Basin and Jinsha River Basin.Corresponding Pteridaceae,which can adapt to drought conditions,is well developed in Lancang River Basin and Jinsha River Basin.3.The floristic components of the genera in Three Parallel Rivers of Yunnan Protected Areas are mainly tropical and subtropical,and the proportion of tropical and subtropical genera in each basin are 64 genera in Dulong River Basin,70 genera in Nujiang River Basin,27 genera in Lancang River Basin,and 26 genera in Jinsha River Basin,accounting for 77.11%,78.65%,62.79%,and 65.00% of the total genera in each basin,respectively.The floristic components of the species were mainly East Asia and Chinese endemic,with 277 species in Dulong River Basin,314 species in Nujiang River Basin,228 species in Lancang River Basin and 209 species in Jinsha River Basin,accounting for 76.30%,79.09,84.13% and 81.84% of the total species in each basin,respectively.The results indicate that the origin of lycophytes and ferns in this study area is closely related to the tropical and subtropical flora,but essentially belongs to the East Asian flora.The results of similarity coefficient analysis showed that the relationship between the Dulong River basin and the Nujiang River basin was greater,followed by the Lancang River basin and the Jinsha River basin,and the other two were less.This study supports the previous view that the Nujiang-Lancang River Basin can be used as an important geographical dividing line.There are 161 species Chinese endemic,accounting for 25% of the whole lycophytes and ferns.There are 55 endemic species in Yunnan,8endemic in Dulong River and 12 endemic in Nujiang Prefecture,respectively.4.The analysis of species richness along the altitudinal gradient showed that water content decreased from west to east in Three Parallel Rivers of Yunnan Protected Areas,different vegetation types are distributed in different watersheds,and the diversity of lycophytes and ferns presents a unimodal distribution pattern along the altitude gradient.lycophytes and ferns were the most abundant in the monsoon evergreen broad-leaved forest in Dulong River basin.lycophytes and ferns were the most abundant in monsoon evergreen broad-leaved forest,middle mountain moist evergreen broad-leaved forest,moist evergreen broad-leaved forest in Nujiang River Basin.In the Lancang River Basin,evergreen broad-leaved forest,Deciduous Broad-leaved Forest,coniferous and broadleaved mixed forest and warm coniferous forest distribute alternately,and the abundance of lycophytes and ferns is also high.In the warm coniferous forest of Jinsha River Basin,the abundance of lycophytes and ferns is the highest,which is dominated by Dryopteraceae.