Diversity And Geographical Distribution Of Fissidens In Eastern Subtropical Region, China

The eastern subtropical region of China(Fujian, Zhejiang, Jiangsu and Shanghai) region is vast and topographical complex. There are many different vegetation types. The climate is characterized by its transitional features from subtropical oceanic monsoon climate to temperate humid and semi humid climate. Many nature reserves have been built in the region. Though a lot of documents on bryophyte flora in the region have been published, there still has no detailed and systematic study on Fissidens so far.The species of the genus Fissidens in the studied region were reviewed based on the identification of the recent collections and relevant literatures. The species number and their distribution were obtained. Based on morphological traits for specimen observation and relevant literatures, a clustering dendrogram was produced. Bryophyte flora of the region was also analyzed. The genetic diversity and structure of Fissidens dubius, a species with high morphological variation, were studied based on its ISSR data. Finally, the potential distribution regions of three taxa(F.bryoides var. schmidii, F.ganguleei and F.hyalinus)were predicted using Max Ent. The main results are as follows:1. There are 57 species, 7 varieties and one subspecies of Fissidens were confirmed in China according to our specimen identification and literature checking. In eastern subtropical region including Fujian, Zhejiang, Jiangsu and Shanghai, total of 36 species, 5 varieties were confirmed. Among them, 25 species and 3 varieties were recorded from Fujian including a newly recorded species(Fissidens subangustus), 25 species and 1 variety from Zhejiang with two newly recorded species(Fissidens anomalus and Fissidens capitulatus), 16 species and 1 variety from Jiangsu, 8 species and 2 varieties from Shanghai with a newly recorded species(Fissidens ceylonensis).2. Based on 16 morphological traits, 55 species, 7 varieties and 1 subspecies could be clustered into three groups.3. Ten geographical elements of Fissidens in eastern subtropical region of China were identified. Among all species, 20 belong to tropical element(including pantropical element, Tropical Asia and tropical America disjuncted element, old tropical element, tropical Asia and tropical Ocean disjuncted element, and tropical Asia element), accounting for 55.56% of the total species in the focal region. The geographical element composition of Fissidens revealed that the plants of the genus intended to grow in warm, shady and humid habitats, mainly in tropical and subtropical regions.4. Twelve ISSR primers with stable amplification were selected for Fissiden dubius. By using these primers, 259 bands were amplified from 14 populations of the species, among them, 248 were polymorphic, with a polymorphic percentage of 95.57. The Nei gene diversity index for all the populations was 0.2327, 72.01% genetic variation exited among the different populations. Clustering Analysis on 101 samples based on ISSR data showed that the samples could be divided into six groups: Group 1 included the populations from Wuyanlin, Dashenxianju, Longwantan, Qinliangfong reserve, and Yandangshan, Zhejiang; Group 2 included those from Beishan of Jinhua, Zhejiang; Group 3 includes the populations from Wuyishan and Tianbaoyan, Fujian; Group 4 included Huaping population from Guangxi; Group 5 included Longchi population of Sichuan, and Group 6 included Baisilazi population of Liaoning. Analyses showed that the genetic differentiation among the populations of the species were mainly caused by their geographical difference, while the genetic differentiation within populations might be correlated with their heterogeneous environments.5. Based on the current weather data and the geographical records of F. bryoides var. schmidii, F. ganguleei and F. hyalinus, potential distribution regions of these three species in the focal region were predicted by using MaxEnt and ArcGIS 9.3. Under the current climatic conditions, the potential distribution region of F. bryoides var.schmidii would cover Jiangsu(Yuntaishan, Aishanjiulonggou, Dadongshan, Shengrenwo, Quanshan), Zhejiang(Fengyangshan), Fujian(Huboliao, Daiyunshan, Yunzhongshan); that of F.ganguleei would include Fujian(Laoyingshan, Tengshan, Huboliao, Daiyunshan, Yunzhongshan, Tailaoshan), Zhejiang(Putuoshan, Yandangshan), and for F.hyalinus, its potential distribution regions would cover Jiangsu(Yuntaishan, Aishanjiulonggous, Dadongshan, Shengrenwo, Quanshan, Tieshansi), while the weather of Zhejiang and Fujian were not suitable for F. hyalinus. Though these three species have not been recorded in the surveyed region, we should pay attention to them to see whether they are present or not in this region.