Studies On Taxonomy And Flora Of Brachytheciaceae And Thuidiaceae In Wudalianchi Volcanos, Heilongjiang, China

Brachytheciaceae and Thuidiaceae are two large families belong to pleurocarpous moss. They are also the two families contain more species of the bryophytes in Wudalianchi volcanos. In this study, the species distribution, floristic composition and characteristics of Brachytheciaceae and Thuidiaceae in Wudalianchi volcanos are researched. The main research results are listed as follows:1. A total of 6 genera,21 species of Brachytheciaceae were found in Wudalianchi volcanos. Among them 9 species were new records in Heilongjiang province, which were Brachythecium kuroishicum, Brachythecium glareosum, Brachythecium salebrosum, Brachythecium velutinum, Brachythecium brotheri, Eurhynchium hians, Homalothecium laevisetum, Homalothecium sericeum and Rhynchostegium fauriei. Myuroclada is the genera with single species.The study found that a total of 9 genera,10 species of Thuidiaceae were discovered in Wudalianchi volcanos.3 species were new records in Heilongjiang province:Cyrto-hypnum pygmaeum, Haplocladium angustifolium and Claopodium pellucinerve. There are two genera in Thuidiaceae with a few species, Abietinella and Herpetineuron.2. Floristic analysis of Brachytheciaceae component showed that North Temperate comprised 12 species, which made up 57.14% of the total species. This result suggested its important position in Wudalianchi Volcanos. East Asian elemen (5 species,23.82%), Cosmopolitan elements (2 species,9.52%), Temperate Asia elements (1 species,4.76%) and Endemic to China elements (1 species,4.76%). The Brachytheciaceae in Wudalianchi volcanos area showed distinct characteristics of those in Temperate Zone.The species floristic elements composition of Thuidiaceae in Wudalianchi volcanos was devided into 4 major types:North Temperate elements (6 species, 60.00%), East Asian and North American elements (2 species,20.00%), East Asian elemen (1 species,10.00%) and Pantropical elements (1 species,10.00%). This result showed that the Thuidiaceae in Wudalianchi volcanoes had distinct characteristics of Temperate Zone, and it had some relationship with North America Zone.3. The floristic studies compared Wudalianchi volcanos with other 7 areas in China. The coefficient of similarity of species showed that the Brachytheciaceae in Wudalianchi volcanos had the closest genetic relationship with Qilaotu Mountain, and had the farthest relationship with Guancen Mountain. The Thuidiaceae in Wudalianchi volcanos had the closest genetic relationship with Qilaotu Mountain, and had the farthest relationship with Eastern Tianshan Mountain.4. Study on the species composition of Brachytheciaceae in different eruption ages volcanos showed that the numbers of species arranged from more to less were listed as follows:160-170 thousand years ago (Bijia Mountain, Longmen Mountain and Xiaogu Mountain), comprised 16 species,76.19%> 280-290 years ago (Laohei Mountain and Huoshao Mountain) as well as 340-430 thousand years ago (Jiaodebu Mountain, Wohu Mountain and Gelaqiu Mountain) comprised 11 species, 52.38%> 510-600 thousand years ago (Wei Mountain and Molabu Mountain) comprised 10 species,47.62%> 920 thousand years ago (Yaoquan Mountain), comprised 5 species,23.81%.Study on the species composition of the Thuidiaceae in different eruption ages volcanos showed that the numbers of species arranged from more to less were listed as follows:160-170 thousand years ago (Bijia Mountain, Longmen Mountain and Xiaogu Mountain) and 340-430 thousand years ago (Jiaodebu Mountain, Wohu Mountain and Gelaqiu Mountain), comprised 9 species,90.00%> 280-290 years ago (Laohei Mountain and Huoshao Mountain), comprised 8 species,80.00%> 510-600 thousand years ago (Wei Mountain and Molabu Mountain) comprised 6 species,60.00%> 920 thousand years ago (Yaoquan Mountain), comprised 4 species,40.00%.5. Considering the research area of vegetation composition and water conditions, and combined with the observation of habitat. The habitat of Bryophytes were divided into 5 types:rock habitat, soil habitat, tree habitat, decaying wood habitat and swamp habitat.Compared the species number of the Brachytheciaceae in 5 habitats, we found that the numbers of species in arranged as follows:rock habitat> soil habitat> tree habitat and swamp habitat> decaying wood habitat.Compared the species number of the Thuidiaceae in 5 habitats, we found that the numbers of species in arranged as follows:rock habitat> soil habitat> tree habitat> decaying wood habitat> swamp habitat.