The Study On The Bryoflora And Its Classification Of Helan Mountain

The Helan Mt. is situated on the border of the Inner Mongolia and Ningxia of China(38°36rN, 105°54'E).The highest peak is known as "Obogda", up to 3556m above sea level. The mountain is 20-40km across from east to west and about 250km from north to south, and about 6000km2 in the area. The Helan Mt. form an important boundary of climate and vegetation in northwest China: the eastern side of the Helan Mt. belongs to steppe climate and steppe vegetation and desert climate and desert vegetation characterize the west resulting in two different biomes. It's an important pivotal point that connects the floras of the Qinghai-Xizang Plateau, the Mongolian Plateau and North China. Hence, it is very important to study the Bryoflora of the Helan Mt.In this paper, by systematically studied 1494 bryophytes specimens and 340 samping, we found that the bryophytes in this area has 30 families, 77 genera and 204 species (including subspecies and varieties), There are 11 species in 9 genera in 7 families belong to Hepaticae, 193 species in 68 genera in 23 families belong to Musci. In these bryophytes, 2 species are new records in China. 132 species in 58 genera in 28 families are recorded in Ningxia firstly, 3 families and 14 genera and 43 species are supplemented to the bryoflora of Helan Mt. there are 6 families which include more than 10 species. In these bryophytes, Pottiaceae includes 17 genera, 67 species; Bryaceae includes 4 genera, 19 species; Hypnaceae includes 6 genera, 17. species; Mniaceae includes 4 genera, 13 species; Grimmiaceae includes 5 genera, 12 species; Amblystegiaceae includes 5 genera, 11 species. The number of 6 families are 20% of all the families, but the percentage of genera of the 6 families is 53.25% and the species percentage is 68.14%. There are 5 families which include 5-9 species, and are 16.67% of the total families, the percentage of genera and species belong to the 5 families are 15.58% and 15.20%. There are 9 families which include 2-4 species, and are 30% of the total families, the percentage of genera and species belong to the 9 families are 18.18% and 11.76%. There are 10 families which include only 1 species,and are 33.33% of the total families, the percentage of genera and species belong to the 10 families are 12.99% and 4.90%. 21 rare and endangered bryophytes are listed according to the rules of IUCN.In order to know more about the bryoflora in this region and its relation between those of the adjacent or related areas including Wulin Mountain of Hebei province, the Southern Great Khingan Mountains, Lu Mountain of Shandong province, the Jinfo Mountain of Sichuan province, Tianshan of Xinjiang and the Altai Mountain, we studied its geographical elements, compared the species abundance, the generic similarity coefficient, and the phytogeographical elements, and we analyzed the floristic spectrum by using the method of Principal Component Analysis (PCA). The conclusions, based on the above research, are as follow: l)The phytogeographical compositions of the bryoflora of Helan Mountain have 105 species of North temperate elements(51.47%), 24 East Asiatic elements(11.76%), 10 East Asian and North American elements(4.90%), 8 old world temperate elements(3.92%), 8 Sino-Himalaya elements(3.92%). This conclusion reflects the temperate zone and East Asiatic characteristics of this region, and this region have genetic relationship with Europe, North America and Himalaya. 2) The bryoflora in this region has the typical characteristics of those in the transition zones, High similarities were found between the bryoflora in this area and those in the Southern Great Khingan Mts, less in the Wulin Mountain, Altai Mountain and Tianshan of Xinjiang, and the least Jinfo Mountain of Sichuan province.We studied the species diversity and ecological distribution of bryophytes in the main forest types of different altitudinal vegetation zones in Helan mountain, and divided the mountain into 4 landscape ecological zones: 1), Hypnum cupressiforme-Pinus tabulaeformis forest zone (1900-2200m),there are 17 families, 31 genera and 55 species of bryophyts;2), Abietinella abietina-Timmia bavarica-Brachythecium-Picea crossifolia—Populus davidiana forest zone (2200-2350m), there are 23 families, 48 genera and 92 species of bryophyts;3), Abietinella abietina-Ditrichumflexicaule-Picea crossifolia forest zone(2350-2900m), there are 27 families, 54 genera and 99 species of bryophyts;4), Didymodon-Grimmia-alpine shrubs and meadows zones(2900-3556m), there are 20 families, 28 genera and 64 species of bryophyts.