| Baihua Mountain Nature reserve, a national nature reserve in Beijing, features warm-temperate secondary deciduous broad-leaved forest of lithoid hills in North China. We study bryophytes diversity in Baihua Mountain area which reflects largely the characteristics of the bryophytes diversity of lithoid hills in North China. The study on the bryoflora, species diversity of bryophytes community aims to understand the characters of species number, bryoflora and species diversity and community and provide the theoretical bases for the protection of bryophytes diversity in Baihua Mountain.(1) By using morphology and plant comparative anatomy methods, we identify nearly 3000 specimen collected from 2004-2009. The result shows a total of 288 species (including subspecies and varieties) in 106 genera of 38 families were found in Baihua Mountain. The high number of bryophytes species were found at the elevation of 1000-1900m. As to geographical elements, North temperate is dominant (59.6%of the total element) with East-Asian elements the second place (15.2%of the total elements) and Endemic to China elements the third place(10.0% of the total elements), and Tropical elements account for a considerably smaller part(4.4% of the total elements). The analysis of bryoflora in Baihua Mountan is conducted through the method of species richness index and genus coefficient and species coefficient and polar ordination,the results show the position of Mt. Baihua at distribution types of the bryophytes belongs to North China.(2) Four types of bryophytes communities were recognizied:Hydrophytia, Petrophytia, Geophytia and Epixytlophytia. Petrophytia is the dominant one and the Hydrophytia is scarce.(3) The diversity patterns of bryophyte are studied through the analysis of coefficient of similarity and diversity index. The conclusion is as follows:â‘ Ground-floor bryophytes Patrick index is 65. The similarities between Pinus tabulaeformis forest and decideuous broad-leaved forest are the highest, the result was put forward that the Pinus tabulaeformis forest is a key for bryophyte diversity conservation in Mt.Baihua. And Betula platyphylla forest have different species from other forest, so it should be paid attention to in Mt. Baihua. The diversity index of coniferous forest and decideuous broad-leaved forest is higher than that of meadow and Vitex negundo shrub.â‘¡Patrick index of bryophytes on tree is 38. Shannon-Weiner index of bryophytes on Betula platyphylla is the highest, while the Quercus liaotungensis trees boast the highest Patrick index of bryophytes. These index have a high correlation with environment, bark and humidity. The relationships between the diversity index to bryophytes on different trees and the elevation is not remarkable.â‘¢Patrick index of bryophytes on rotten tree is 23, the lower number shows the bryophytes on rotten tree have a correlation with forest age. Periodical study should indicate the development and succession.(4) The niche breadths and overlaps of main species are measured with a series of indices proposed by Levins, Shannon-Wiener and Horn. The results show the most species niche breadth and overlap is lower. The results show the ability is low in utilizing the resources. Hence, the resources are sufficient to all bryophytes in Baihua Mountain.(5) The data were analyzed via the method of Canonical Correspondence Analysis. The relationships between the bryophytes species and the environmental variables were revealed in the biplots of CCA. According to the correlation coefficients of the environmental variables with the first two axes, the environmental variables that influence the distribution of the main species are canopy density, altitude, shrub coverage, base, human disturbance and herb coverage.
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