Analysis of environmental factors affecting the distribution of epiphytic bryophyte at Heishiding Nature Reserve,Guangdong Province

We examined the distribution pattern of epiphytic bryophyte communities in different forest types and their relationship with environmental factors based on the study of bryophytes and environmental factors of five 2500 m2 plots at Heishiding Nature Reserve,Guangdong Province,China.Distribution of epiphytic bryophytes showed a vertical gradient along different tree heights:epiphytic bryophyte cover and species richness at the height of 20 cm was much greater than those at 60 cm and higher tree heights;quantitative species composition of the former differed greatly from the latter.Moreover,bryophyte cover and species richness differed greatly among tree species.Tree species were classified into 4 groups according to dentrended correspondence analysis(DCA)and cluster analysis based on epiphytic bryophyte cover.Pinus massoniana,with two dominant epiphytic species of Syrrhopodon(S.prolifer and S.armatus)specific to it,was classified to one group.Quercus chungii,also quite different to other tree species,was classified to one group alone.Other broadleaved trees were classified into two groups according to the forest type that they live in.Trees in needle-broadleaved forest were classified to one group and trees in secondary broadleaved forest to another group.According to the analysis of environmental factors and bark characteristics,for epiphytic bryophytes atmospheric humidity gradient might be one of the major factors that affects the vertical distribution,and bark pH might be an explanation for the difference in the epiphytic cover among tree species,but bark water content has no relation to the distribution pattern.Finally,community structure of epiphytic bryophytes on the same tree species is also affected by forest types.