| Baotianman National Nature Reserve is located in the transitional area from the northern subtropics to the warm temperate.We study bryophytes diversity in Baotianman area which reflects largely the characteristics of the bryophyte diversity of the transitional area from the northern subtropics to the warm temperate.In this paper,a 1 hm2(100 × 100 m)plot of 25 hm2 dynamics plot in the Baotianman National Nature Reserve was used as the study area.The study on bryophyte species composition,a diversity of bryophytes and its relationship with environment factors(topographic factors,woody plant community characteristics and canopy light factors),P diversity of bryophytes and its relationship with distance and environmental differences,relationship between bryophyte distribution and environmental factors,the interspecific association of bryophytes aim to understand the characteristics of species number,species diversity of bryophytes and provide the theoretical bases for the protection of bryophytes diversity in Baotianman.The main findings are as follows:1.By using morphology methods,we identify the 830 specimens were collected.The result shows 87 species of Mosses in 47 genera of 20 families and 12 species of Liverworts in 11 genera of 10 families were found in Baotianman 1 hm2 plot.The bryophyte richness of the four substrates from high to low is stone,trunk,soil,and rotten wood,and the Patrick richness values were 78,61,54,and 33,respectively.There are significant differences in the bryophyte composition between different substrates.The number of common bryophytes between stone and soil is the highest,with 46 species.The number of common bryophytes between soil and rotten wood is the least,only 46 species.The number of common bryophytes among the four substrates is 19,accounting for 19.19%of the total number of bryophyte species.Calculation of Bray-Curtis dissimilarity coefficients between substrates based on the abundance of bryophytes.The Bray-Curtis dissimilarity coefficient between stone and soil is the lowest,at only 0.359.The Bray-Curtis dissimilarity coefficient between stone and rotten wood is the highest,at 0.591.Different substrates bryophyte community communities are dominated by different bryophytes.The dominant species of the stone are Brachythecium populeum and Plagiomnium vesicatum.The dominant species of the soil are Atrichum crispulum,Plagiomnium vesicatum and Brachythecium populeum.The dominant species of the trunk are Herpetineuron toccoae and Pylaisiadelpha yokohamae.The dominant species of the rotten wood is Pylaisiadelpha yokohamae,which important value reaches 42.07.2.Based on 10 × 10 m squares,the number of squares with bryophytes on stone soil trunk and rotten wood substrates are 92,56,95,and 57,respectively.The Kruskal-Wallis rank sum test reveals significant differences in the a diversity of bryophytes among the four substrates at the square level.The a diversity of bryophytes on the four substrates from high to low is stone,trunk,soil,and rotten wood.Spearman correlation analysis was carried out on a diversity of bryophytes and topographic factors,woody plant community characteristics and canopy light factors.The a diversity of bryophytes on the stone is only related to the slope(P<0.1).There is significantly correlation between the a diversity of bryophytes on the soil and woody plant community characteristics(woody plant richness,woody plant diversity,woody plant Evenness and stand density)(P<0.05).The ? diversity of bryophytes on the soil extremely significantly correlated with the elevation and aspect(P<0.01).The positive correlation between a diversity of bryophytes on the trunk and stand density reaches extremely significantly level(P<0.01),and the correlation with elevation reaches a significant level(P<0.05).There is no significant correlation between the a diversity of bryophytes on the rotten wood substrate and all environmental factors.The canopy light factors(canopy scattering radiation,canopy direct radiation,canopy coverage,and leaf area index)had no significant effect on the a diversity of bryophytes.3.Based on 10 x 10 m squares,unlike the a diversity of bryophytes,the substrate with the highest ? diversity of bryophytes is soil,followed by stone and trunk,while on the rotten wood has the lowest ? diversity of bryophytes with relatively large variance.The ? diversity of bryophytes on the stone and soil are extremely significantly correlation with the distance between the squares,while the ? diversity of bryophytes on the trunk is not significantly correlation with the distance between the squares.The similarity relationship between the composition of bryophytes in each squares ware analyzed by non-metric multidimensional scaling(NMDS),and the correlation between NMDS axis and environmental factors was tested by Spearman correlation analysis.The ? diversity of bryophytes on the stone is extremely significantly correlation with elevation,aspect,woody plant diversity,canopy scattering radiation,canopy coverage and leaf area index(P<0.01).The ? diversity of bryophytes on the soil is extremely significantly correlation with aspect,woody plant richness,woody plant diversity,stand density and leaf area index(P<0.01).The ? diversity of bryophytes on the trunk is extremely significantly correlation with aspect,convexity,woody plant richness,woody plant diversity,woody plant evenness,stand density and leaf area index(P<0.01).4.Based on 10 × 10 m squares,the relationship between the distribution of bryophytes among four substrates and environmental factors was studied by Redundancy Analysis(RDA).Environmental factors explained 16.76%in the distribution of bryophytes species on the stone.Aspect and leaf area index extremely significant affect the distribution of bryophytes on the stone(P<0.01).The effect of aspect on the distribution of bryophytes on the stone exceeds other environmental factors.Environmental factors explained 20.53%in the distribution of bryophytes species on the soil.Aspect and woody plant evenness extremely significant affect the distribution of bryophytes on the soil(P<0.01).The effect of woody plant evenness on the distribution of bryophytes on the soil exceeds other environmental factors.Environmental factors explained 7.49%in the distribution of bryophytes species on the trunk.Aspect and woody plant diversity extremely significant affect the distribution of bryophytes on the trunk(P<0.01).The effect of woody plant diversity on the distribution of bryophytes on the trunk exceeds other environmental factors.Overall,the distribution of bryophytes on the soil is more susceptible to environmental factors.the distribution of bryophytes on the trunk is not sensitive to environmental changes.The influence factors of the distribution of bryophytes on different substrate are very different.Aspect has a significant effect on the distribution of bryophytes on three substrates.Study on epiphytic specificity of bryophytes on trunk using Detrended Correspondence Analysis(DCA).The correlation between bryophyte species and host tree species is not obvious.It was found that only Hynaceae connexum was closely associated with Tilia oliveri,and Haplocladium angustifolium showed some correlation with Meliosma veitchiorum and Tilia paucicostata.In addition,other bryophyte species and host tree species are scattered and have a low specificity.5.Based on 830 bryophyte specimens,there is 40.00%of the species pairs that are being a positive association in the rock,of which 5.79%are significantly positive association.35.79%of the species pairs that are being a positive association in the soil,of which 5.26%are significantly positive association.50.52%of the species pairs that are being a positive association in the trunk,of which 13.68%are significantly positive association.39.47%of the species pairs that are being a positive association in the rotten wood,of which 8.42%are significantly positive association.On the whole,bryophyte species have strong independence. |
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