Quantitative Ecology Of Bryophyte Community Under Different Revegetation Patterns On The Reclaimed Dumps In Pingshuo Mining Area

In this study,the bryophyte communities under different revegetation patterns on the reclaimed dumps in Pingshuo mining area of China Coal Pingshuo Group Co.,Ltd.located in Shuozhou City,Shanxi Province is taken as the research object.On the basis of the field plot sampling of bryophytes and soil,the quantitative ecology of bryophyte community under different revegetation patterns on the reclaimed dumps in Pingshuo mining area was studied using the methods of microscope identification,quantitative ecology,soil physical-chemical properties and enzyme activity analyses.The relationship between bryophyte community and soil factors under different revegetation patterns was revealed.The dominant bryophytes with drought-barren-resistant and significant soil improvement effect on the harsh habitat of waste dump were screened,in order to provide scientific basis for the ecological restoration of the waste dump and the protection of bryophyte diversity in the mining area.The main research conclusions are as follows:(1)A total of 7 families,17 genera,and 41 species of bryophyte communities were identified in 75 quadrats of 17 plots with bryophytes under different revegetation patterns on the reclaimed dumps in Pingshuo mining area.Among them,the Pottiaceae Hampe and Bryaceae bryophytes accounted for 60.98% and 26.82% of the total number of species respectively.There were 10 genera in the Pottiaceae Hampe,among which the dominant genus was Didymodon Hedw.There were two genera in the Bryaceae,among which the dominant genus was Bryum.The niche breadth of the dominant species Didymodon vinealis was the largest(0.705),and the niche breadths of the Didymodon rigidulus and Fissidens bryoides was greater than 0.4,which indicated that the three bryophytes(7.32% of the total species)had stronger ecological adaptability.The 7 bryophytes with niche breadths ranging from 0.1 to 0.3 accounted for 17.07% of the total species,and the niche breadths of the remaining 31 bryophytes(75.61% of the total species)were less than 0.1,indicating that most bryophytes had narrow ecological amplitude and were sensitive to habitat changes.(2)The 75 quadrats were classified into 11 bryophyte communities by TWINSPAN,namely,? Comm.Didymodon nigrescens,? Comm.D.vinealis,? Comm.D.vinealis+D.cordatus,? Comm.Bryum argenteum+D.cordatus,? Comm.D.rigidulus+Aloina obliquifolia,? Comm.D.rigidulus),? Comm.D.constrictus+Crossidium crassinerve,? Comm.Fissidens bryoides+D.tectoru,? Comm.F.bryoides+D.ditrichoides,? Comm.Podperaea baii+Bryum lonchocaulon and ? Comm.D.gaochenii.The bryophyte communities of ?,?,? and X distributed in the mixed forest had higher species diversity indices.The result of TWINSPAN classification was consistent with that of DCA ordination.The first DCA axis represents a gradient of soil moisture content of bryophyte communities under different revegetation patterns gradually increased from left to right along the first DCA axis,and the second DCA axis represents a gradient of the species numbers of bryophyte communities gradually increase from the top to the bottom along the second DCA axis.The dominant bryophytes in communities IV,?,? and X,which located on the right side of the first DCA axis and below the second DCA axis,were the species of Fissidentaceae and Hypnaceae families,while the remaining 7 communities were dominated by the species of Pottiaceae Hampe family.(3)Among 91 species-pairs of 14 dominant bryophytes,the ratios of positive and negative associations in x2 test,Spearman rank correlations and Pearson correlation were 0.23,0.26 and 0.08,respectively.More than 79% of the species-pairs were not significantly negatively correlated,indicating that the dominant bryophytes were generally not significantly negatively correlated.The niche overlap values of the species-pairs of Podperaea baii-Bryum lonchocaulon,Didymodon vinealis-D.rigidulus,Aloina obliquifolia-D.constrictus / D.nigrescens,and Crossidium crassinerve-Bryum argenteum were higher than that of the others(less than 0.1).(4)The characteristics of soil physical-chemical and enzyme activities of 11 bryophyte communities under different revegetation patterns were as follows: The soil structure,nutrients and trace elements such as zinc,iron,manganese,etc.of community ? was relatively poor.In addation,its soil p H value(8.6)was higher and slightly alkaline,while soil enzyme activity was the lowest.Compared with community IV,except that community ? had lower soil nutrients due to short revegetation years,the soil physical-chemical properties and enzyme activities of most bryophyte communities were significantly improved and their soil improvement effects were more obvious.Under the mixed forest of Pinus tabulaeformis and bryophytes,?-? soil texture is obviously improved,soil p H value is reduced,soil enzyme activity is increased,the available content of soil alkali hydrolyzed nitrogen,available potassium and soil microelements is gradually increased,but the content of soil available phosphorus is low,which indicates that with the growth of plants,the consumption of soil phosphorus is increased,so the fertilization management should be strengthened in the future vegetation restoration process.The soil texture of bryophyte communities ?-? mostly under the mixed forests of Pinus tabulaeformis significantly improved,soil p H decreased,soil enzyme activities increased,soil alkaline nitrogen(AN),nutrients(available K,Cu,Zn,Fe and Mn)gradually increased,but the available phosphorus(AP)was low.The results showed that with the growth of plants,the consumption of soil phosphorus increased,and fertilizer management should be strengthened in the future revegetation process.(5)The communities ?-X dominated by F.bryoides and Podperaea baii were mostly under the mixed forests of Pinus tabulaeformis.The soil fertility of these communities was higher than that of the unreclaimed dumps,and their soil improvement effects were even more significant.With the gradual improvement of soil properties,more and more environmentally sensitive bryophytes began to colonize under different revegetation pattern.It showed that the revegetation had a significant effect on improving the harsh habitat of waste dump in the mining area.And compared with pure forests,mixed forests,especially the mixed forests of P.tabulaeformis,can effectively and quickly ipmorve soil fertility.(6)The first CCA axis reflects the trendency of canopy density,soil moisture and soil texture gradually increased of bryophyte communities under different revegetation patterns from right to left along the first DCA axis,and the second DCA axis,and the second axis reflects the trendency of soil moisture gradually increased while soil p H value decreased of bryophyte communities from the top to the bottom along the second DCA axis.The CCA ordination diagram of quadrats showed that bryophyte communities ?-? and ? mainly affected by soil AP and p H,while communities ?-X mainly affected by soil enzyme activity,organic matter(OM),total nitrogen(TN),available nitrogen(AN),iron(avail-Fe)and manganese(avail-Mn),and soil moisture(WC).The CCA ordination diagram of bryophytes showed that the 41 species were classified into 4 groups.The dominant species of Didymodon with drought-barren-resistance and basophilic characteristics mainly located on the right side of the CCA ordination diagram(group 1 and group 2);the bryophytes on the left side of the CCA ordination diagram were resistant to moisture and drought(groups 3 and 4),including dominant species of F.bryoides,and P.baii,and B.lonchocaulon in communities ?-?,which were sensitive to habitat changes,and had higher requirements for canopy density and soil quality.In summary,the Didymodon and Bryum had a great advantage in the bryophyte communities under different revegetation patterns on the reclaimed dumps in Pingshuo mining area,which had strong ecological adaptability to the harsh habitats of the dump.Soil organic matter,p H value and enzyme activity(alkaline phosphatase and catalase)were the major soil factors affecting the distribution of bryophyte communities on the reclaimed dumps in Pingshuo mining area.There were many kinds of bryophytes under different revegetation patterns with higher canopy densitywhere soil quality improved significantly,D.vinealis,D.rigidulus,B.argenteum,D.cordatus,D.tectoru,D.constrictus and D.gaochenii occupied a dominant position in the communities,which niche widths were greater than 0.08,and they had strong ecological adaptability and significant effect on soil improvement.Among them,the dominant species-pairs of D.cordatus-D.vinealis/D.nigrescens,B.argenteum-D.rigidulus/D.tectoru had positively correlation,and therefore could be used as pioneer and/or dominant bryophytes for mixed with arbor,shrubs and herbaceous plant species for future ecological restoration of coal wate dump in order to accelerate the process of revegetation in mining areas.