Characteristics Of Bryophyte Communities And Their Accumulation Of Metals In Karst Bauxite Mining Area

XiuwenXiaoshanba Karst Bauxite deposit belongs to the representative open-pit deposit of the bauxite belt in Central Guizhou.The exploitation and metallurgy activities lead to many environmental problems in mining area.Therefore,there are a certain representative and practical significance to research the characteristics of bryophyte communities and accumulation of metals in Xiaoshanba Karst Bauxite deposit.Investigating Xiaotaba Karst bauxite Deposits in October 2015 and November 2017 respectively,We had collected 255 samples of bryophytes.Results showed that:(1)There were 90 taxa of bryophytes belonging to 35 genera and 15 families,among them,3 taxa of liverworts belonging to 3 genera and 3 family.The Pottiaceae was dominant family,the Brachythecium B.S.G.was dominant genus and the B.ditrichoides Broth.was dominant species.The wefts was the mian life form of bryophytes and there were many single-species communities in mining area.(2)Analysing the community characteristics from different natural succession stages and different habitats.Using the diversity indices to analyse the level of bryophyte diversity.The results showed: the Shannon-Wiener Index,Pielou Index,and Abundance Index all lowest(0.196,0.283,and-1.930,respectively)in the bare rock stage,and highest(3.470,1.281,and 2.342,respectively)in the herbosa-boscage stage along forward succession.In different habitats,the level of bryophyte diversity,the shelve mining area was the highest,the beside road in mining area was the lowest.(3)Analyed the contents of 10 metals(Al,Fe,Mg,Mn,Cr,Zn,Cu,Pb,Ni and As)in bryophytes and their soil substrates by ICP-OES,atomic absorption spectrophotometer and atomic fluorescence spectrometer,the results showed that the average contents of metal elements in soil were higher than soil background in Guizou.(4)Evaluating pollution degree of soil metal in different habitats by Single Pollution Index method.The results showed that all sample sites were contaminated with heavy metals of different degrees,such as heavy metals pollution with Pb et al.(5)Studied on metal accumulation of bryophytes by bioconcentration factor,the results showed that the different bryophyte communities had different metal-enrichment abilities,and the same bryophytes had different abilities to enrich different metal elements.For example,the Cr and Al bioconcentration factors were 3.567 and 0.058,respectively,that meant the P.neesii(C.Muell.)Dozy community accumulated Cr intensely conversely,it accumulated Al poorly.The bioconcentration factors of B.ditrichoides Broth.community and D.coarctata(C.Muell.)Boesch et Lac.community were 2.135 and 0.204,respectively,the former was relatively enriched Mn,while the latter was relatively depleted.(6)For the correlation analysis of metal elements contents in bryophytes,there might be synergistic and antagonistic effects on absorption between elements,and some elements were associated,such as Ni-Al,were significantly positively correlated,and they might have similar or synergistic effects.