The Characteristics Of Bryophyte Communities And Their Monitoring Of Heavy Metal Pollution On The Highway In Karst Mountain Area Of Yunnan And Guizhou

With highway construction and operation,there are many environmental problems,especially heavy metal pollution,which will affect the health of the surrounding residents.Bryophyte is sensitive to heavy metal pollution because of its sensitivity to environmental changes,so it is used as a monitor material.Through the collection and identification of 135 specimens collected from the whole 490.6km section of the G60 Highway from Guiyang to Kunming City,the bryophyte community has the following characteristics:(1)a total of 4 families,10 genera and 34 taxa of bryophytes were found in this study,including Pottiaceae(5 genera,13 species),Bryaceae(3 genera,18 taxa),Brachytheciaceae(1 genera,2 taxa)and Mniaceae(1 genera,1 taxon).The species composition of bryophyte communities in the study area is simpler than that in other areas disturbed by human activities,and the species composition is low.(2)the dominant families of the highway are the Pottiaceae and Bryaceae.The dominant genus are the Bryum argenteum Hedw,Didymodon constrictus var.constrictus,Brachymenium exile(Doz.et Molk),Bryum dichotomum Hedw.,Bryum algovicum Sendt.,Bryum funkii Schwaegtr,Bryum caespiticium Hedw,Bryum blindli B.S.G.,Didymodon tetorum(Müll.Hal.).Bryum argenteum Hedw is common species of the research section of the total,which can live well under the harsh environment.(3)the life forms of the study area have Short turfs(50%),High turfs(38.24%),Wefts(5.88%),Cushions(5.88%).Most of them are Short turfs,showing that the living environment is bad beside the highway.(4)it is found that the geographical components of bryophytes in the Karst mountain highway are diversified,including 8 types,namely,Old World Temperate elements(8.82%),North Temperate elements(11.76%),Tropical Asian and Tropical Oceanian elements(5.88%),Tropical Asian ellements(11.76%),Cosmopolitans elements(20.59%),Endemic to China(17.65%),Pantropical elements(8.82%)and East Asian elements(14.71%)Among them,Cosmopolitans elements,Endemic to China and East Asian elements occupy the dominant position.(5)there are 51 species of the complex community,and 10 species of the pure community.The complex community occupies a dominant position.Most of them are lithophyte moss communities,and there are fewer soil communities.The most common species are Bryum argenteum Com.,Didymodon constrictus var.constricta Com.,Bryum argenteum-Brachymenium exile Com.,Bryum argenteum-Didymodon constricta var.constricta Com.,Bryum argenteum-Bryum dichotomum Com..The dominant community is Bryum argenteum com.,and Bryum argenteum is the most widely distributed species in the moss road.By pollution factor method,it was found that heavy metal pollution is in this study.The contents of heavy metals in Bryum argenteum from high to low order Zn> Cu> Cr >Pb> Cd.In the highway section,Zn pollution is the most serious,this section of the road in general is heavy pollution;second is Cu pollution,in general,it belongs to heavy pollution;Cr and Cd are moderate pollution,Pb pollution is low pollution.The pollution degree of heavy metals in road soil was evaluated by single factor pollution assessment,the comprehensive index and potential hazard index.The single factor evaluation method showed that the order of heavy metal pollution in the soil was Zn>Cu>Pb>Cd>Cr,and the heavy metal pollution level of Zn reached heavy pollution.The pollution degree of heavy metal Cr is the lowest,and the over standard rate is 29.63%,which is light pollution,most are in the safety and warning line.Nemero comprehensive index evaluation shows that the whole section is heavily polluted.The potential hazard index showed that the potential ecological hazard coefficient of a single heavy metal was Cd>Cu>Pb>Zn>Cr,in which the heavy metal Cd had the highest contribution to RI,and its ecological hazard was the highest.Combined with the three evaluation methods,heavy metals Zn and Cd were found to be the main pollutants.Overall,the degree of heavy metal pollution in Yunnan is higher than that in Guizhou province.The principal component analysis showed that heavy metals in soil were mainly divided into 2 main components,and heavy metals Zn,Cu,Pb and Cd were derived from traffic pollution,while the heavy metal Cr was derived from the soil parent material.Heavy metal pollutants in bryophytes are mainly divided into 2 main components.Heavy metals Zn,Cu and Pb are derived from traffic pollution,while heavy metal Cr is derived from soil parent material,which is the same as the source of heavy metals in soil.There is a negative correlation between bryophyte diversity and Pb level of heavy metals(p<0.05).The content of heavy metals changed with the distance,and the diversity of bryophyte also changed.This article study bryophyte of the karst mountainous area highway and soil heavy metals research,and further study the floristic characteristics of karst mountain area highway bryophytes and biodiversity protection,to monitor and evaluate the status of heavy metal pollution and damage to karst mountainous area highway to provide basic scientific data of biological monitoring and integrated management.