Study On Aquatic Plant Diversity And Community Characteristics In Hexi Corridor

Hexi corridor area(E 93 ° 20 '~ 104 ° 00',N 37 ° 10 '~ 42 ° 50')is located in the west of the Yellow River in Gansu Province,with low south to north and south mountainous,central plain,northern Gobi Desert,which Shule River,Heihe River and Shiyang River flow.The unique landscape pattern and hydrological characteristics led to that the region is very characteristic of aquatic plant diversity.At present,there are few studies on aquatic plant diversity in Hexi corridor.In this paper,field investigations of aquatic vascular plants were carried out throughout Hexi corridor area to study macrophytes distrubtion pattern and influencing factors.The main conclusions are as follows:(1)The results showed that there were 84 species of aquatic plants in the Hexi Corridor area,belonging to 29 families and 42 genus.Among them,1 family,1 genus and 1 species belong to Pteridophyte,83 species,41 genus and 28 families belong to angiosperm..There are25 species of submerged plants,belonging to 10 families and 10 genus;5 species of floating,belonging to 5 families and 5 genus;2 species of floating-leaved plant,belonging to 2families 2 genus.(2)According to genus distribution areal type,macrophytes in Hexi Corridor can be divided into 7 distribution areal types.Among them,cosmopolitan genus(26)ranked the first,followed by north temperate zone and south temperate zone discontinuous distribution genus(6),north temperate zone genus(4).The seven types of distribution areas can be divided into three categories,namely: the world distribution,tropical nature of the distribution and temperate nature of the distribution.(3)The largest species of aquatic plants in Zhangye City,and the lowest aquatic plant species in Jiayuguan City through the analysis of aquatic plants in the Hexi Corridor five municipal administrative areas.From the perspective of ?-diversity,Zhangye City andJiayuguan City have the highest ?-diversity,while the difference between ?-diversity in Zhangye and Jiuquan is the lowest,indicating that the difference between Zhangye and Jiayuguan is large,and the difference between Zhangye and Jiuquan is very small.(4)Clustering analysis of classification results showed that aquatic plants in Hexi Corridor were divided into 15 communities.There are Ass.Potamogeton perfoliatus,Ass.P.filiformis,Ass.Callitriche palustris-Ranunculus japonicus,Ass.Cyperus globosus,Ass.Phragmites australis+Typha orientalis,Ass.P.distinctus,Ass.Heleocharis valleculosa +Triglochin palustris,Ass.Zannichellia palustris,Ass.P.pectinata+ M.spicatum-P.perfoliatu,Ass.T.orientalis,Ass.C.glomeratus+Polygonum persicaria,Ass.P.australis+P.persicaria,Ass.T.palustris,Ass.M.verticillatum,Ass.S.triangulatus+H.Valleculosa.(5)The results showed that there was a significant negative correlation between water temperature and longitude,and had significant positive correlation with latitude.There was a significant negative correlation between elevation and salinity,and there was a significant positive correlation between salinity and TDS.The correlation analysis of four ?-diversity indices and environmental factors in the main aquatic plant community showed that the correlation between species diversity and environmental factors was not significant.DCCA sequencing results showed that the first sorting axis basically reflected the changes of water temperature in the environmental factors,while the pH value and altitude also had a certain correlation with the axis.The second axis was the basic trend of the longitude,latitude and water temperature of the aquatic plant community.The results of sequencing could reflect the relationship between community diversity and environmental factors.