Diversity And Community Characteristics Of Aquatic Plants In Qaidam Basin

The Qaidam Basin is located in the northern margin of the Tibetan Plateau,the northwest of Qinghai Province,in the Altun Mountains southeast,northeast of Qilian Mountains,southwest of Kunlun Mountains and is surrounded by Burhan Budai mountains.Its unique topography,geomorphology,hydrology and climate characteristics lead to complex habitat conditions in the region,varieties aquatic plants.However,the diversity of aquatic plants in the Qaidam Basin is seldom studied so far.In this paper,we studied the relationship between the diversity of aquatic plants,floristic composition,community characteristics,species diversity and environmental factors:(1)The results of field investigation show that there are about 76 species of aquatic plants in the Qaidam Basin,belonging to the genera of 32 families and 52 genera.In life,the largest number of aquatic plants,belonging to 18 families,32 genera and 51 species;Followed by submerged plants,a total of 10 families,16 genera and 20 species;A total of 3 families,3 genera and 4 species of floating leaved plants;1 families,1 genera and 1 species of floating plants.(2)In the floristic composition,4 families which including 5 species above constitute the main body of the Qaidam Basin,the Cyperaceae is the largest,followed by Gramineae;the whole basin is contained species were less than 10 species,The differentiation of the size of the study area is heavier,less than or equal to two kinds of small genera are morel,a total of 47 genera and 55 species,accounting for 88.46%of total genera,only Potamogeton is more than 5 species.For the distribution types of52 genera of aquatic plants,the Qaidam Basin is divided into 6 distribution types,dominated by the world,the world distributed is a total of 29 genera,which accounted for 57.69%;the pan tropical distribution types are 8 genera,accounting for 15.38%;the north temperate distribution type are 11 genera,accounting for 21.16%;2 genera of East Asia and North American distribution type,accounting for 3.85%;the old world temperate and the Mediterranean region,West Asia to Central Asia were 1 genera,accounted for 1.92% of total genera.(3)Clustering analysis results showed that the aquatic plant community,community less Qaidam Basin large water bodies,most communities are small in water,aquatic plant communities can be divided into 4 formations and 6 associations.The 4 formations were Potamogeton pectinatus Formation,Eleocharis vallcculosa Formation,Triglochin palustre + Polygonum sp.Formation,Phragmites communis Association.And 6 associations were Potamogeton pectinatus Association,Eleocharis valleculosa Association,Triglochin maritima Association,Triglochin palustre Association,Typha sp.+ Potamogeton perfoliatus + Polygonum amphibium Association,Phragmites australis Association.(4)A field survey was carried out in the Qaidam basin to aquatic plant species,the four diversity indices were calculated on the basis of species diversity,the results of the analysis of ? diversity index of different communities showed that the four indices of species diversity showed a consistent trend,But the species richness and species uniformity change range is not as good as Shannon-Wiener index,Simpson index;The diversity index Shannon-Wiener index is significantly correlated with the Simpson index,the correlation coefficient r = 0.737 **,to the extent that these 2indices are consistent,which can well describe the species diversity and community characteristics;significant correlation between diversity index and richness index,evenness index and there was no significant correlation between species richness index,species richness index and the diversity index showed the same trend.PCA analysis of four species diversity indices of 68 samples showed that the Shannon-Wiener index is most affected by the species richness index,while the Simpson index is far from the richness of the species,indicating that the Shannon-Wiener index is more sensitive to rare species.(5)The results of CCA analysis showed that the conductivity,temperature,latitude and the first axis showed a significant positive correlation,the correlation coefficients were 0.4110,0.2369,0.1951,and negatively correlated with longitude;The second order axis was negatively correlated with longitude,latitude,altitude and pH,and the water depth was positively correlated.The salinity of the arrow is shorter,and the correlation between the two sorting axes is not significant,and the correlation with the community is not obvious;Simpson index is highly correlated with conductivity,latitude and temperature,which is significantly correlated with latitude;Shannon-Wiener index is significantly correlated with longitude.(6)Our results showed that the latitudinal variation of the Qaidam Basin has a certain influence on the distribution pattern of aquatic plants.With the increase of latitude,the species diversity shows a decreasing trend.In the aspect of longitude variation,the species diversity was the most abundant in the middle part of the Qaidam basin.