Study On The Relationship Between Water Factors And Plant Diversity Of Wetland In The Middle Reaches Of The Yellow River(Yumenkou-Fenhe Into The Yellow River Mouth)

Based on the survey data of 2013,this paper investigates the water factors of wetland in the middle reaches of the Yellow River(Yumenkou-Fenhe into the Yellow River entrance).Based on the research results of the research group,the relationship between plant phylogenetic diversity and water factor and plant diversity index was studied.The results of the study make up for the deficiency of plant diversity in the region,and further improve the status and data of wetland plant community in the middle reaches of the Yellow River.The main results are as follows:1.The width of the river in the study area is generally increasing from Yumen to downstream.There is no obvious regularity in the distance between the plot and the river bank because of the need to avoid farmland and man-made interference.The minimum groundwater depth is 35.05 cm and the maximum is 158.96 cm.Soil moisture content varied from 0.54% to 5.31%.There was a significant negative correlation between groundwater depth and soil moisture content(p <0.01,r =-0.901),soil moisture content =-0.037 × groundwater depth +5.48.2.On the basis of the APGIII classification system,the phylogenetic diversity of 13 plots was calculated by the phylogenetic software Phylocom.The maximum value of phylogenetic ? diversity index corresponds to plot S1(2289.17),and the minimum corresponds to sample S10(706.894).The results of phylogenetic ? diversity showed that the phylogenetic distance between the S2 and S9 was the highest,and the phylogenetic ?diversity index was the highest(286.31).The phylogenetic distance between the sample S3 and S9 was the lowest(246.36).By calculating the community pedigree structure,wo found that in the plots S1,S9,S12 and S13 the community phylogenetic structure is clustered and there is a tendency to gather between species.There was a significant correlation between phylogenetic diversity,species richness index(Patrick),mean taxonomy difference index(?+)and taxonomic variance index(?+).The results of principal component analysis of all kinds of diversity show that the order of the results of the species diversity of 13 plots is S1>S6>S12>S4>S3>S8>S7>S11>S9>S13>S5>S2>S10.The order of the diversity of the taxonomy is S3>S5>S7>S11>S12>S13>S4>S6>S1>S2>S9>S10>S8.The sequence of functional diversity results is S1>S10>S4>S8>S3>S6>S9>S7>S11>S5>S12>S13>S2.The sequence of pedigree diversity is S1>S12>S3>S9>S5>S4>S6>S13>S2>S11>S7>S8>S10.3.The water factor,which is significantly related to the diversity of wetland plant species,is the groundwater depth and soil moisture content in the middle reaches of the Yellow River(Yumenkou-Fenhe into the Yellow River entrance).The diversity of taxonomy was significantly correlated with river width(p<0.05,r=0.559)and groundwater depth(p<0.05,r=0.593).Only Rao in functional diversity index was significantly positively correlated with soil water content(p<0.05,r=0.555).There was a significant positive correlation between phylogenetic distance(PD)and soil water content(p<0.01,r=0.719),and phylogenetic distance(PD)was negatively correlated with groundwater depth(p<0.05,r=-0.573)There was a significant positive correlation between the nearest taxon index(NTI)and groundwater depth(p<0.05,r=0.661),and the nearest taxon index(NTI)was negatively correlated with soil water content(r=-0.580).