The Relationship Between Biodiversity And Aboveground Biomass With Soil Properties In North Slope Of Qilian Mountains Meadow Steppe

Qilian mountain is an important ecological barrier of the northwest in China.The meadow steppe has the largest area in Qilian Mountains.There are some regional differences from east to west in the different grassland communities.At present,due to global warming and human activities rising,the dramatic changes to Qilian mountain ecological system.In this paper,three typical sites in the north slope of Qilian Mountains were selected(QS?MS?SS)to study the changes of species community,above ground biomassand biodiversity,soil physical and chemical properties and their correlation of meadow steppe based on the investigation data of two continuous growing seasons from 2013 to 2014,in order to improve its ecological environment,strengthen management and rational utilization of grassland resources and improve the production ability of the grass.The results revealed that:(1)The space characteristics of meadow steppe community show that plant community from east to west vary from Carex spp + Elymus dahuricus to Leymus secalinus + Stipa capillata in the north slope of Qilian mountain(2)The ground biomass variation characteristics of meadow steppe showthat the total above biomasses biomass of every sample sites in 2014 was greater than in 2013,and those for each year were QS<MS<SS in the north slope of Qilian mountain.The biodiversity characteristics of meadow steppe show that the biodiversity index value for the sample sites of SS?MS in 2014 was greater than in 2013,but it was contrary in the sample QS,and the biodiversity index values was QS>MS>SS for each year in the north slope of Qilian mountain.Analysis of the ground biomass and biodiversity correlation show that it was not very obvious between the above ground biomass and biodiversity,while the correlation was significant positive between the Margalef index and the Shannon-Wiener index,and there were not obvious among the Margalef index,the Shannon-Wiener index and the Pielou index.in the north slope of Qilian mountain.(3)Analysis of the soil properties characteristics in soil profile variation incdicate that they have some obvious differences in different samples for soil moisture,soil temperature,soil organic matter,available potassium,and pH value in different growing seasons and the different layers.However,soil alkali-hydrolysable nitrogen and available phosphorus are relatively stable,and the differences are not obvious in the north slope of Qilian mountain.(4)Correlated analysis about the effects of soil properties to the biomass on the ground showed that total biomass above ground with soil temperature,PH value are positive correlation significantly,and it is positive correlation to the effective phosphorus significantly very much,but this is not obvious to soil moisture.The Soil nutrientsmainly affect the properties of the soil to determine the growth of vegetation,which affect the biomass of plants in the north slope of Qilian mountain.The Pielou index and ground temperature have a significant positive correlation and is very significantly negative correlation with ground temperature,The Shannon-Wiener index and organic matter are significantly negative correlation.The Pielou index and soil moisture content are significantly positive correlation in the sample area.The results reveal that the major influential factors of total biomass above ground are soil temperature,effective phosphorus and PH value,biodiversity is influenced by ground temperature,soil moisture and organic matter.