Community Structure And Population Dynamics Of Tetraena Mongolica In Helan Mountains Nature Reserve

Tetraena mongolica is a unique relict single species in China,and one of the constructive species of desert steppe,fragile,and the disturbance of human activities to its habitat is intensified,which will have a serious impact on the survival of Tetraena mongolica.In this paper,the fauna characteristics,species diversity,population life process and soil physicochemical properties of Tetraena Mongolica,which was distributed in Helan Mountains Nature reserve,while the causes of endangered reasons and protection measures of Tetraena Mongolica were analyzed,and the main conclusions are as follows:There are 33 species of Tetraena mongolica in the tetragonal community,all of which are angiosperms and composed of shrubs and herbs.Tetraena mongolica and Reaumuria soongarica dominate the shrub layer,while Stipaca Pillata and Artemisia xerophytica are the most widely distributed,lush and abundant in the herbaceous layer.The community has temperate character,and the north temperate component is dominant.The physical and chemical properties of soil have great influence on herbaceous vegetation.The physicochemical properties of soil have a greater influence on the population density of Tetraena Mongolica,and seedling is the most important and sensitive stage in the updating process.The population has the characteristics of declining structure in early and middle stage and stable growth structure in late stage.Although the whole of Tetraena Mongolica population is a growth population,the shortage of young individuals,unable to supplement the elderly individuals,shows a trend of change to the decline of the population,difficult to maintain the long-term stability of the population,it is urgent to take protective measures.By analyzing the characteristics of Tetraena mongolica community of different terrains,it can be found that the stability of Tetraena mongolica community on flat ground is the most stable,followed by that on gentle slope and hilly ground.The terrain of flat and sloping land is relatively flat,the habitat conditions are more suitable for the growth of shrub and perennial herbs,and the surface of hilly land is more gravel or sandy,which is more suitable for the growth of annual herbaceous vegetation.The proportion of extremely fine sand and the content of organic matter in the flat soil is higher than that in the gentle slope and hilly land,and the flat soil is suitable for the survival and development of Tetraena Mongolica.In the hilly terrain,due to severe wind erosion,lack of soil and other factors unfavorable to the growth of Tetraena mongolica,the gradual deterioration of the survival environment is an important factor that leads to the survival and development of Tetraena mongolica.