The Research Of The Environmental Adaptability Of Reaumuria Soongorica Functional Traits And Population In Northwest China

Reaumuria soongorica,is a species of well sand-fixed small shrub of the genus Tamarix,which can adapt to harsh conditions of arid regions because of its scaly leaves.It is widely distributed in Xinjiang,Inner Mongolia,Ningxia,Gansu,Qinghai and some other regions of China.As the major constructive species in desert and desert grassland,R.soongorica plays an important role in maintaining the stability of desert plant community structure and ecosystem,as well as in reducing soil erosion and desertification.However,in the context of climate change and incr easing human activities,how the main functional traits and the population size and distribution range of the species respond to chang es in environmental and climatic factors remains unkown.At present,it has not been universally recognized in the academic circle.Therefore,it is particularly important to study the distribution characteristics of R.soongorica population and the adaptability of functional characteristics of R.soongorica 130 R.soongorica samples were collected from 32 field sampling sites to determine their main functional characteristics here.MaxEnt model was used to analyze the adaptability of R.soongorica in different habitats and the potential distribution areas of the population.The results demonstrated:(1)The traits of R.soongorica leaf in northwest China are greatly affected by site environment.The Results showed that there is a weak latitude pattern in leaf thickness,maximum net photosynthetic rate per unit area and leaf volume of R.soongorica.And there is a weak longitude pattern in specific leaf weight,leaf tissue density and maximum net photosynthetic rate per unit mass.Through the multiple regressio n analysis,we find the leaf thickness are mainly influenced by elevation,mean annual precipitation and soil total phosphorus.The leaf dry mass content are mainly influenced by elevation,annual average temperature and soil total phosphorus.Specific Leaf Weight are mainly influenced by average annual precipitation,soil total phosphorus and mean daily sunshine hours.The leaf volume are mainly influenced by average annual precipitation and soil total phosphorus.And finally the leaf tissue density are m ainly influenced mean daily sunshine hours,annual average precipitation,soil total phosphorus and elevation.(2)There is a trade-off mechanism in the element content distribution of each organ of R.soongorica in Northwest China,and the impact mechanism is different.The results showed that there is a latitude pattern between content of leaf N and P and root C in R.soongorica.There is a longitude pattern of C content in root,which may be caused by hydrothermal condition changes.It shows main influence factors of leaf C content of R.soongorica are soil organic carbon and soil total nitrogen through full subset regression and structural equation model analyses.Leaf nitrogen content are mainly influenced by annual average temperature and elevation,wh ile leaf phosphorus content were annual average temperature,soil organic carbon and elevation,but root carbon content are mean daily sunshine hours,annual average temperature and elevation,and root phosphorus content are mean daily sunshine hours,soil organic carbon and soil total phosphorus,finally stem phosphorus content are soil organic carbon and elevation.(3)Based on the MaxEnt model are predicted the potential distribution area of R.soongorica population under the current climatic conditions and the dominant factors affecting the distribution of R.soongorica population.Under the current climatic conditions,the distribution area of high suitable growth area of R.soongorica in Northwest China is 48.2489×10~4km~2,accounting for 12.2%of the total area of Northwest China,while moderate growth zone distributed 77.7583×10~4km~2,low fitness zone distributed82.4117×10~4km~2,non-suitable distributed 187.0146×10~4km~2.The main climatic variables limiting the distribution of R.soongorica are annual average temperature and precipitation of wettest month,followed by mean temperature of coldest quarter,min temperature of coldest month,mean temperature of warmest quarter and precipitation of warmest quarter.The potential distribution areas of R.soongorica are mainly concentrated in most areas of Ningxia,Hexi Corridor of Gansu,western Haixi Mongolian and Tibetan Autonomous Prefecture of Qinghai,Inner Mongolia and parts of Xinjiang.(4)In the future climate scenario,the distribution area of R.soongorica changes little,but changes in different suitable grades.Except its decrease in the 2050s(RCP2.6)scenario,high suitable area of R.soongorica increases under the other three climatic scenarios.The area increase of high-growth zone is mainly in Altay region of northern Xinjiang,while middle-growth zone is mainly in Alashan League of Inner Mongolia and Haixi Mongolian-Tibetan Autonomous Prefecture of Qinghai.The main limiting factors affecting the distribution of R.soongorica are annual average temperature,precipitation of warmest quartern and precipitation of wettest month.On the whole,the study illustrate the response mode and change trend of R.soongorica functional traits to environmental gradients and climate changes,clarifying the key variables that limit the population size and distribution range of the species,simulating the potential regions and suitability of the species in arid and semi-arid regions in China,in the context of future global climate change s.The study provides an important experimental and theoretical basis for further research of revealing the adaptation mechanism of R.soongorica to drought stress or climate change,and the dynamic change law of their populations,as well as ecological protection and high-quality development in China.