Study On Degradation Evolution Process And Restoration Priority Of Maqu Alpine Wetland In Gannan

Maqu alpine wetland in Gannan is located in the eastern edge of the Qinghai-Tibet Plateau.It is a sensitive zone of climate change in China.As an important ecological security barrier area,it plays an important role in the comprehensive management of degraded alpine wetland ecosystem.The impact of wetland degradation on wetland function and biodiversity conservation has become one of the most important ecological problems.In recent years,the area of Maqu alpine wetland has been decreasing and shrinking,which has led to a sharp decrease in water supply to the Yellow River,affecting the biodiversity of the region and the sustainable development of the middle and lower reaches of the Yellow River.Under the increasingly severe situation of ecological protection,the protection and restoration of Maqu alpine wetland is imminent.What is the degradation status of Maqu alpine wetland?How is it repairable and difficult to restore?What temporal and spatial order is used for recovery?These are all important problems that need to be solved urgently in the comprehensive improvement of degraded alpine wetland ecosystem.With the support of GIS and RS technology and guided by landscape ecology,this study analyzed the degradation and evolution process of Maqu alpine wetland in the past 35 years from 1980 to 2015 from the aspects of area degradation and structure degradation,and constructed a diagnostic index system for the restoration of alpine wetland ecosystem from the ecological point of view.Based on the multi-objective theory,the restoration of Maqu alpine wetland was scientifically diagnosed.On this basis,based on the theory of land use change,the wetland landscape evolution function was constructed to analyze the multi-year changes of the high-cold wetland.Taking the administrative township as the evaluation unit,the priority of the restoration of the high-cold wetland in Maqu was analyzed,and the succession of wetland restoration in each subarea was given,which provided theoretical support and decision-making reference for the utilization and restoration of wetland resources in Maqu wetland.The main results of this study are as follows:(1)Degradation and evolution of Maqu alpine wetland.By comparing and analyzing the wetland area changes between 1980-2000 and 2000-2015,it is concluded that the wetland degraded rapidly during the 15 years from 2000 to 2015.It is found that the rate of wetland area reduction after 2000 is significantly higher than that before 2000.The change of wetland area in each town is different.Except Nima town increased slightly,the wetland area in other towns decreased in varying degrees.The main degraded townships are Manzhima,Eura and Awancang,which account for 96.26%of the total area reduction of Maqu alpine wetland.From 1980 to 2000,the landscape distribution of Maqu alpine wetland was slightly concentrated and fragmentation was slightly improved.After 2000,the shape of patches became more complex,the number of patches increased,and landscape fragmentation intensified.Landscape fragmentation and accelerated degradation of alpine wetlands pose serious challenges to wetland restoration.(2)Diagnostic evaluation of repairability of Maqu alpine wetland.A diagnostic evaluation model for repairability of Maqu alpine wetland was established,and a conprehensive diagnostie classification map for repairability of Maqu alpine wetland was obtained.The results show that the density of river network(0.147),soil type(0.133),and relative humidity(0.133)have great influence on wetland repairability.In the study area,the suitable area accounts for 9.29%of the total area.Swampy soil and braided rivers are widely distributed in Manzhima,Zailima,Qihama,Awancang and Hequma farms in Nima Township,so the repairable level is relatively high.These areas should be repaired.(3)Priority evaluation of alpine wetland restoration in Maqu.The function of wetland landscape evolution is constructed.It is found that the large-scale land use change makes only 735 km 2 of the stable wetland,accounting for 68.5%of the existing wetland area and 68.2%of the existing wetland area.Maqu alpine wetland needs wetland restoration urgently.Among the 8 townships requiring restoration of Maqu alpine wetland,there are three three three-level restoration zones(Qihama,Awancang and Manzhuma),two secondary restoration zones(Eurasia and Muxi),and three primary restoration zones(Zazhima,Nima and Eurasiuma).Comprehensive evaluation of repairability diagnosis and restoration priority evaluation,the eastern part of Zailima Township in the three-level recovery area(Q3)and the first-level recovery area(Q1)should be given priority to restoration.(4)Wetland restoration should be adapted to local conditions.Different restoration measures are carried out for different types of wetlands.The eastern part of Manzhima,Qihana and Zazhima townships should focus on the protection of peat marshes.Awancang Township should mainly restore River wetlands.Sporadic lakes in Manzhima Township and Hequma Farm should be mainly restored to Lake wetlands.