Ecological Water Demand Calculation Of Wetland Based On Sensitive Protection Target

Wetland ecosystem is composed of plants,animals,microorganisms and their dependent environment.Zhalong nature reserve is an important place for red-crowned crane breeding and wintering due to its unique natural climate,hydrological conditions and geographical features.In this study,the red crowned crane and reed were selected as the sensitive protection targets to solve the problems of land shrinking,function weakening and degradation of zhalong wetland.In order to guarantee the ecological health and safety of the wetland and make scientific use of water resources,the ecological water demand of zhalong wetland was studied.Main work contents and research achievements are as follows:?1?According to the typical characteristics of wetland,the connotation of ecological water demand is deeply understood,the definition and calculation method of ecological water demand are analyzed,and then the calculation method system of ecological water demand is put forward according to the specific situation of Zhalong wetland.?2?The Zhalong wetland remote sensing image information collection,using the interpretation and supervised classification by remote sensing and GIS technology,the area of accounting specific component types,analysis of the pattern of land cover,change,transfer matrix,degree of land use change,the study found that reed swamp area increase,swamp area reducing,Zhalong wetland drying trend gradually enhanced.?3?The reed in Zhalong wetland was selected as the research object to investigate the water depth of different sides of zhalong wetland and the biomass indexes of reed plant density,biomass,coverage and plant height.The relationship between the typical biological indexes of the whole life cycle of reed and the water depth response was established by using the gaussian curve,and the appropriate water depth of reed at different life stages was proposed.The research shows that the suitable water depth for the whole life cycle of reed is 40⁸0 cm.?4?According to the relationship curve between water level and lake and swamp,the appropriate water level is determined in combination with the sensitive protection target,and the minimum appropriate area of lake and swamp is determined.Using remote sensing technology and NDVI and MDVI indexes,the historical area change curve of reed marsh was established,and the minimum suitable area of reed marsh was determined by combining with the sensitive index target,then the minimum suitable area of the whole zhalong wetland was proposed,and the appropriate ecological water demand of zhalong wetland was calculated.The minimum suitable area of zhalong wetland lake marsh is 402.97 km^2,and the minimum suitable area of reed marsh is985.20 km².The suitable ecological water demand of zhalong wetland is 525.16×10⁶m³,and the calculated results in this paper are scientific and reliable,which can be used as the basis for habitat protection and optimal allocation of water resources for red-crowned cranes in zhalong wetland.