Distribution Characteristics And Ecological Response Of Carex Tussock To Water Level In Typical Wetlands,Northeast China

As a typical wetland vegetation,Carex tussock is widely distributed in marshes,Northeast China.In recent years,the change of climate and the disturbance of human activities have caused the decreasing of Carex tussock.In this paper,geographical distribution of Carex tussock in the typical wetlands was studied by field investigation.Combined with the basic geomorphic types in Northeast China,the Carex tussock was divided into different areas.The distribution pattern and community characteristics of Carex tussock under different microtopography were expounded to reveal spatial distribution characteristics of Carex tussock.By researching on the ecological response of Carex tussock to water level gradient,the suitable ecological amplitude of Carex tussock were clarified,which provided technical support and scientific basis for the protection and restoration of Carex tussock.(1)Spatial distribution characteristics of Carex tussock in wetlandsCarex tussock is mainly distributed in five areas in northeastern China: Greater Khingan Range and its piedmont plain,the Lesser Xingan Range and its piedmont plain,Sangjiang Plain,Songnen Plain,ChangbaiMountain.The distribution pattern of Carex tussock mainly include five types: ring distribution,banding distribution,crescent distribution,planar distribution and patchy distribution.Community of Carex tussock rich in species composition and structure is complex,the dominant species is carex.There are some differences of Carex tussock under different microtopography.The average density is the highest in planar depression,which is 15 cluster/9 m2.the average distance is more than 70 cm in saucer depression and crescent depression.There are no significant differences in the height,diameter and perimeter of Carex tussock.(2)Ecological response of Carex tussock to water level in wetlandsThe variation of Carex tussock's morphological characteristics with water level gradient is similar.With increase of the depth of water,the density,diameter and perimeter of Carex tussock increased first and then decreased,while spacing and height increased.The results showed that the fitting model of Carex coverage,plant height and biomass with water level was significant in Gauss model.Considering the optimum water depth of ecological characteristics of Carex tussock,we arrived the conclusion that the ecological amplitude of Carex tussock was [0,37.7cm] during the peak period of growth.