Study On Effects Of Waterlogging Time And Animal Feeding On The Degradation Of Red Beach

Red Beach,one typical natural landscape of the estuary wetland in northern China,is composed by Suaeda heteroptera community.As an important tourism resource and wetland resource in Panjin,Liaoning province,the red beach had degradated severely in recent years,which seriously threatened the realization of its ecological value and the development of landscape resources.Based on the current degeneration of Red Beach,in this paper,the effects of waterlogging and animal feeding on degradation of Liaohe Red Beach were discussed by field investigation and observation,indoor control experiment,numerical simulation and remote sensing image interpretation.The waterlogging depth and the waterlogging time in different density of Suaeda heteroptera communities were investigated by laying water level gauges at Liaohe estuary,and the vegetation density and salinity in different density of Suaeda heteroptera communities were investigated simultaneously at the neap tide monthly.The observation results showed that the density of Suaeda heteroptera community in Liaohe estuary was significantly affected by soil salinity,waterlogging depth and waterlogging time.In the Liaohe wet season,the average waterlogging time in the densely growing area of Suaeda heteroptera community was 1.56 h,while the average waterlogging time in the low distribution density areas of Suaeda heteroptera community was 3.1h.In order to grasp the suitable waterlogging time for the growth of Suaeda heteroptera community,this paper paid attention to the hydrodynamic conditions in the Liaohe estuary region by numerical simulation,and the distribution of waterlogging time was calculated through the dry and wet judgment.According to the field observation data,the area of the waterlogging time from 1.5h to 2.8h in August 2013(the wet season)was extracted,and then the vegetation distribution information obtained by supervised and classified of remote sensing images was compared.The results showed that the simulation effect was in good agreement with the actual vegetation growth area.And waterlogging time and the intertidal vegetation were distributed in a strip shape,which indicated that the waterlogging time was an important factor to determine the distribution of Suaeda heteroptera.On the other hand,the indoor feeding experiment was carried out to study the feeding habits of Helice tientsinensis in Liaohe estuary Red Beach by setting different food source groups.The results demonstrated that compared with Phragmites communis,the Helice tientsinensis of Liaohe estuary had obvious feeding preference for the high water content of the Suaeda heteroptera.In order to find out the range of feeding effects of Helice tientsinensis,the spatial and temporal distribution characteristics of the Helice tientsinensis of Liaohe estuary Red Beach were investigated through a total of 9 sampling surveys were carried out in 5 sections in five habitats and 9 sections in different areas in Liaohe estuary in 2016-2017.The results showed that the distribution of Helice tientsinensis was accompanied by the whole growing season of the Suaeda heteroptera,and it was also widely distributed in the Liaohe estuary Red Beach area.Therefore,selective feeding of Helice tientsinensis is not conducive to the growth of Suaeda heteroptera community in Liaohe estuary,and it is a factor that cannot be ignored in the degradation of the red beach.