Study On The Restoration Of Degraded Coastal Wetlands In The Yellow River Delta:a Restoration Model Based On Micro Topography Construction

The degradation the Yellow River delta coastal wetland is becoming more and more serious affected by climate change,land-sea interaction and human disturbance.In order to provide reference for ecological restoration in the region,a typical degraded area was selected and the degradation causes were analyzed.The main aim of this study was to explore a restoration model which could restore vegetation cover and ecological function synchronously.The main conclusions are as follows:(1)In the study area,decrease of water supply,uneven distribution of precipitation and weakening of the tidal effect caused by the shoreline migration are main factors for the coastal wetlands degradation.Meanwhile,the avian habitat function has been impaired seriously for the homogenous habitat.In order to achieve the rational use of water resource and create a diverse habitat,an ecological engineering project was designed and implemented combined with micro-topography modification and water-level regulation.(2)Through a period of 1 and a half years of recovery after the implementation of ecological engineering,the soil salt content decreased significantly.The vegetation cover and water area increased significantly,with the bare land area decreased correspondingly.In the dry season,the water area increased by 6.3 times,with the proportion increased from 2.1%to 15.3%.The vegetation coverage of the micro topography area increased from 27.4%to 37.40%.The composition proportion of vegetation,water area and bare land has significantly improved in both dry and wet seasons.(3)There were 14 species of macroinvertebrate have been found from starch in the restoration area,with Chironomus sp.as the pioneer and dominant species.Some kinds of annelid,arthropod and fishes also began to appear.From July 2015 to April 2017,74 avian species,belonging to 10 orders and 21 families,were recorded in the restoration area,with 29.6%belonging priority protected avian species above provincial level.The bird ecotype was complete,with swimming bird(52.1%)and wading bird(38%)as the main species.Scansores,songbirds and raptors also emerged.Migratory birds(50.7%)and passing birds(31%)accounted for the major proportion.Compared with the same period in 2015,the species and number of birds were significantly increased in 2016 and 2017,suggesting that the bird habitat function of the restoration area has significantly improved.(4)Compared with the two main traditional restoration measures,including enclosure-freshwater supplement model and fractional habitat improvement model,the designed restoration model could habitat more birds with higher diversity,and is more suitable for ecological restoration of the degraded coastal wetland in the region.In a word,the designed restoration model,which combined micro-topography modification and water-level regulation,could improve landscape effect,vegetation cover and ecological function synchronously.Therefore,it has better ecological restoration effect could be applied to ecological restoration in the Yellow River Delta.