Community Characteristics And Habitat Analysis Of Wintering Waterfowl Between Different Cultivation Of Rice Paddy In Chongming Dongtan

Wetlands are a valuable natural resource and an important part of ecosystems,with irreplaceable comprehensive functions.Wetlands provides natural habitats and sustenance for many wild animals and plants,it provides a variety of ecological services for human beings as well,such as water conservation,excess flood water storage,it contributes to climate control.China's wetlands area is about 6000 million hm2(which does not include rivers,ponds,etc.),accounting for 10%of the world's wetlands area,and ranking first in Asia.Rich tidal resources,unique hydrological environment,also provides an important foraging,resting habitat and wintering place for the large number of migratory waterfowl.Due to the impact of land reclamation activities,a lot of natural wetlands have been degraded and lost.Despite the increasing emphasis on wetland protection and restoration in recent years,the rapid population growth and the rapid development of the economy,the degradation and loss of wetland habitats is still an on-going problem.Waterbirds are key species in a wetland ecosystem,located at the top of the food chain,birds maintain the virtuous circle of wetland ecosystem,which is sensitive to environmental change and plays an important role in environmental monitoring.Different waterfowls have different body structures and different preferred habitats,different wetland habitats attract different types of water birds.Waterfowls are highly reliant on wetlands for food and shelter.With their numbers threatened due to the loss and degradation of their wetland habitatsIn the absence of natural wetlands,waterfowls have had to adapt to changes in the environment and are dependent on the artificial wetlands as a supplement.Studies have shown that artificial wetlands cannot wholly replace natural wetland despite its positive effects on conservation.Numerous studies have shown that the quality of man-made wetlands depends on the structure and management of the habitat,and the effective management of wetlands can enhance the waterfowl conservation effects of man-made wetlands.Shanghai Chongming Dongtan is located on the eastern end of Chongming Island,located in the Yangtze River,in Asia and Australian bird migration routes.It is an important transition point along the migratory route of birds providing much needed food replenishments and shelter for these migratory birds along the way.Over a million birds stopover in shanghai mainly migratory and winter migrants that include:Anseriformes,Ciconiiformes and Griuiformes.Chongming Dongtan is one of the key areas of land reclamation in Shanghai,most of the natural beaches are used for a variety of agriculture and aquaculture development.Reclamation has caused the natural ecological function of natural beaches to be greatly reduced which has led to the sharp decline in the diversity of water bird species.The Chongming Dongtan Natural reserve is a hybrid combination of man-made and natural wetlands.Studies have proven that the artificial restoration of wetlands is a great supplement to the loss of natural ones.Land reclamation is mainly used for the agriculture of rice.Depending on the different forms of management,it can be divided into two main forms traditional and mechanized.The traditional form of rice paddy cultivation uses manual and labor intensive form of planting and harvesting rice fields,the mechanized form of rice paddy cultivation uses modern machinery and methods of planting,and harvesting rice fields.The two different forms of rice cultivation both have different land requirements.These differences have a huge impact on the waterfowls and wetlands.A field survey was conducted in 2013,2014 and 2015.we selected five samples from the traditional rice paddy fields and the mechanized rice paddy fields.Using the T test to compare the two different waterfowl communities in these 2 areas.The habitat factor analysis was carried out by Linear Regression(Backward Elimination).The aim of this study was to explore the differences in habitat status and waterfowl community characteristics of paddy fields under different management models,and the in terannual differences of rice fields in the same model,and to analyze the main habitat factors affecting the characteristics of waterfowl communities.The main conclusions are as follows:1.Different cultivation systems lead to different impacts on a habitat,mainly in the water level and vegetation configuration.The traditional cultivation of rice paddy is generally in a state of water in winter,water conditions are appropriate,some rice retained,and there are some reeds to increase habitat concealment;mechanized cultivation of rice paddy is generally in an idle state in winter,with generally no water,no Vegetation or low vegetation surrounded by a narrow diversion ditch.2.Compared with the data of the waterfowl community in 2013,2014,2015,the traditional system is better than that of mechanized ones.The number of species and types of waterfowl in the paddy field was higher than that of mechanized paddy fields in 2013,but the difference was not significant.This might be due to the early improvement made to the habitat that was not too obvious in 2013.In 2014 and 2015,the number and species of waterfowl in traditional rice paddy were significantly higher than that of mechanized ones,indicating that the difference between the different cultivation systems was stable and objective.And the number and species structure of the waterfowl in the two different types of paddy fields are quite different.The number and species of the waterfowl in the traditional rice paddy were dominated by the Anseriformes,while the waterfowl in the mechanized paddy were mostly Podicipediformes.3.The results show that compared with 2013,the number and species of waterfowls in traditional rice paddy in 2014 and 2015 increased significantly,and the numbers and species of waterfowls in 2015 were lower than those in 2014,but the difference were not significant.It shows the attractant effect of traditional rice paddy has generally improved.Compared to the early 2013 renovation,relatively mature in 2014 and 2015 have reached levels better than that of the early waterfowl conservation effects.Different from traditional rice paddy,number and species at mechanized paddy were not significantly different,because of the high randomness and few waterfowl number.Compared with the three-year waterfowl community structure,there is almost no change of quantitative structure year after year in traditional manage pattern rice paddy,mechanized manage pattern rice paddy is not obvious changes in the trend.4.The results of habitat analysis show that the proportion of open water area is the most important factor affecting the species and quantity distribution of waterfowl.The paddy fields with better water area and better condition has better waterfowl bidding effect.The analysis of habitat analysis of different types of waterfowl shows that,the number of Anseriformes had highly positive significant correlation with the proportion of open water area.The number of Ciconiiformes had negative significant correlation with the proportion of open water area and human disturbance.The number of Griuiformes had negative significant correlation with the proportion of open water area,but positive significant correlation with human disturbance.The number of Podicipediformes had highly positive significant correlation with the variation of water depth,but highly negative significant correlation with the proportion of open water area.It is related to the habitat preference and living habits of different waterfowl.There is no significant correlation between the number of Charadriiformes and those habitat factors.Chongming Dongtan is an important stop for winter bird migration routes and waterfowl wintering,In recent years,the loss and degradation of local natural wetlands has resulted in a decline in the number and quantity of waterfowl.Although the structure and function of constructed wetlands are still different from those of natural wetlands,the extensive distribution of paddy fields can maximize the ecological conservation effect and reduce the adverse effects of natural wetland loss on waterbirds through targeted management.