Environmental Problems and Protection Countermeasures for the Wetlands in Songnen Plain,Oortheast China

Songnen Plain is located in the ecological fragility zone in semi-arid area,and is an alluvial plain from Songhuajiang River and Nenjiang River.A lot of inland marsh wetlands are formed due to special natural environmental characteristics such as clay alluvial parent materials,low basin and so many rivers.These marsh wetlands perform such ecological functions as providing the habits for most rare and endangered water birds,acting as the key area for controlling floods,purifying pollutants adjacent to lands and keeping regional ecological safety and so on.There are many national important wetlands in this region,including Xianghai wetland,Chagan lake wetland,Zhalong wetland,Momoge wetland,Keerqin Wetland ect.Moreover,Xianghai and Zhalong wetlands have been listed in international inportant wetland.The dominant wetland plants are Phragmites australi,Carex and Typha orientalis in these wetlands.Most wetland national or provincial natural reserves have been built for protecting wetland system and wetland biodiversity,since so many birds rely on the wetland habitats.Most wetlands in Songnen Plain have greatly degradated due to unreasonable utilization such as excess reclamation,digging channels and discharging etc.Wetland shrink is obvious and there have been lost 10×104 hm2 reed wetlands since 1970 s,which led to ecological service functions reduced or lost,and most birds or fishes disappeared due to habitats loss.Serious salinity and alkalinity of wetlands have occurred in this region,and sandy lands are expanding,with 56% potential sandy desertification lands and 36% proceeding sandy lands.The wetlands adjacent to sandy lands are facing with sandy threats.Wetland pollution is also more and more serious,resulting in water quality deterioration of wetlands.A lot of untreated waste water from industrial,agricultural and domestic sources has been directly discharged into wetlands,exceeding ecological capacity of wetlands.For example,most of lakes in Zhalong wetland have been heavier eutrophication,with Class V of water quality in Core zone.Xianghai Wetland has also been polluted by heavy metals from coal exploitation in upstream of Huolin river.The irrigation works upstream have led to water shortage of downstream wetlands,improving wetland degradation.Most of roads have been building in order to develop tourism,which led to wetland landscape fragmentation and biodiversity reduce.In addition,the present wetland management systems are not advantageous to wetland protection.The countermeasures and advices are put forward for sustainable management and prevention and cure for wetlands in Songnen Plain.Firstly,it is important to strengthen artificial control of water resources and make the best of flood water in order to ensure wetland ecological water.Secondly,it is necessary to develop herd under ecological safety in order to control salinity,alkalinity and sandy desertification.Thirdly,it is advised to advocate ecological tourism and ecological culture in order to protect wetland integrality and stability.Fourthly, High-efficiency wetland management system and perfect ecological monitoring system must be built to protect habitat safety of water birds.Lastly,wetland pollution must be solved and wetland ecological function planning is also advised in order to keep the harmony of human and wetlands.