Study On The Conservation And Restoration Of The Habitat For Migratory Siberian Crane(Scirpus Planiculmis)Eastern Population In Momoge National Nature Reserve,China

Siberian crane(Grus leucogeranus) is the CR species in the Red list of threatened species. The global number is about 4000. Currently, the researchers have paid attention to protect and study the Siberian crane and their stopover sites. Momoge National Nature Reserve is an important stopover site for eastern population of Siberian crane in migration route. The stopover number is over 95% of total population. In recent years, the issues about water shortage and unscientific water supplement have been occurred in Siberian crane stopover site because of environmental change and unsuitable management. This can affect the normal stopover for Siberian crane and increasement of effective habitat. It is important to note that scientific and reasonable use of water resources and conserve Siberian crane stopover site have been the key problems for protecting Siberian crane.In this paper, the hydrological changeof historical and current stopover sitesfor Sibeican crane, growth situation of Siberian crane food, variation of Siberian crane number from 1983 to 2013 were collected based on environmental ecology and main ecological issue in Momoge Reserve. The restoration project in current stopover site was evaluated by hydrological model. The unscientific water supplement strategy was adjusted. The ecological capacity of current stopover site was estimated, which indicate that it is important to restore historical stopover site. The water environment conditions with different water supplement in historical stopover site were simulated by using the calculation of ecological water demand and three-dimensional dynamicsimulation under two conditions. The water supplement suggestions were raised.The main conclusions are as follows.(1) The relationships between Siberian crane, the ground and underground biomasses of Scirpus planiculmis and hydrological condition were studied. The results show that the regions with water levels for growth of Scirpus planiculmis were-0.05m~0.3m. When the water level was about 0.1m, the ground and underground biomasses of Scirpus planiculmis reached to maximum. Siberian cranes usually stop and feed in the regions with water levels of 0~0.5m. The number is account for 92.70% of total Siberian crane stopover population. Therefore, the optimal water level for Siberian crane stopover and growth of Scirpus planiculmisis 0m~0.3m. The determined water level provides a scientific evidence for calculating supplement water of Siberian crane stopover site.(2) A wetland restoration project was conducted in Momoge National Nature Reserve in order to protect Siberian crane current stopover site. In this paper, the daily water level change was simulated by hydrological model and the differences of Siberian crane number, hydrological conditions and plant communities were investigated before and after restoration project. The results indicate that the Siberian crane population and its primary food(Scirpus planiculmis) distribution area increased in the first three years of the restoration project relative to the levels prior to the project. The daily water levels ranged from approximately-0.2~0.2m, which is ideal for a stopover habitat for this waterbird.The wetland restoration project plays an important role in protecting Siberian crane stopover site and providing habitat. However, Siberian crane numbers sharply decreased in the later period of the restoration project. The average daily water level was approximately 0.6m, and the distribution area of Scirpus planiculmis decreased, which affected the incidence of Siberian crane stopovers. Furthermore, an effective water management strategy was established to protect Siberian crane populations and habitats based on the water level change of optimum stopover period for Siberian crane. In summer, continuous water supplementation based on varying water demands was used to guarantee the growth of Scirpus planiculmis and provide a suitable water level for Siberian crane stopovers in autumn. At the end of autumn, rapid water supplementation was used to maintain suitable water levels for the following spring.(3)The carryingcapacity of Siberian crane was established from observing Siberian feeding behavior and calculating food reserves based on theory and method of basic ecology in restored current stopover site. The results show that a Siberian crane intakes1.49×105 tubers of Scirpus planiculmis for one year in Momoge Reserve and the theoretical Siberian crane stopover number is about 2765 in current stopover site. In recent year, the Siberian crane stopover number have reached and exceeded this threshold value. In order to decrease the pressure of current stopover site, prevent stopover environmental deterioration and meet the demand for food, the optimum stopover region of Siberian crane should be enlarged, which has been the necessary measure for protecting the Siberian crane.(4) The water demands for optimum stopover site were calculated by the variation of Siberian crane number and wetland area in historical stopover site form 1988 to 2007. The results show that the minmal and optimal water demands are 2.47×108m~3~3.66×108m~3 and 4.96×108m~3~10.36×108m~3, respectively. In order to examine the accuracy of calculation, an established three-dimensional static model for study area was used to calculate water demand of different thresholds and simulate three-dimensional dynamic water supplement based on β values. The corrected minimal and optimal water demands for historical stopover site are3.75×108m~3 and 5.21×108m~3, respectively. An ecological water supplement strategy was established according to corrected water demand. There are three modes for water supplement based on incoming water value and approach. First, when the water was sufficient, we adopted the mode of annual continue water supplement based on hydrological law of Nenjiang River and actual situation of water supplement area. Second, the water supplement simulated flood was adopted according to period of wet year and dry year. Third, partition water supplement was adopted in the condition of insufficient incoming water.The optimal water level for Siberian crane stopover and growth of Scirpus planiculmis was proposed based on the analysis results. It can be found that the water level is ideal for Siberian crane stopover in the first period of restoration project and affected the Siberian crane stopover in the later period of restoration project. Therefore, an effective water management strategy was established. However, the Siberian crane stopover number has exceeded the threshold value. It is important to restore historical stopover site. The corrected minimal and optimal water demands for historical stopover site are 3.75×108m~35.21×108m~3, respectively. The restoration method and management plan to protect Siberian Cranes in this area can be a reference point for restoring lager wader stopover sites in Songnen Plain or other areas in China.