松嫩平原白鹤种群动态对水文条件及食源丰富度波动效应的响应及机理研究

Siberian crane (Grus leucogeranus Pallas) is an endangered migrating wader. The eastern population stopover at Songnen Plain, accounted for approximately 99% of the total number of globally. In recent years, the development of wetland ecological restoration project has restored the wetland habitat, meanwhile changed the rule of original hydrological drastic fluctuation in the semi-arid region, resulting in the changes of attributes and distribution pattern of wetland patches. The Siberian crane stopover number fluctuated during this period. The essential reason which caused this phenomenon should be further discussed. Therefore, the response of the stopover number and distribution pattern of Siberian crane to the fluctuation effect of hydrological conditions (water depth, waterlogging time, water area in wetland) and growth and distribution of food source for Siberian cranes will be investigated. We will develop this project through interpreting the remote sensing images of different period before and after the wetland ecological restoration project, and combine the field investigation and control experiment in laboratory. Moreover, we will try to reveal the effect of wetland ecological restoration project on Siberian crane stopover, and illustrate how the Siberian cranes will response for the change of the threshold of wetland hydrological condition. The results will be supposed to provide a scientific basis for creating more suitable habitat for large waterfowls represented by Siberian crane, the management of the same latitude or the same type marsh wetland ecosystems, as well as the construction of ecological engineering.

白鹤是一种濒危迁徙涉禽，其东部种群以松嫩平原为迁徙中转地，数量占世界总数的99%以上。近年来松嫩平原湿地生态恢复工程建设的开展，在恢复湿地生境的同时，也改变了这一半干旱区原有的水文剧烈波动规律，导致湿地斑块的属性和分布格局发生了变化。白鹤停歇数量在这一时期也发生了剧烈的波动，而引起这一现象的本质原因还需深入探讨。因此，本研究通过解译湿地生态恢复工程建设前后不同时期遥感影像，结合野外调查和室内控制实验，深入开展白鹤种群停歇数量、分布格局对湿地水深、水淹时间和水面面积等水文条件及白鹤食源植物生长、分布波动效应的响应研究，明晰湿地恢复工程对白鹤中转停歇的影响，阐明白鹤在迁徙中转地对湿地水文条件阈值变化的响应机理。期望为以白鹤为代表的大型水禽创造更适宜的栖息生境，并为同纬度或同类型的沼泽湿地生态系统管理和生态工程建设提供科学依据。

白鹤（Grus leucogeranus Pallas）为IUCN濒危物种红色名录极危级物种。其中，东部种群占世界总数的99%以上。白鹤在松嫩平原西部进行迁徙能量补充，每次停留时间约45 ~ 60天。近些年，随着我国生态恢复工程建设的开展，松嫩平原湿地面积得到明显提升。生态工程建设引起了湿地水淹规律等水文变化，改变了湿地斑块的属性和分布格局，这是引起白鹤在此地中转停歇数量不稳定的主要因素。因此，本项目通过分析白鹤种群在中转停歇地数量、分布格局变化与湿地水深、水面面积和水淹时间等水文条件变化和食物资源丰富度之间的相互关系，明确影响白鹤停歇的关键水文因子及其阈值，阐明白鹤对湿地水文波动变化的响应机理，并根据研究结果为生态工程建设提供优化解决方案。结果表明：综合分析白鹤适宜停歇水位范围及其食物扁秆荆三棱地上生物量、地下生物量适宜水位条件，0 m ~ 0.3 m为既适宜白鹤停歇又能满足扁秆荆三棱生长的最适水位范围；研究表明，适宜白鹤中转迁徙停歇生境应具备如下的水体特征：水体周长面积分维数最适阈值范围在1.27-1.30，景观分离指数最适阈值范围在0.73-0.95，聚合度最适阈值范围在80.97-91.36；计算得到了白鹤迁徙中转的历史停歇地最小生态需水量和最适生态需水量分别为2.47×108 m3 ~ 3.66×108 m3和4.96×108 m3 ~ 10.36×108 m3。应用建立的三维静态模型对补水效果进行了模拟，模拟结果与同期遥感预期效果存在一定的偏差。为了校正生态需水量，根据β值为0.04、0.07、0.20、0.70的百分比率进行三维模拟，结果表明满足白鹤停歇需求的最小β值为0.07，其对应的最小生态需水量为3.75×108 m3，适宜β值为0.20，其对应的最适生态需水量为5.21×108 m3。本项目针对白鹤对湿地变化响应的研究对濒危物种的保护提供了理论依据，反映了迁徙涉禽对湿地变化的普遍规律，为同纬度或同类型的沼泽湿地生态系统管理和生态工程建设提供科学决策。为我国松嫩鹤乡国家公园建设提供了科学支撑。