鄱阳湖周边稻田对白鹤的承载力

鄱阳湖是世界重要的候鸟越冬地,承载了全球约98%的白鹤(Leucogeranus leucogeranus)。然而,近年来鄱阳湖沉水植被退化严重,白鹤的传统食物苦草(Vallisneria spp.)冬芽丰富度急剧减少。食物短缺导致白鹤的觅食生境由自然湿地的浅水生境转移至稻田、藕塘等人工生境,稻田在白鹤保护中发挥的作用日益突出。了解鄱阳湖周边稻田对白鹤的承载力可为白鹤的保护和管理提供科学依据。为此,调查了鄱阳湖周边稻田散落稻谷的生物量,测量了稻谷的营养成分,并利用遥感影像对鄱阳湖周边10 km范围内稻田的总面积进行估算,从而得出鄱阳湖周边稻田散落稻谷能提供的总能量。然后,计算稻田中以稻谷为主要食物的6种鸟类的日能量消耗,用以表示日能量摄入。最后,依据稻田能提供的总能量、鸟类的日能量摄入、鸟类的越冬时长、以及各种鸟类的数量占比,计算得出鄱阳湖周边稻田能承载的白鹤数量。结果表明,鄱阳湖周边稻田散落稻谷的生物量为6.494 g/m²,环鄱阳湖周边10 km范围内稻田的总面积为1984.46 km²,这些稻田能承载的鸟类总数量为140860只,其中能承载的白鹤数量为10775只,超过了全球白鹤的总数量(3500-4000只)。因此,鄱阳湖周边稻田能为白鹤等鸟类提供丰富的食物资源。

Carrying capacity of Siberian cranes (Leucogeranus leucogeranus) in the rice fields around Poyang Lake

Poyang Lake is one of the world''s most important wintering grounds for migratory birds, supporting approximately 98% of the world''s Siberian cranes (Leucogeranus leucogeranus). However, the submerged plants at Poyang Lake have degraded seriously in recent decades. The abundance of tubers of Vallisneria spp., the original food of the Siberian crane, has declined sharply. Food shortages have led to Siberian cranes shifted their foraging habitat from shallow waters in the natural wetlands to artificial habitats including rice fields and lotus root ponds. Rice fields play an increasing important role in Siberian crane protection. Understanding carrying capacity of Siberian cranes in the rice fields around Poyang Lake could provide scientific basis for bird protection and management. Therefore, in this study, we firstly investigated the biomass of spilled rice in the rice fields around Poyang Lake, measured the nutritional contents of rice, and estimated the total area of the rice fields within 10 km around Poyang Lake using remote sensing images. Based on these parameters, we could obtain the total energy provided by the spilled rice in the rice fields around Poyang Lake. Then, the daily energy consumption of the six bird species primarily consuming rice in the rice fields was calculated to represent their daily energy intake. Finally, the carrying capacity of Siberian cranes in the rice fields around Poyang Lake was calculated based on the total energy provided by the rice fields, the daily energy intake of birds, the wintering duration of birds, and the proportion of each bird species. The results showed that the biomass of spilled rice was 6.494 g/m², and the total area of the rice fields within 10 km around Poyang Lake was approximately 1984.46 km². The rice fields could support 140860 birds, among which 10775 were Siberian cranes, exceeding the existing global number of Siberian cranes (3500-4000). Therefore, the rice fields around Poyang Lake could provide abundant food resources for Siberian cranes.