Zhang Pingyang, Zou Ye-Ai, Xie Yonghong, Zhang Siqi, Chen Xinsheng, Li Feng, Deng Zhengmiao, Zhang Hong, Tu Wei
Key Laboratory of Agro-ecological Processes in Subtropical Regions Chinese Academy of Sciences Changsha China.
Dongting Lake Station for Wetland Ecosystem Research Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha China.
Ecol Evol. 2020 Apr 20;10(12):5281-5292. doi: 10.1002/ece3.6272. eCollection 2020 Jun.
East Dongting Lake is a Ramsar site and a particularly important wintering ground for herbivorous geese along the East Asian-Australasian Flyway. The operation of the Three Gorges Dam has changed the water regime and has a significant impact on wetland ecosystems downstream. We studied the responses of two sympatric herbivorous goose species, the Lesser white-fronted goose and Bean goose , to habitat change by investigating their food conditions, habitat selection, and diet composition in the wintering periods of 2016/2017 and 2017/2018, which had early and late water recession, respectively. It was expected that the contrasting water regimes would result in different food conditions and geese responses. The results showed that the food quality and quantity differed significantly between winters. As responses to the high-quantity/low-quality food during 2016/2017, more geese switched to feeding on mudflat and exploited plants such as dicotyledons and moss. The tall swards of spp. (dominant plants in the meadow) that developed during the first growing season decreased the food accessibility during the second growing season and hindered the exploitation of newly generated shoots by the geese, which was further confirmed by our clipping control experiment. Nearly all the geese chose to feed on meadow, and spp. made up the majority of their diet in 2017/2018 when there was more low-quantity/high-quality food. Compared with the globally vulnerable Lesser white-fronted geese, the larger-sized Bean geese seemed to be less susceptible to winter food shortages and exhibited more stable responses. We concluded that the food quality-quantity condition was the external factor influencing the geese responses, while morphological and physiological traits could be the internal factors causing different responses between the two species. This study enhanced the understanding of the influence that habitat change exerts on herbivorous geese in their wintering site in the context of the Three Gorges Dam operation. We suggested that regulating hydrological regime was important in terms of wetland management and species conservation.
东洞庭湖是拉姆萨尔湿地，也是东亚-澳大利西亚候鸟迁徙路线上食草鹅类尤为重要的越冬地。三峡大坝的运行改变了水情，对下游湿地生态系统产生了重大影响。我们通过调查2016/2017年和2017/2018年越冬期两种同域分布的食草鹅类——小白额雁和豆雁的食物状况、栖息地选择和饮食组成，研究了它们对栖息地变化的响应，这两个越冬期分别出现了较早和较晚的水位消退。预计不同的水情会导致不同的食物状况和鹅类的响应。结果表明，两个冬季的食物质量和数量存在显著差异。作为对2016/2017年高数量/低质量食物的响应，更多的鹅转而以泥滩和双子叶植物、苔藓等可利用植物为食。在第一个生长季节生长起来的 spp.（草甸中的优势植物）的高大草皮，在第二个生长季节降低了食物的可获取性，并阻碍了鹅类对新长出嫩枝的利用，我们的刈割控制实验进一步证实了这一点。2017/2018年，当有更多低数量/高质量食物时，几乎所有的鹅都选择以草甸为食， spp. 占其饮食的大部分。与全球易危的小白额雁相比，体型较大的豆雁似乎对冬季食物短缺的敏感度较低，表现出更稳定的响应。我们得出结论，食物质量-数量状况是影响鹅类响应的外部因素，而形态和生理特征可能是导致两个物种产生不同响应的内部因素。本研究增进了我们对三峡大坝运行背景下栖息地变化对越冬地食草鹅类影响的理解。我们建议，调节水文状况对于湿地管理和物种保护至关重要。
