The stopovers provide food and habitat for migratory birds and therefore play an important role in facilitating the birds’ completion of their migration. The Hengduan Mountains, which have a complex topography, are located in a large corridor of the Central Asian migratory flyway, so the lakes along the Hengduan Mountains are important for waterbird migration. The existing research on lakes in the Hengduan Mountain area is mostly concentrated in the central and southern parts of the mountains, which proves that many lakes are wintering grounds for migrating birds. We wonder whether the ecological functions of lakes will change more with further elevation. With this question, we conducted four surveys for the seasonal bird survey in Mangcuo Lake, which is located in the northwest of the Hengduan Mountains, in Markam County of Qamdo City, between October 2019 and July 2020. We recorded a total of 6109 birds from 20 species of waterbirds, including 20 species of migratory waterbirds, accounting for 100% of all bird species. The diversity and richness of waterbirds in Mangtso Lake is shown as spring > autumn ≥, summer > winter, with no waterbirds in winter. The black-necked grebe (Podiceps nigricollis), great crested grebe (Podiceps cristatus), bar-headed goose (Anser indicus), and ruddy shelduck (Tadorna ferruginea) were the dominant species in the waterbird community. The highest number of waterbird species and total individuals were found in the transition zone between the marsh wetlands and lakes, and the number of waterbird species differed significantly among habitats (X2 = 14.405, p = 0.000), with habitat complexity being an important factor influencing waterfowl abundance and distribution. The IUCN Red-listed species recorded include the black-necked crane (Grus nigricollis), painted stork (Mycteria leucocephala), and common pochard (Aythya ferina). By comparing with other lakes in Hengduan Mountain, we found that the ecological functions of the plateau lakes in the Hengduan Mountains, to support the life histories of migrating waterbirds, are gradually transforming as the altitude rises, and can be divided into approximately three levels, with the first level of Qionghai, Chenghai, Erhai, and Jianhu at altitudes of 1500–2200 m being the most important ecological function in terms of providing wintering grounds for migrating birds. The second layer, at an altitude of 2400–3300 m, includes Lashihai, Lugu Lake, and Napahai, which are not only wintering wetlands for migratory birds but also important stopover sites. The third layer of Mangcuo Lake, which is above 4000 m above sea level, provides a breeding ground for some migratory waterbirds in summer and a migratory resting place for migratory waterbirds in spring and autumn. We advocate for the importance of Mangcuo Lake in the alpine region along the central Asian flyway, as well as emerging nature conservation action that was previously neglected.

中文翻译：

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横断山脉芒错湖：中亚迁徙路线重要的高山繁殖地和中途停留地

中途停留地为候鸟提供食物和栖息地，对候鸟完成迁徙起到了重要的促进作用。地势复杂的横断山脉地处中亚迁徙迁徙路线的大走廊，因此横断山脉沿线的湖泊是水鸟迁徙的重要场所。现有对横断山区湖泊的研究多集中在山脉的中部和南部，证明许多湖泊是候鸟的越冬地。我们想知道湖泊的生态功能是否会随着海拔的升高而发生更大的变化。带着这个问题，我们对位于昌都市芒康县横断山脉西北部的芒错湖进行了四次季节性鸟类调查。2019年10月至2020年7月，共记录到20种水鸟6109只，其中候鸟20种，占所有鸟类的100%。芒措湖水鸟的多样性和丰富度表现为春季>秋季≥，夏季>冬季，冬季无水鸟。黑颈鸊鷉 (Podiceps nigricollis)、大凤头鸊鷉 (Podiceps cristatus)、斑头雁 (Anser indicus) 和红麻鸭 (Tadorna ferruginea) 是水鸟群落中的优势种。沼泽湿地与湖泊过渡带的水鸟种类和总个体数量最多，生境间水鸟种类数量差异显着（X2 = 14.405，p = 0.000），栖息地的复杂性是影响水禽数量和分布的重要因素。记录在案的 IUCN 红色名录物种包括黑颈鹤 (Grus nigricollis)、彩鹳 (Mycteria leucocephala) 和潜鸭 (Aythya ferina)。通过与横断山其他湖泊的比较，我们发现横断山高原湖泊支持迁徙水鸟生活史的生态功能随着海拔高度的升高而逐渐发生变化，大致可分为三个层次，海拔1500～2200米的琼海、澄海、洱海、鉴湖一级生态功能最为重要，为候鸟提供越冬地。第二层，海拔2400～3300米，包括拉市海、泸沽湖、纳帕海，这里既是候鸟的越冬湿地，也是重要的中途停留地。海拔4000米以上的芒错湖第三层，夏季为部分候鸟提供了繁殖地，春秋两季为候鸟提供了迁徙歇息地。我们提倡中亚迁徙路线沿线高山地区芒错湖的重要性，以及之前被忽视的新兴自然保护行动。