Cornell Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA.
Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK.
Proc Biol Sci. 2022 Aug 10;289(1980):20221105. doi: 10.1098/rspb.2022.1105.
The presence of migratory birds on islands results in seasonal variation in species richness. These patterns and their geographical correlates within the context of island biogeography theory have not been examined. We used 21 years of bird observations on 690 islands from eBird to determine how seasonal species richness estimates vary as a function of island area, isolation and latitude. Species richness was highest on islands within the northern mid-latitudes during migration and on islands within tropical latitudes during the non-breeding season. Area defined positive, nonlinear relationships with species richness across seasons, with the steepest slopes occurring with islands greater than 1100 km. Distance to mainland defined negative, nonlinear relationships with species richness across seasons, with the strongest slopes occurring with islands located greater than 150 km from the mainland. Species-area relationships were weakest for the most remote islands and strongest for islands at intermediate distances to the mainland. Intermediate proximity to other islands was a poor predictor of species richness. Our findings emphasize the presence of seasonally dynamic geographical relationships, the enhanced role of evolutionary processes on larger islands, the unique ecology of the world's most remote islands, and the importance of islands as stopover sites and wintering grounds for migratory bird species.
候鸟在岛屿上的存在导致物种丰富度呈现季节性变化。在岛屿生物地理学理论的背景下，这些模式及其地理相关性尚未得到检验。我们使用 eBird 上 690 个岛屿 21 年的鸟类观测数据，确定了季节物种丰富度估计值如何随岛屿面积、隔离度和纬度而变化。在候鸟迁徙期间，高纬度地区的岛屿和非繁殖季节的热带地区的岛屿上的物种丰富度最高。在整个季节中，面积与物种丰富度之间呈正、非线性关系，岛屿面积大于 1100 公里时斜率最大。距离大陆与物种丰富度之间呈负、非线性关系，岛屿距离大陆大于 150 公里时斜率最大。最偏远岛屿的种-面积关系最弱，而距离大陆中等距离的岛屿的种-面积关系最强。与其他岛屿的中等接近程度不是物种丰富度的良好预测指标。我们的研究结果强调了季节性动态地理关系的存在、较大岛屿上进化过程的增强作用、世界上最偏远岛屿的独特生态以及岛屿作为候鸟停歇地和越冬地的重要性。
