Mapping wader biodiversity along the East Asian—Australasian flyway

Background and goalThe study is conducted to facilitate conservation of migratory wader species along the East Asian-Australasian Flyway, particularly to 1) Identify hotspots of wader species richness along the flyway and effectively map how these might change between breeding, non-breeding and migratory phases; 2) Determine if the existing network of protected areas (PA) is sufficient to effectively conserve wader biodiversity hotspots along the EAAF; 3) Assess how species distribution models can provide complementary distribution estimates to existing BirdLife range maps.MethodsWe use a species distribution modelling (SDM) approach (MaxEnt) to develop temporally explicit individual range maps of 57 migratory wader species across their annual cycle, including breeding, non-breeding and migratory phases, which in turn provide the first biodiversity hotspot map of migratory waders along the EAAF for each of these phases. We assess the protected area coverage during each migration period, and analyse the dominant environmental drivers of distributions for each period. Additionally, we compare model hotspots to those existing range maps of the same species obtained from the BirdLife Internationals’ database.ResultsOur model results indicate an overall higher and a spatially different species richness pattern compared to that derived from a wader biodiversity hotspot map based on BirdLife range maps. Field observation records from the eBird database for our 57 study species confirm many of the hotspots revealed by model outputs (especially within the Yellow Sea coastal region), suggesting that current richness of the EAAF may have been underestimated and certain hotspots overlooked. Less than 10% of the terrestrial zones area (inland and coastal) which support waders are protected and, only 5% of areas with the highest 10% species richness is protected.Main conclusionsThe study results suggest the need for new areas for migratory wader research and conservation priorities including Yellow Sea region and Russian far-East. It also suggests a need to increase the coverage and percentage of current PA network to achieve Aichi Target 11 for Flyway countries, including giving stronger consideration to the temporal dynamics of wader migration.研究背景与研究目标 本研究旨在助力东亚-澳大利西亚迁飞区（East Asian-Australasian Flyway, EAAF）迁徙鸻鹬类物种的保护工作，具体目标包括：1） 明确该迁飞区沿线鸻鹬类物种丰富度热点区域，并精准绘制这些热点在繁殖期、非繁殖期与迁徙期的动态变化；2） 评估现有保护区（protected areas, PA）网络是否足以有效保护东亚-澳大利西亚迁飞区的鸻鹬类生物多样性热点；3） 探究物种分布模型（species distribution modelling, SDM）如何为现有国际鸟盟（BirdLife International）物种分布范围图谱提供补充性的分布估算结果。 研究方法 本研究采用物种分布模型框架，以最大熵模型（MaxEnt）为核心方法，为57种迁徙鸻鹬类构建覆盖其全年生活周期（包括繁殖期、非繁殖期与迁徙期）的分阶段单物种分布范围图谱，进而首次生成东亚-澳大利西亚迁飞区各阶段迁徙鸻鹬类的生物多样性热点分布图。本研究同时评估各迁徙阶段的保护区覆盖情况，并分析各阶段物种分布的主要环境驱动因子。此外，本研究将模型生成的热点区域与从国际鸟盟数据库获取的同一物种现有分布范围图谱进行对比。 研究结果 本研究的模型结果显示，相较于基于国际鸟盟分布范围图谱构建的鸻鹬类生物多样性热点图，本研究得到的物种丰富度格局整体数值更高，且空间分布特征存在显著差异。来自eBird数据库的57种研究物种的野外观测记录，验证了模型输出所揭示的多数热点区域（尤其是黄海沿海区域），这表明东亚-澳大利西亚迁飞区当前的物种丰富度可能被低估，且部分热点区域遭到忽略。支撑鸻鹬类生存的陆地生境（包括内陆与沿海区域）中，仅有不足10%的面积得到保护；而在物种丰富度排名前10%的区域中，仅5%的面积被纳入保护范围。 主要结论 本研究结果表明，亟需针对迁徙鸻鹬类划定新的研究与保护优先区域，其中包括黄海区域与俄罗斯远东地区。同时，为使迁飞区各国达成《爱知生物多样性目标11》（Aichi Target 11），需扩大现有保护区网络的覆盖范围与占比，其中应充分重视鸻鹬类迁徙的时间动态特征。