苏打水湖是一些生产力最高的水生生态系统。1它们的碱性盐水维持着独特的浮游植物群落2,3,并为包括无脊椎动物在内的高度专业化的生物多样性提供了重要的栖息地,特有鱼类,和小火烈鸟(腓尼基亚斯小调)。1,4超过四分之三的小火烈鸟居住在东非的苏打湖5;然而,人口在下降。6下降可归因于他们高度专业化的蓝细菌饮食7和对对气候波动和流域退化高度敏感的苏打湖喂养栖息地网络的依赖。8,9,10,11,12然而,由于缺乏原位水质和水文数据以及对这些水域的不定期监测,因此尚未评估不断变化的栖息地可用性。13此处,我们将卫星地球观测和较小火烈鸟丰度观测相结合,以量化东非22个苏打湖几十年来生产力和生态系统健康的时空趋势。我们发现,较小的火烈鸟分布最好用浮游植物生物量来解释,食物供应的指标。然而,时间序列分析显示,从1999年到2022年,浮游植物生物量显着下降,这很可能是由于湖泊水位的大幅上升所致。生产力的下降降低了健康苏打湖生态系统的可用性,最著名的是赤道肯尼亚和坦桑尼亚北部。我们的研究结果凸显了东非小火烈鸟和其他苏打湖生物多样性的脆弱性。特别是在气候变化下预测降雨量增加的情况下.14,15,16在没有改进湖泊监测和流域管理实践的情况下,苏打水湖生态系统可能会被超越其环境容忍度。视频摘要.
Soda lakes are some of the most productive aquatic ecosystems.1 Their alkaline-saline waters sustain unique phytoplankton communities2,3 and provide vital habitats for highly specialized biodiversity including invertebrates, endemic fish species, and Lesser Flamingos (Phoeniconaias minor).1,4 More than three-quarters of Lesser Flamingos inhabit the soda lakes of East Africa5; however, populations are in decline.6 Declines could be attributed to their highly specialized diet of cyanobacteria7 and dependence on a network of soda lake feeding habitats that are highly sensitive to climate fluctuations and catchment degradation.8,9,10,11,12 However, changing habitat availability has not been assessed due to a lack of in situ water quality and hydrology data and the irregular monitoring of these waterbodies.13 Here, we combine satellite Earth observations and Lesser Flamingo abundance observations to quantify spatial and temporal trends in productivity and ecosystem health over multiple decades at 22 soda lakes across East Africa. We found that Lesser Flamingo distributions are best explained by phytoplankton biomass, an indicator of food availability. However, timeseries analyses revealed significant declines in phytoplankton biomass from 1999 to 2022, most likely driven by substantial rises in lake water levels. Declining productivity has reduced the availability of healthy soda lake ecosystems, most notably in equatorial Kenya and northern Tanzania. Our results highlight the increasing vulnerability of Lesser Flamingos and other soda lake biodiversity in East Africa, particularly with increased rainfall predicted under climate change.14,15,16 Without improved lake monitoring and catchment management practices, soda lake ecosystems could be pushed beyond their environmental tolerances. VIDEO ABSTRACT.