Groundwater is the most ubiquitous source of liquid freshwater globally, yet its role in supporting diverse ecosystems is rarely acknowledged^1,2. However, the location and extent of groundwater-dependent ecosystems (GDEs) are unknown in many geographies, and protection measures are lacking^1,3. Here, we map GDEs at high-resolution (roughly 30 m) and find them present on more than one-third of global drylands analysed, including important global biodiversity hotspots⁴. GDEs are more extensive and contiguous in landscapes dominated by pastoralism with lower rates of groundwater depletion, suggesting that many GDEs are likely to have already been lost due to water and land use practices. Nevertheless, 53% of GDEs exist within regions showing declining groundwater trends, which highlights the urgent need to protect GDEs from the threat of groundwater depletion. However, we found that only 21% of GDEs exist on protected lands or in jurisdictions with sustainable groundwater management policies, invoking a call to action to protect these vital ecosystems. Furthermore, we examine the linkage of GDEs with cultural and socio-economic factors in the Greater Sahel region, where GDEs play an essential role in supporting biodiversity and rural livelihoods, to explore other means for protection of GDEs in politically unstable regions. Our GDE map provides critical information for prioritizing and developing policies and protection mechanisms across various local, regional or international scales to safeguard these important ecosystems and the societies dependent on them.

地下水是全球最普遍的液态淡水来源，但其在支持多样化生态系统方面的作用却很少得到承认^1,2 。然而，许多地区依赖地下水的生态系统 (GDE) 的位置和范围尚不清楚，而且缺乏保护措施^1,3 。在这里，我们以高分辨率（大约 30 m）绘制 GDE 地图，发现它们存在于所分析的全球三分之一以上的旱地中，包括重要的全球生物多样性热点⁴ 。在以畜牧业为主、地下水耗竭率较低的景观中，GDE 更为广泛和连续，这表明许多 GDE 可能已经因水和土地利用实践而消失。然而，53% 的 GDE 存在于地下水呈下降趋势的地区，这凸显了保护 GDE 免受地下水枯竭威胁的迫切需要。然而，我们发现只有 21% 的 GDE 存在于受保护的土地上或制定了可持续地下水管理政策的管辖区，因此呼吁采取行动保护这些重要的生态系统。此外，我们研究了 GDE 与大萨赫勒地区文化和社会经济因素的联系（GDE 在支持生物多样性和农村生计方面发挥着重要作用），以探索在政治不稳定地区保护 GDE 的其他方法。我们的 GDE 地图提供了关键信息，用于在不同地方、区域或国际范围内确定优先顺序并制定政策和保护机制，以保护这些重要的生态系统和依赖它们的社会。