Mangroves are one of the few woody ecosystems that grow in hot-arid climates. They can survive extreme conditions of low precipitation, high solar radiation, wide temperature fluctuations and hypersalinity. These unique mangroves have distinct geomorphology, hydrology, forest structure, tree physiology, and soil biogeochemistry. In this review, supported by field data from Australia and Mexico, we explore the characteristics of mangroves in arid climates of the world. These mangroves are mostly tide-dominated with freshwater flows restricted to groundwater and sporadic tropical storms. They form dense forests with stunted growth dominated mainly by trees of the genus Avicennia that co-occur with salt marshes in the high intertidal. Their soils have low nutrient and carbon concentrations, and high soil δ15 N and δ13C values compared to subhumid and humid mangroves. Mangroves in arid climates have relatively low human pressure due to sparse human settlements. Key threats to these mangroves, which often persist at the edge of their physiological tolerances, include extreme drought, reductions in groundwater inputs, altered hydrology, sea-level fluctuations and increases in nutrient loading. Restoration of mangroves in arid climates should focus on restoring their hydrology. Mangroves in arid zones are under-represented in global maps and assessment programs, as they may not be consistent with countries’ definition of “forests”. Improved global representation and understanding of the ecology of mangroves in arid climates could help sustain their valuable ecosystem services.

红树林是在炎热气候下生长的少数木质生态系统之一。它们可以在低降水，高太阳辐射，宽温度波动和高盐度的极端条件下生存。这些独特的红树林具有独特的地貌，水文，森林结构，树木生理学和土壤生物地球化学。在这篇综述中，在澳大利亚和墨西哥的实地数据的支持下，我们探索了世界干旱气候下的红树林特征。这些红树林主要由潮汐控制，淡水流量仅限于地下水和零星的热带风暴。它们形成生长茂密的森林，生长发育迟缓，主要是Avicennia属的树木在潮间带高潮时与盐沼共同发生。与半湿润和湿润的红树林相比，它们的土壤营养和碳含量低，土壤δ15N和δ13C值高。由于稀疏的人类住区，干旱气候中的红树林具有相对较低的人类压力。对这些红树林的主要威胁经常在其生理耐受力的边缘持续存在，包括极端干旱，地下水输入量减少，水文学改变，海平面波动和养分含量增加。在干旱气候下恢复红树林应集中精力恢复其水文状况。干旱地区的红树林在全球地图和评估计划中的代表性不足，因为它们可能与各国对“森林”的定义不一致。