Valentí Rull, Isaac Casanovas-Vilar, Alba Vicente

During the Miocene Climatic Optimum (MCO; 17–15 Ma), the northern boundary of mangroves – now situated at ~30° N – extended along the northern Mediterranean coasts (~45° N). These Avicennia-only mangroves have been considered impoverished mangroves controlled by the general latitudinal temperature gradient. The MCO Mediterranean mangroves have been compared with the extant Middle East (ME) mangroves around the Arabian Peninsula, characterized by the dominance of Avicennia and their low diversity. However, these extant communities are not a latitudinal feature but rather an anomaly shaped by extreme environmental conditions (aridity, hypersalinity, sediment supply) that only a few mangrove species can tolerate. In contrast, reconstructed environments for MCO Mediterranean mangroves indicate mild, rainy climates. We conclude that current ME mangroves cannot be considered modern analogs for the MCO Mediterranean mangroves. Finding such modern analogs is challenging, and further studies are recommended to uncover their ecological and biogeographical patterns.