Global mangrove distribution on the open coast is controlled by waves

Mangrove forests are ecologically important ecosystems that provide services such as coastal protection¹ and climate change mitigation². Understanding why mangroves are present at a location can provide causal links for mangrove management, restoration science³ and climate change adaptation. On the open coast, the influence of waves in shaping mangrove distribution is poorly understood. Here we show that waves are a key control on global coastal mangrove distribution. We developed a process-driven mangrove presence or absence model to assess 20 years of open-source hindcast wave data including three swell partitions at 400 globally distributed coastal sites. By defining and identifying windows of opportunity for mangrove establishment in cases for which wave forcing is low, the mechanistic model achieved 78.2% accuracy. Modest increases or decreases in wave forcing affect the suitability of mangrove sites, demonstrating that future region-specific changes to wave climate may lead to distributional shifts along the coast. Waves are a primary control on open-coast mangroves globally and this knowledge is essential to predict current and future mangrove distributions in a changing climate.