// NATURE NEWS — SPAZIO & SCIENZA
Global mangrove distribution on the open coast is controlled by waves
Nature
(2026) Cite this article
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.
There is a growing global effort towards coastal ecosystem restoration and conservation, with the United Nations Decade on Ecosystem Restoration and the Decade on Ocean Science for Sustainable Development under way. As conservation initiatives expand in response to historical habitat declines and reduce human-driven rates of deforestation4, environmental drivers are accounting for an increasing portion of mangrove loss relative to land conversion5. This indicates that, although managing direct anthropogenic mangrove loss is a continuing endeavour, understanding and predicting future natural dynamics is an important consideration for mangrove conservation.
Mangroves face an uncertain future because many locations are vulnerable to sea-level rise and shifting weather and climate patterns6,7,8. Mangroves occurring along open, wave-exposed coasts are of particular interest because they provide unique benefits to adjacent ecosystems and communities, with coastal protection being the second most studied ecosystem service of mangroves9. Open-coast mangroves are uniquely susceptible to changes in wave climate, for which changes are projected to be dominated by shifts in wave direction by 5°–10° throughout tropical and extra-tropical regions10, as well as potential region-specific changes in storm frequency11.
Mature mangrove forests are influenced by the local physical environment and influence the surrounding hydrodynamics through wave attenuation1,12. However, during the seedling establishment stage the environmental relationship is unidirectional13,14, with hydrodynamics being one of the key bottlenecks to propagule anchoring and establishment. During this establishment phase, the buoyant propagules of mangrove pioneer species such as Avicennia alba need to anchor quickly to avoid dislodgement15. Early approaches to modelling mangrove distribution relied on correlating mangrove presence to time-averaged inundation values such as hydroperiod16. However, this approach does not consider the distinct events leading to establishment or mortality and is limited in environments with strong seasonality. It has been shown that in estuarine environments with different tidal regimes, this approach can lead to inaccurate predictions of extent17. These limitations have been addressed in recent approaches17,18,19,20, which use a process-driven approach involving windows of opportunity (WOOs) for mangrove establishment. WOOs are defined as periods in which conditions do not exceed thresholds for seedling survival. These thresholds vary with seedling age because their vulnerability decreases as seedlings mature19 (Fig. 1).
Concept of the increasing tolerance of mangrove seedlings to wave forcing as t