Mangrove forests: Resilience, protection from tsunamis, and responses to global climate change
This review assesses the degree of resilience of mangrove forests to large, infrequent disturbance (tsunamis) and their role in coastal protection, and to chronic disturbance events (climate change) and the future of mangroves in the face of global change. From a geological perspective, mangroves come and go at considerable speed, having undergone almost chronic disturbance as a result of fluctuations in sea-level. Mangroves have demonstrated considerable resilience over timescales commensurate with shoreline evolution; soil accretion rates in mangrove forests are currently keeping pace with mean sea-level rise and mangroves display pioneer-like responses to natural disturbances.
research goals & methods
The effects of mangrove stand composition on tsunami protection are not fully understood. Stand composition are the result of a complex interplay of physiological tolerances and competitive interactions leading to a mosaic of interrupted or arrested succession sequences, in response to physical/chemical gradients and landform changes. Mangroves may offer limited protection from tsunamis; some models using realistic forest variables suggest significant reduction in tsunami wave flow pressure for forests at least 100 m in width. The magnitude of energy absorption strongly depends on tree density, stem and root diameter, shore slope, bathymetry, spectral characteristics of incident waves, and tidal stage upon entering the forest.
conclusions & takeaways
Concern has been raised about the impacts of climate change and sea level rise on mangrove forests. Other authors have estimated a 10-15% overall global loss in mangrove forests as a result of climate change. However, the current annual average rate of deforestation already stands at 1-2%. Taken over many years, this represents a major loss in mangrove forests.
Mangrove forests: Resilience, protection from tsunamis, and responses to global climate change. Estuarine, Coastal and Shelf Science. 2008;76:1–13. doi:10.1016/j.ecss.2007.08.024..
- Australian Institute of Marine Science, Queensland, Australia