Vulnerability of mangroves to climate change

Abstract

Mangroves are valuable coastal resources in the Asia-Pacific region, providing protection against the impacts of wind and wave energy, construction wood, and promotion of better water quality. Fishery products derived from mangroves provide local communities with a large proportion of their daily protein intake. However, mangroves are among the most impacted ecosystems of all, with many countries in the region having lost 50% of their mangroves in the last 20 years, degraded and converted to other uses. Mangrove ecosystems are also vulnerable to climate change impacts, particularly sea-level rise. Inter-tidal mangrove forests occur on low gradient sedimentary shorelines, where if inundation period increases then forest health, productivity and recruitment are affected. This may be exacerbated by the wind and wave impacts of extreme storms. Increased air and sea temperatures along with enhanced atmospheric carbon dioxide may alter processes in mangroves of respiration, photosynthesis and forest productivity. Changes in rainfall and humidity affect processes of sediment inputs, groundwater and salinity, and result in changed productivity and sediment elevation. The response of mangrove habitats in different coastal locations to climate change impacts is subject to factors of coastal behaviour, such as mangrove community composition, site tidal range, salinity regime, sedimentology and shore profile. Vulnerability assessment of climate change impacts can provide site-specific synthesis of these different factors, and allow appropriate adaptation actions to be prioritised.