July 26th marks the International Day for the Conservation of the Mangrove Ecosystem.

The mangrove ecosystem, a unique and precious ecosystem

An ecosystem is a habitat made up of a non-living environment and all the living organisms that inhabit it, feed on it and reproduce in it. Mangroves are ecosystems that provide important services for coastal protection. They act as nurseries as well as growth and feeding grounds for many marine species. Thus, they play a major role in the preservation of biodiversity. Mangroves are able to filter and retain pollutants before they are released into the sea. They attenuate the energy of the waves, preserving natural and inhabited coastal areas. They protect and stabilise the coastline against rising sea levels and violent weather events such as cyclones. A mangrove is also a carbon sink as it stores carbon and therefore helps regulating global climate.

Nevertheless, these ecosystems are facing increasing pressure from both natural and human activities.

Increasing pressures from extreme weather events

Cyclones are the main mortality factor for the typical mangrove trees. In addition, cyclones, tsunamis and droughts (increased aridity, salinity and acidity of the soil) can cause fragility.

Climate change results in an increase in the frequency and intensity of extreme weather events such as cyclones and droughts, which may have an even greater impact on mangroves.

Increasing anthropogenic pressures

Regarding anthropogenic pressures, the main sources of mangrove damage are urban development, tourism, agriculture, aquaculture (shrimp farming), overexploitation (wood, fish) as well as modifications to upstream waterways (dams, diversion, water withdrawal, irrigation, riverbank development, etc.).

Mangroves are the downstream catchment area of watersheds. Consequently, they receive water pollution from communities, industry and agricultural activities. They are sometimes used as illegal dumps. This pollution has considerable effects on the functioning and biodiversity of mangroves. They can even lead to chronic poisoning of the fauna and flora.

In some cases, the tidal flow and biological processes of mangrove components can act as natural filters by absorbing and transforming pollutants. However, the thresholds at which toxicity becomes damaging are not well known.

Therefore, wastewater treatment is fundamental to limit the pollution of natural ecosystems such as mangroves and to preserve them from pressures that threaten their conservation.

For more information: http://ifrecor-doc.fr/items/show/1481