Unravelling a Maldivian mangrove mystery

Cusat researchers uncover causes of Maldives mangrove dieback

Researchers at the Cochin University of Science and Technology (Cusat) have helped the Maldivian government unravel the alarming mystery behind a mass dieback of mangroves reported in the archipelagic nation during March 2020 and March 2021.

Their findings, published in the Springer journal Regional Environmental Change, point to climatic factors and localised sea level changes as the key drivers behind the phenomenon that primarily affected the Bruguiera cylindrica, a mangrove species that holds cultural and historical significance for the local communities.

As the term implies, ‘dieback’ is a condition where a plant begins to die from the tip downwards.

Cusat collaborated with the Environmental Protection Agency, Maldives, for the study under a joint India-Maldives research programme coordinated by the Indian High Commission in Male.

According to the paper - ‘Distribution, drivers, and community perceptions of recent mass mangrove dieback in Maldives’ - soil salinity caused by higher temperatures, prolonged drought linked to the triple La Nina phenomenon and positive Indian Ocean Dipole and localised sea level changes triggered the dieback event.

Large-scale dieback of Bruguiera cylindrica, a species that grows to a height of ten to 15 metres or more, had been observed since March 2020. The phenomenon threatened the nation’s ecology, livelihood and socio-economic stability, the paper notes.

Mangroves are found on at least 150 of the 1,190 islands in the archipelago. These islands are low-lying and hence, vulnerable to sea level rise and climate change. The present study covered islands that were experiencing the phenomenon, all of them situated less than one metre above sea level. A socio-ecological survey revealed that the dieback disrupted livelihoods as the island population depends on the mangrove ecosystem for food, timber for boat construction, coir making as well as spiritual and recreational pursuits.