Mangrove forests are becoming increasingly vulnerable, owing to the impoverishment in biodiversity of the invertebrate fauna that colonise these ecosystems and carries out essential ecological functions for their survival. This is the alarm launched by an international study coordinated by Stefano Cannicci and Sara Fratini, researchers at the University of Florence and published in PNAS precisely on UNESCO’s International Mangrove Day.
The research project has recorded the lowest frequency of biodiversity in species of resident invertebrates – mainly crabs and molluscs – living in mangrove forests stretching across South America, the East Indian Ocean, and the Pacific. These coastal forests are already threatened by deforestation eroding their extension.
Researchers mapped 209 species of crustaceans and 155 species of molluscs in 16 tropical and subtropical forests around the world. They then classified these species into 64 functional entities - based on what they eat, their behaviour and the specific microhabitat in which they live - essential for the viability of the mangroves.
“Mangroves are very important for an array of ecosystem services they provide to local communities, starting from carbon sequestration, and therefore from the reduction of the effects of climate change” says Stefano Cannicci, full professor of Zoology at Unifi. "These forests colonise the areas of the shore flooded by tides -harsh environments, due to the salinity of the water and the lack of oxygen present in the soil," the researcher explains. "Invertebrates come to their help, constantly moving the soil to feed and build their burrows and ultimately increasing the natural cycle of nutrients, which become readily available for the plants, and providing oxygen to the roots.”
Scientists have found that there are only one or just a few species performing similar functions in many of our planet’s mangroves, and they have identified the forests that could suffer the greatest damage from faunal impoverishment.
“Our data tell us that even a modest loss of biodiversity of invertebrates can have negative consequences on the functionality and resilience of mangroves to environmental changes, particularly climate change, but there are still areas that will be a valuable biodiversity reservoir for these forests,” comments Sara Fratini, Assistant Professor in Zoology.