Triple trouble for Gulf of Mannar islands, study finds 

An invasive plant from South America is threatening to pulverise indigenous plants across the 21 islands of Gulf of Mannar where 96 species of birds have been recorded.

An alien invasive plant is threatening to pulverise native vegetation across 21 islands in the Gulf of Mannar Biosphere Reserve (GoMBR), an avian distribution study has revealed. 

Prosopis chilensis, a drought-resistant plant native to the arid regions of four South American countries — Argentina, Bolivia, Chile, and Peru — is not the only trouble for these islands divided into the Tuticorin, Vembar, Kilakkarai, and Mandapam groups. 

The coral reef has been destroyed in several places near these islands although coral quarrying for industrial purposes has been outlawed, the study published in the Journal of Threatened Taxa said. 

Human settlements, though not permanent, have also impacted the islands such as Poomarichan, Pullivasa, and Manoliputti in the Mandapam group, the study said, while recording 96 species of birds on these islands. 

The authors of the study are H. Byju and S. Ravichandran of Annamalai University’s Centre of Advanced Study in Marine Biology, and N. Raveendran of the Madurai-based Iragukal Amritha Nature Trust. 

“Most of the islands have sand dunes along their coastlines with salt-dominant plant species. Some of the islands contain trees while the marshy sections of some of the islands are occupied by mangroves and allied species,” Dr. Byju told  The Hindu. 

“We found the  Prosopis chilensis in seven or eight islands. Any invasive species on an island will slowly kill the native trees as well as the mangroves as we have seen some overgrown to the edge of the islands near the high tide areas,” he said.