Why in news? Prosopis chilensis, an alien invasive plant is threatening to pulverise native vegetation across 21 islands in the Gulf of Mannar Biosphere Reserve (GoMBR), as revealed by  an avian distribution study.

Highlights:

• It source of trouble for 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
• 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

About Gulf of Mannar Biosphere Reserve

• The Gulf of Mannar is a large shallow bay forming part of the Laccadive Sea in the Indian Ocean.
• It lies between the southeastern tip of India and the west coast of Sri Lanka, in the Coromandel Coast region.
• The chain of low islands and reefs known as Ram Sethu (aka Adam’s Bridge),that includes Mannar Island, separates the Gulf of Mannar from Palk Bay, which lies to the north between India and Sri Lanka.
• The estuaries of Thamirabarani River and Vaippar River of South India and the Malvathu Oya (Malvathu River) of Sri Lanka drain into the Gulf.
• The dugong (sea cow) is found here.
• The GoMBR, India’s first marine biosphere reserve, is one of the important habitats for coastal birds migrating as far as the Arctic Circle.
• The area is of particular significance as the 21 islands also serve as resting places for birds migrating to and from the nearby Sri Lankan islands.

About Prosopis chilensis:

• The Prosopis chilensis is also known as Chilean mesquite.
• It is a small to medium-sized legume tree that grows up to 12 m in height and 1 m in diameter.
• It is a drought-resistant plant native to the arid regions of four South American countries namely Argentina, Bolivia, Chile, and Peru.