Is casuarina (casuarinaequisetifoiia) of the coastal belt in Batticaloa, Sri Lanka, invading the sea front beach?

Abstract

The evergreen conifer-like angiosperm Casuarinaequisetifolia, a native of Australia, is introduced for coastal protection and other reasons and is naturalized throughout the tropics. About 450 ha (about 35-40% of the coastline of the Batticaloa district) have been planted in the north-east Sri Lanka after the year 2000. C. equisetifolia is a highly invasive plant which has been listed in the "Global Invasive Species List' and has become an invasive weed in many countries where it has been introduced. It readily disperses by windblown seeds and also by suckering (rooting along branches that touch the ground). This study was carried out to investigate the invasion by C. equisetifolia of the coastal belt of Batticaloa. A rapid assessment using eye observation for invasion by seeds and by suckering was carried out at three sites: Ondachchimadam North, Ondachchimadam South and Periyakallar. Although no evidence of spread by seeds was found the sea front beach was found to be invaded by suckering to different extents in different sites. This may be favorable in terms of coastal protection but the effect on the natural biodiversity, ecology and socioeconomic activities may be negative.