October 31, 2018
Alien plants, introduced mostly by the British, have proliferated across the Western Ghats. The second worst threat is the biological invasion of ‘alien species’, according to the Convention for Biological Diversity. Their effects on biodiversity are on a large scale and often irreversible.
The Madurai Bench of Madras High Court, hearing a public interest litigation petition, ordered removal of invasive trees and directed the National Board for Wildlife to look into the issue and pass appropriate orders.
The word alien refers to species that have been introduced to the region outside their origin. Intentionally or unintentionally people move species like crops, fruits, fibres to a different region. The subset of this introduced species is problematic. The fraction of these ‘alien Species’ (AS) contributes to the demise of native ones. Alien species, after becoming locally dominant, invade natural communities and become Invasive Alien Species which causes a major challenge at a global level.
The study of alien plants on community structure and their role in our ecosystem processes are poorly understood here. Invasive species intervene in the functioning of ecosystems and negatively affect the flora and fauna, some of the impacts which we have faced are flood control, water supply, water assimilation, nutrient cycling, conservation and regeneration of soils, it is pointed out.
The Nilgiris upper slope has been invaded the flora like eucalyptus, wattle, pine and cypress, as well as lantana camara plants, while on the biosphere’s lower slope, prosopis juliflora, parthenium and eupatorium can be found, forest officials said.
The scrubbing method adopted by all national parks and their adjoining areas of Western Ghats can contribute more to structure a framework for the consideration of invasive species in ecological restoration. All planned disturbances and restoration projects should consider the surrounding landscape and existing situation and recognise that biotic exchange will occur with the management site, says field botanist, Dr S Rajan.
Restoration efforts should happen at a small scale but simultaneously at various national parks like Bandipur in Karnataka, Muthanga Wildlife Sanctuary in Kerala and Mudumalai in the Nilgiris for facilitating native species grow and thrive in their habitat. The department needs funds, proper execution, manpower and persistence, he added.
It is a humongous task and can not be executed by only one agency. With the collective effort of government, agencies, various government and non-governmental research institutes and universities one can tackle the issue of invasive species.