6. Bioinvasion and Environmental Perturbation: Synergistic Impact on Coastal–Mangrove Ecosystems of West Bengal, India

Numerous ideas have emerged on the definitions, consequences of introduction, causes of damage, population dynamics and mode of propagation, prevention, and adaptibility of invasive species along with their impact on native species directly or indirectly by way of alteration of ecosystem dynamics. An Invasive species is defined as a species having been introduced outside its native range through human activities which are likely to cause economic or ecological harm. Estuaries and Coastal-Estuarine –Mangrove ecosystems being the most productive and sensitive ecosystems in the world, have appeared to be very much susceptible to introductions of non-native species because of lot of possibilities out of different ecological and people oriented activities in and around these eco-regions such as shipping and boating, ecotourism, fisheries, aquaculture etc. Alongside, several ecological perturbations such as eutrophication, global warming, biomagnification and biotransformation of persistent pollutants, etc. along with the negative impacts of introduced species on marine estuarine flora and fauna by outcompeting them for basic life support resources, human health risk associated with transmission of pathogens, and higher bioaccumulation capabilities of invasive species than native species have threatened this ecologically sensitive region considerably.

This book chapter aims at highlighting the prospective consequences of the bioinvasion on the coastal–estuarine networks of West Bengal, India which is unique because of the presence of more than hundred of deltas endowed with world’s largest mangrove chunk and associated flora and fauna giving emphasis on ecosystem processes and functions. In view of the different threats as imposed by invasive species on native ones, even leading to their extinction, proper holistic eco-management strategies are being suggested giving emphasis on the self-sustaining ecosystem functioning of coastal- estuarine -mangrove ecosystem where species do not inevitably spread rapidly and extensively beyond control.