A new technology called ‘Bio-restoration’ developed by Indian scientists for ecological restoration is helping in revival of mangroves degraded due to rising sea levels, climate change and human intrusion in the Sunderbans in West Bengal. The Bio-restoration of Sunderbans involves plantation of native salt-tolerant grasses and a diverse set of carefully identified mangrove species in different zones of degraded mangrove patches. It also involves the use of growth-promoting bacteria.
Ecological restoration means reviving native ecosystem in degraded areas. This has to be done while maintaining diversity of original flora and fauna through regeneration but bringing down the regeneration period to four-five. Natural regeneration takes longer time.
The Sundarbans is a protected wetland under the Ramsar Convention and is also a Unesco World Heritage site. Small coastal patches of mangroves are highly vulnerable and fragmentation of the ecosystem is creating barriers to species movement and dispersal. Bio-restoration of Sunderbans, therefore, is an effective method of ecological restoration and the need of the hour.
The restoration process begins with stabilising entire site of restoration by planting native salt tolerant grasses. An onsite mangrove nursery was developed to propagate mangroves for transplantation. Besides local mangroves and associate species, the nursery also grew thretened, endangered and vulnerable species. In all, 22 species of mangroves and associate plants were grown so as to maintain native diversity.
The transplantation started in November 2014, initially at a moderately degraded patch and was then extended to severely degraded zones.