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After clearing the Pallikaranai marshland of the invasive seema karuvelam species (Prosopis juliflora), a garden with saplings of native fruit-bearing species was set up by four months ago by the state forest department. The saplings are now healthy and one-metre tall, said forest officials.

The alien plant species covered more than 3.25 hectares of the marshland spreading over 695 across hectares and proved a hindrance to the authorities in taking up development work. Environmentalists are pleased that the sensitive marshland has been reclaimed from the danger posed by such species.

Co-founder of Care Earth Trust, a biodiversity research organisation, Jayashree Vencatesan, said managing invasive alien species calls for nuanced understanding of ecosystem. “In a marsh such as Pallikaranai, when an invasive species is changing its habitat, it is fallacious to say that birds are seen perching on the plant”. In critical and fragile habitats, invasive species can cause irreparable damage, she added.

“Invasive plants grow rapidly with their roots penetrating deep into the soil, depleting the water content. So clearing them is the only option,” said Ranjit Daniels, a biodiversity researcher. Moreover, such invasive species form a mat-like structure on the soil surface around them, discouraging growth of other species, he added.

The saplings planted include those of Iluppai, Naaval, Neer marudhu, Kodukkapulli, Neer Kadambu, Atthi, Pala, Vembu and Pungan. These native species are fruit-bearing, and known to attract a large number of birds. The garden is well-barricaded to avoid cattle grazing on the new plants and is watered twice a day.

The environmentally fragile marshland which not too long ago was spread more than 7,000 heactares has now been reduced to a mere 700-odd heactares. The wetland is crucial to the ecosystem of the region, say conservationists.

Source: Times of India, 13, April, 2019, Chennai.