Most of the wetland ecosystems in the city of Coimbatore are populated with the Karuvelam tree known as Babool. This species has particularly found mention in wetland restoration activities in the south of our country. The Seemai Karuvelam tree, or prosopis juliflora as it’s known biologically, is a species native to West Africa and was introduced in India by the Britishers to meet the increasing need for charcoal. They grow well in dry regions where rainfall was less than 200 mm. The tree was brought to Tamil Nadu in the 1960s as fuelwood. Slowly, these seeds started drifting into dams and rivers, causing problems. The plant according to multiple reports, absorbs excess ground water, adding to the woes of the water- starved state. Several drives have been organised for the eradication of these trees from wetland and dryland ecosystems owing to its negative impacts on the water table and its ability to prevent other natural growth around it. Over the years studies have brought to us the positive and negative effects of this species. A large portion of the rural population in TN depends on the trees for their livelihood. The trees have traditionally been extensively used as fuel wood, charcoal. It is a major boon for impoverished people subsisting in those environments as it provides them with badly needed shelter, reduces erosion, improves micrometeorology, and is a source of food, feed, fuel, medicines and cosmetics.
However, it can prove to be toxic to other biota in ways that allow the invasives to monopolise space and nutrients at the exclusion of other species and this leads to a decline in the proportion of indigenous woody species. The thickets also provide breeding grounds for mosquitoes, causing an increase in the incidence of malaria. It is clear that keeping the population of Karuvelam under control is crucial to maintain biodiversity by allowing for native species to establish themselves. However an attempt to completely eradicate this species holds strong implications for the lower sections of society and particular wetland species that have evolved to grow dependent on these trees for shelter and breeding grounds. It is important to understand it’s never possible to restore an ecosystem to its previous state but we need to rethink the role of such invasive species in light of the equity question and changing requirements for maintaining the stability of ecosystems.
By
Trrishala Kumarswamy
Lakes of India 