Introduced For Its Firewood, Prosopis Julifera Has Destroyed Native Species
Invasion by kings and rulers from foreign lands may have been in the past. Today's ma rauders can be equally destructive -but they are in the form of plants, weed and trees. They systematically destroy local or endemic species and wreak havoc on natural resources including waterbodies.
One such weed is Prosopis juliflora, a native of South and Central America, which was introduced during the British regime in India nearly 150 years ago. Those days the plant was considered an excellent alternative for fuel wood. It could be used to make charcoal and wheels of bullock carts in other words, it was considered a boon for rural masses. The weed was planted without understanding how it could destroy our natural resources, said a senior forest officer.
Originally the social forestry wing of the department planted babul, a known local species (Acacia nilotica). The branches of these trees are used as nesting and roosting sites by migratory birds. But, this species was slowly overpowered by the Prosopis in several parts of the state, dominating the vegetation in waterbodies, the officer said.
What made matters worse was that the traditional maintenance work that people used to take up in w a t e r bodies l i k e yearly cleaning of the bund and desilting had stopped, says as sociate professor at the department of Botany in Madras Christian College D Narasimhan. This was a big boost for the invasive species they could proliferate and destroy local species, he said.
Mere uprooting will not be the solution to the problem of invasive species, he says. The authorities should ensure that the uprooted invasive plant does not regenerate in the waterbody or on its bund.And the old system of planting local species along the bund should be revived, says Narasimhan.
The thriving Prosopis not only killed local species of trees, herbs and shrubs, but also depleted the groundwater table drastically . It flourishes because its roots are known to go deep underground and suck out the water.
These invasive species are firehardy and can withstand adverse climatic conditions and thrive, ex perts say . Soon they would make the waterbodies they have invaded go dry even before the beginning of the dry season, they add.
Prosopis is so alien that cattle that feeds on it becomes infertile, says Selvam Ramaswamy of Wake up Madurai, a Madurai-based group fighting against the weed.The organization is in the process of educating students and villages about it.
Paulin Deborah of Botany department, Women's Christian College said: “These plants not only colonize wastelands and poromboke lands but also waterbodies.For example in Adyar river, they posed a major threat to the very survival of a small patch of mangroves behind the Theosophical Society. Here one could see the Prosopis interspersed with the Mangrove species, Avicennia.“
Similarly, a small patch of mangroves on Swami Sivananda Salai, behind the Madras University Campus, has completely disappeared. Prosopis has taken over. “It is important to first survey which areas are under threat and take measures to clear the weed,“ said Deborah.
With pressure from farmers across the state and land under the custody of Public Works Department, it is high time the government takes a decision to eradicate this invasive species that's grown in our water bodies. Otherwise the fight against water scarcity would become tougher, warn naturalists.
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