For over a century, like an expansionist coloniser it gobbled up hundreds of acres of our land, meticulously killing one plant species after another, starving them of nutrition and water. But, not any more. Freedom is in sight.
An army of scientists, now backed by a special budgetary support of Rs 50 lakh from the Delhi government, are reclaiming the land by rooting out the Vilayti Kikar from Delhi.
The Kikar (Prosopis julifora) was brought to Delhi from Mexico by the British more than a century ago. The exotic plant became invasive and wiped out most of the native plants and along with it the animals, which once used to roam in the ridges. It had also wreaked havoc on city’s groundwater.
Scientists have got initial successes in Aravalli Biodiversity Park (ABP) and in a small portion of Yamuna Biodiversity Park (YBP). Their next target is the ridge.
“You can say it is a kind of ecological succession. We are replacing the Vilayti Kikar with native plants. We have got initial success in both Yamuna Biodiversity Park (YBP) and the Aravalli Biodiversity Park (ABP). Now we are targeting the ridge from where want to replace the Kikar from around 800 acres in a phased manner,” said CR Babu professor emeritus at Centre for Environmental Management of Degraded Ecosystems in Delhi University.
In both the parks, where Kikar scared away all the native plant species away, the scenario has changed. While large swathes of forests which were once monopolised by the Kikar in Aravalli and Yamuna biodiversity park a few years ago, have now been reclaimed with the help of native species.
Full grown plants of Kulu, Salai, Dhau, Dhak and Inderjau among other that had almost vanished because of the Kikar are now back in the Aravalli and Yamuna biodiversity parks. The forests now seem livelier with several canopy layers rather than just a monotonous plantation of Kikar.
“We have replaced the kikar with around 900 native species, including grasses, over 400 acres in ABP. Around 30 different forest communities, each community comprising 10 – 30 different plant species, have come up in the park,” said M Shah Hussain scientist in-charge of ABP.
The native plants are also helping the animals that had once abandoned these areas to come back too. The count of bird species in Aravalli have also shot up from 50 in 2004 to more than 200 now. Some birds such as the black eagle, Indian pitta and pied hornbill have been spotted after almost seven decades.
The Kikar (Prosopis julifora) was brought to Delhi from Mexico by the British more than a century ago. The exotic plant became invasive and wiped out most of the native plants and along with it the animals, which once used to roam in the ridges
■ Anogeissus pendula (Dhaura) ■ Sterculia urens (Kulu) ■ Acacia leucophloea (Ronjh) ■ Wrightia tinctoria (Sweet inderjau) ■ Prosopis cineraria (Sami)
■ Mitragyna Parviflora (Kaim) ■ Syzygium heymaneum (Kathjamuni) ■ Dalbergia sissoo (Shisham) ■ Kydia calycina (Bharanga) ■ Acacia catechu (Khair)
In the Yamuna park, the butterfly population has shot up from just two species in 2002 to more than 75 now. While dung pellets and hoof marks of herbivores animals on the forest floor signal the return of animals such as boars and nilgai, recently a leopard was also spotted.
But the task of bringing back native species was easier said than done. Scientists had to survey the Aravalli ranges in neighbouring states such as Gujarat, Rajasthan and Madhya Pradesh to identify suitable plants. Nurseries in those states were requested to send seeds and saplings of wild plants.
“These saplings were nurtured in our own nurseries till they were at least 4-5feet tall. Only then we planted them in the forest to challenge the Kikar. Regular watering and cow dung manure was given at least for the following two years so that the natives could fight the foreigner,” said Faiyaz A Khudsar, scientist in-charge of the Yamuna Biodiversity Park.
Then, it was time for the final assault.
Scientists opened up the thick Kikar’s canopy by trimming the branches so that sunlight could reach the saplings of native species.
The strategy worked. The native species being taller than Kikar were able to cut off sunlight from reaching the Kikar when they were fully grown. Without sunlight the Kikar failed to produce food and started to wither.
Prabhakar Rao, one of the core members of Kalpavriksh, an NGO, said that the approach taken by Babu and his team seemed to be correct as trees like the Kikar need a lot of sunshine. “Once the native trees grow taller and create a shade over them, the Kikar died,” he said.
Scientists are now ready to take on the Kikars at Kamala Nehru ridge (northern ridge). Saplings are being made ready so that they could be planted with the arrival of the monsoon this year. The first assault would be launched on an area of 50 acres.
Knee-height saplings of native plants could be seen waiting in long rows at the Kamla Nehru ridge to take on the notorious foreigner this monsoon. Labourers have been deployed to nurture them every day.
But not all experts agree with this ‘replacement’ method. They claim that the Kikar releases toxins which make the soil almost unfit for other species and the only solution is to uproot the tree.
“The Kikar’s roots secrete a kind of toxin (an alkaloid) which inhibits the growth of other plants. It was because of this that most native trees vanished. Only a few plants such as the Kanju can withstand this toxin but most plants can’t. Just planting a native tree and allowing sunlight doesn’t help. It has to be uprooted from at least 30 inches deep in the ground,” said Pradip Krishen, naturalist and author of the book, Trees of Delhi. He has been working on Kikars in Jodhpur for quite long.
Amid all this, a ruling by the Madras High Court has further boosted the zeal of the scientists. The court suggested that the Tamil Nadu government should bring a special act to eradicate Prosopis juliflora, which has damaged native plant species in the southern state.
Scientists are also planning to approach the Delhi government’s environment and forest department so that the action plan could be taken up in other areas in Delhi.