A dwindling prey base due to shrinking grazing lands is affecting the big cat population in areas where the toxic lantana weed runs riot

A report quoting a recent study that the tiger population in the Mudumalai Tiger Reserve in Tamil Nadu is facing threat because of the rapid growth of the lantana plant has brought to the fore the havoc this invasive species is causing to the biodiversity across the tropical and sub tropical regions of our country. The tiger population, the report warned, will dwindle drastically within the next five years, unless the plant is removed from the forest.

Lantana spreads very fast and does not allow anything else, including grass or other plant or shrub, grow in the area leading to the migration or decline in the number of herbivores. This can lead to starvation of tigers, leopards and other carnivores at the top of the food chain.

Poisoning incidents

Also, the foliage and ripe berries of the lantana plant contain toxic substances, which affect cattle, sheep, horses, dogs, guinea pigs, and rabbits. In fact, India is one of the countries from where incidence of lantana poisoning has been reported regularly, both sporadic cases round the year to heavy outbreaks during drought or floods when the fodder becomes scarce.

Not just the Mudumalai Tiger Reserve, even the Nagarahole National Park and Bandipur National Park in neighbouring Karnataka and the Jim Corbett National Park in Uttarakhand are amongst the worst-hit by the spread of this flowery shrub.

The Corbett Tiger Reserve (CTR) adopted the Root Cut Stock methodology about a decade back to treat areas encroached by lantana. Deputy Director of Corbett Tiger Reserve, Saket Badola, said the methodology is proving to be effective in efforts to eradicate this species. He explained that areas cleared of lantana are followed up for three years and grass palatable for the herbivores is grown. Lantana grows in about 30 to 35 per cent of the CTR area.

First introduced in India in 1807, lantana has spread from the Himalayas to the southernmost parts of the country, though it is the hilly regions, especially the Shivaliks that have largely borne the brunt of the spread of this species.

Livelihoods impacted

In Himachal Pradesh, the fast spread of lantana is adversely impacting not only wildlife, cattle, medicinal and other native plant species but also affecting the livelihoods of a large number of local people, including the tribal population. The districts of Mandi, Hamirpur and Solan are the worst affected.

According to Anil Vaidya, Conservator Forests, (CAT plan) Shimla, the growth of native species like bule, kachnar, ohi and kamal have been affected by lantana. With lantana encroaching pastures and grazing area and impacting the productivity of the soil, it has caused widespread loss to livelihood.

Yet another problem is that when carnivores like leopards do not find food in the forests, they tend to move into human habitations causing human-animal conflict. As one of the forest officials pointed out, the sighting of chital, Indian Gaur, spotted deer, sambar and other wild animals have become rare in some of the wildlife sanctuaries encroached by lantana.

In the Shivalik foothills of Jammu and Kashmir also the lantana shrub has been making inroads into pastures, thereby shrinking the areas for cattle grazing and like Himachal Pradesh, affecting the livelihood of people.

The ‘Cut Root Stock’ methodology is now being implemented in Himachal Pradesh with certain modifications according to climatic conditions of the State. Hitender Sharma, Assistant Conservator of Forest, Solan Forest Division, said that after the removal of lantana from many areas in the Solan forest division, local grasses and flora have come up very well. He added that this method results in permanent removal of lantana, is cost-effective and has minimum impact on the soil.

Control the spread

For Himachal Pradesh, where over 177,000 hectares of forest and other land have been encroached by lantana, the priority is to control the speed of the spread of this weed, pointed out Mr. Vaidya. According to the latest data available, a little over 8,776 hectares of land infested by lantana in the State has been treated and the target fixed for the current financial year is 5,000 hectares.

For wildlife experts and authorities, besides tackling the problem of poaching, the challenge today is to urgently control the voracious hunger for growth of lantana that is indirectly threatening the population of the big cats, local flora and fauna as well as causing serious livelihood problems.