Predators will die of starvation if herbivores are affected

Tiger population in Mudumalai Tiger Reserve (MTR) in The Nilgiris that has survived against all odds over the years is facing a queer threat now.

Lantana, a major invasive alien plant species is likely to wreak havoc if no serious effort is made to clear it on a long-term basis.

The tiger population will dwindle drastically within the next five years, if the plant is not removed from the forest, warn the researchers.

According to a recent study the total area of the Reserve is estimated to be 320 sq km of which the lantana had spread in 280 sq km area, posing a major threat to the very survival of tiger, the apex species in the food chain. The warning comes at a time, when the maximum tiger population is recorded in the MTR, which is estimated to range between 80 and 100.

While the population of tigers at Anamalai Tiger Reserve is estimated to be around 25, at the Kalakkad and Mundanthurai it is said to be around 15.

Talking about the dangerous effects of the invasive plant on the native plant species, researchers say that it spreads all over the area and creates a mat like structure, which will not allow the native plant species to regenerate. Lantana smothers the native species of grasses, plants and shrubs. The allelopathic substance in the plant will not allow other species to thrive.

The moisture in the ground will be sucked by lantana, making the place dry, wherever it grows. This is a very dangerous system, which will turn the plant into an inflammable material. During dry season a small fire in a dry patch of lantana in a forest land will result in a forest fire, destroying vegetation, birds and animals, the researchers said.

Spreading of lantana will destroy and degrade the biodiversity. In this process, herbivores such as Indian Gaur, Spotted deer and Sambar will not get the required grass, shrubs or other plants, which they feed on.

If the herbivores are affected, the predators such as tiger and leopard which feed on these animals will die of starvation. Already the straying of elephants and the consequent human — animal conflict is mainly due to lack of feed and water for the pachyderms. Added to that is the decline in tiger population and hence the warning, the researchers pointed out.

Solutions have been suggested by researcher on clearing the invasive species, which include assessing the threat by the species, prioritising the action for removing the invasive plant manually, restoring the areas with native species, which has to be a continuous process. If removal and restoring native vegetation is done for five years or more, it will help in regeneration of native species, they say.

Forest Department sources said annually from about 200ha lantana is cleared in MTR. However, the invasive species has become a mid canopy so the department is also taking measures for regeneration of native species of grass and shrubs.

To clear the invasive species, the local tribal people are utilised. The clearing is done as per the guidelines of National Tiger Conservation Authority, the officials added.

This article has been corrected for editing errors.

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