Environmentalists fear that lantana camara, considered a worst weed worldwide because of its invasiveness, could cause disturbance to bio-diversity of forest area in Erode district.
The weed forming dense, impenetrable thickets are gradually taking the place of native bushes and pastures, according to cattle grazers on the hills. Scientists say the purple-black berry-like fruit is consumed by birds and the droppings enable the weed’s spread far and wide.
Butterflies, bees and other insects are also attracted to the nectar in the flowers. But, the weed threatens agriculture and pastoral production, forestry and biodiversity of conservation areas, says E.N. Sivasenapathy, president of Bargur Cattle Rearers’ Association. Scientists explain that lantana that forms strong roots releases chemicals into the soil thereby preventing germination of other plant species.
It grows strongly in altitudes of around 1,000 m above sea level, the range in which the forest area in Erode district is spread out.
While it invades open sunny areas such as roadsides, cultivated pastures and fence lines, and becomes all pervasive on the forest edges, it is not shade-tolerant, and hence, there is no threat to the forest cover as such.
But, the weed has the potential to reduce food availability for grass-eating deer and Indian Gaurs that form the prey base to the tigers in the Sathyamangalam forests.
The Forest Department has been clearing lantana camara as a component under the Tamil Nadu Bio-Diversity Conservation and Greening Project for the last three years.
The weed has been spreading fast and is being destroyed through burning in places of dense formations in a phased manner, says District Forest Officer, Erode Division, Nagarjan.
But, since the weed is resilient to burning, the Forest Department is also worried about its continuing spread that is causing food shortage for herbivores due to shrinkage of natural vegetation. The weed has gained dominant presence right from the foot of the hills.
According to the scientists, the weed is controlled worldwide with an integrated approach that combines fire, mechanical, chemical and biological methods, and re-vegetation.
