Invasive weed, 17 plants stifling Kaziranga

A Vitamin D3-rich weed and a shrub with roots that wild boars love to gorge on are among the 18 invasive plants stifling the Kaziranga National Park and Tiger Reserve, the best-known address of the greater one-horned rhinoceros on the Earth.

Damage to Kaziranga

• Kaziranga has had to deal with encroachment, poaching, and annual floods for decades. But none of these has been as damaging to the health of the 1,300-sq. km tiger reserve as the green invaders that have gone under the radar until now.
• Kaziranga’s Field Director documented 18 of invasive species silently taking over the landscape at the cost of indigenous grasses, shrubs and trees the herbivores of the park sustain on.
• The list submitted to the Wildlife Institute of India (WII) did not contain the “usual culprits” of many protected areas in India – parthenium and lantana that threaten more than 40% of India’s tiger reserves.
• It did mention ipomoea (Ipomoea carnea) and mimosa (Mimosa himalaica) but marked them as largely controlled and not much of a worry now.

Parthenium and Lantana

• Parthenium (Parthenium hysterophorus) is believed to have come to India as contaminants in a consignment of wheat imported from the U.S. in the 1950s while lantana (Lantana camara) was brought by the British as ornamental plants from South America two centuries ago.
• This is the first time that such species have been identified with threat estimation. Many like the Bombax ceiba and Largestroemia speciosa, trees locally called ‘semul’ and ‘ejhar’, need immediate attention to save the grasslands vital for the survival of the rhino and other herbivores.

Invasive plants are fast clogging paths and grasslands.

• The herbivores usually avoid the invasive plants which regenerate at an alarming speed and threaten to edge out the indigenous flora.
• Some of the invasive plants have a toxic impact on the landscape after remaining underwater, which is often for two months every monsoon.

Outweighing utility

• Some weeds have herbal properties, but their toxicity outweighs their utility.
• Cestrum diurnum or day-blooming jasmine of West Indies origin “coming up gregariously” on the Brahmaputra sandbars.
• The plant is otherwise a source of Vitamin D3.

Prelims Takeaway

• Indeginous and Invasive species
• Kaziranga national park