CHENNAI: While the seasonal migration of elephant herds from Kerala to Valparai plateau usually kick-starts in August, it commenced early this year. Seven out of nine elephants from a group called ‘Monika’ were spotted by the Anamalai Tiger Reserve field staff on Monday. But, the biggest worry lurks in the form of the swamp lands part of traditional elephant corridors overrun by invasive alien species that are drastically depleting the natural fodder availability for elephants.
This could potentially lead to man-elephant conflict. The work done over the years by forest department and organisations like Nature Conservation Foundation (NCF) to mitigate conflict, and bring down human deaths to ‘zero’ in Valparai will be undone, if alien species is not removed. TR Shankar Raman, a senior scientist at NCF working on rainforests in the Anamalai mountains, said his team with the forest department’s help were able to identify 25 invasive alien species in Valparai.
The one species taking over most of the swamps is the Ludwigia peruviana. “Two decades ago, most swamps were with rich grasses, which most of the animals including elephants would relish. But, what we have been seeing in the last 3-4 years is expansion of Ludwigia in the swamp lands,” Raman said. There is no room for growth of native grasses, he added. No one knows how Ludwigia made its way into the hills.
Some available evidence shows tea plantations in the past grew this plant for biomass in the peripheral areas. Ganesh Raghunathan, who is leading a project on mitigating conflict in Valparai at NCF, said removal of invasive alien species, especially Ludwigia, from swamp lands that are closer to elephant corridors is crucial, and must be prioritised since these swamps determine their movement. ATR’s Deputy Director MG Ganesan said the forest department was chalking out a strategy for the removal.
“Most swamps fall under the private tea/coffee estates. As this is a recent phenomenon, we aren’t sure what is the most effective way of removal. The forest department requires help from tea companies and scientific organisations. In the absence of fodder here, there is a high possibility of escalation of manelephant conflicts.”
Additional Chief Secretary to Environment, Forests and Climate Change Department Supriya Sahu said, for the first time, the TN government came up with a draft policy, which identified and listed out priority alien species, including Ludwigia, that need to be removed to aid forest regeneration. “We are in the advanced stage of finalising modalities and operationalising the policy. Already, removal began in a few pockets on a pilot scale. ”
Supriya Sahu noted that 50 acres of Lantana have been already removed in Mudumalai where grass has started to regenerate. Next in line is identified site for removal of Senna Spectabilis on about 25 acres near Masinagudi.
PERUVIAN SPECIES COMPETE WITH NATURAL VEGETATION
Ludwigia peruviana, with common names Peruvian primrose-willow or Peruvian water primrose, is an aquatic and deciduous species of a flowering plant. It can grow to approximately 12 feet in height. While native to Peru, it was introduced in other nations for yellow flowers, and is now a common weed in swampy areas. The Peruvian primrose-willow forms dense colonies along the shore, and then creeps into the water where it impedes navigation, damages structures, and competes with native vegetation. This species is classified as a category I invasive species in Florida, where it clogs numerous lakes and rivers, and as a noxious weed by the Australian government.