In a little under a decade, one of the strongholds for four species of native Strobilanthes plants in the upper Nilgiris has lost more than 90 % of its iconic plant population.
According to the researchers, they had recorded four species of Strobilanthes – S.homotropa , S.perrotettiana , S.wightiana and S.kunthiana in 2011 in large numbers. “We documented all four species in one particular region of the upper Nilgiris,” said Pradeep A.K., a naturalist and researcher, who along with Bince Mani, from the department of botany in the St. Thomas College, Palai, in Kottayam, Kerala, has been researching the plant species in the Nilgiris.
After almost 10 years, the researchers returned to the same location to ascertain the health of the ecosystem and to check on the Strobilanthes plants that they were researching. “The results have truly shocked us,” said Mr. Pradeep. While three species of Strobilanthes were displaced from around more than 90 % of the area in which they were recorded in 2010, one species – Strobilanthes perrotettiana had become locally extinct.
“While this is only a survey done in a small area of the Nilgiris, the displacement of the four Strobilanthes species points to fears of similar declines across the district,” said Mr. Pradeep.
Mr. Mani, said this decline could be representative of the decline in native biodiversity across the Nilgiris. “As we are studying Strobilanthes species, we are seeing such declines in these plants. But other native plants and wildlife too are possibly being displaced by invasive species, habitat loss, climate change and other anthropogenic factors,” he said.
The researchers said that habitat restoration was the only means to stop the decline in native species. “Each species of Strobilanthes grows in specific areas and specific micro-climates. For instance, S. zenkeriana , another species, grows along rocky outcrops, while S.homotropa grows inside patches of Shola forests,” said Mr. Pradeep.
The researchers said that after being seen gregariously flowering in 2011, Strobilanthes homotropa , which should flower again in 2021, is only seen in a fraction of the total area it was seen a decade ago. “There are only four to five plants left of S.homotropa and they will flower next year. My suggestion would be to remove the exotic and invasive flora in the area and help facilitate the species to re-establish itself. Such strategies need to be replicated across the Nilgiris, especially in hotspots for native biodiversity, to help native flora re-establish itself,” he added.
