The Shola-grassland ecology of Mukurthi National Park (MNP), the conservation of its endemic flora and fauna, and the positive impacts of removal of invasive species from the landscape are being more thoroughly understood as a result of the Tamil Nadu State government’s flagship conservation programme - Project Nilgiri Tahr to help conserve the State animal.
Home to one of the largest populations of the Tahr in Tamil Nadu, the conservation of the keystone species is leading to better understanding of the ecology of relatively less-studied Mukurthi National Park, experts said.
According to C. Vidhya, Deputy Director of the Mukurthi National Park, one of the key takeaways from the project is understanding the diet of the Nilgiri Tahr population inhabiting Mukurthu. “The diversity of grasses in the habitats of the Tahr, and what it feeds on is being better understood,” she said, adding that the availability of endemic species of grasses, some of which are only found within the park, is a source of scientific interest.
“There is some overlap between what Tahr populations consume in other parts of their range within the State when compared with the population within MNP, but the population within MNP also consumes certain grasses that are found only within the reserve,” said Ms. Vidhya.
Learnings from these findings could prove crucial in safeguarding the future of the species, as the Forest Department is considering reintroducing the Tahr into areas where they have become locally extinct over the last two centuries.
“Understanding the diet of the Tahr will mean that any potential reintroduction plan will involve ensuring the grasses it depends on are also reintroduced to where the animals will be released. This is also helping the Forest Department in identifying and understanding the importance of native grasses,” said a conservationist from the Nilgiris, who has been following the project to conserve the species.
Ms. Vidhya said that the Forest Department also plans a survey of the complete floral composition of the area to understand the floral biodiversity contained within the park, and to potentially help in conserving flora that are at risk of extinction such as grasses like Eriochrysis rangacharii and trees like the Rhododendrom arboreum nilagiricum.
Invasive species removal programme
Since 2017, the State government has also begun removing invasive species that have spread within parts of the MNP, primarily wattle.
“In Mukurthi National Park, wattle is found growing a few kilometres from the Nilgiri Division boundary. It is seen growing into small trees due to strong winds. Every year, proposal are being submitted for the strategic removal of wattle from the park area. In the past three years, nearly 120 hectares of wattle have been removed under various schemes such as the Integrated Development of Wildlife Habitat, CAMPA and SADP,” Supriya Sahu, Additional Chief Secretary, Environment, Forests and Climate Change told The Hindu.
The removal of wattle will dovetail with the goals of Project Nilgiri Tahr, said Ms. Vidhya, by eventually leading to more usable habitat area for the species within the park itself.
Fortunately, the impact of climate change is yet to fully manifest within the park, translating to invasive grasses not being able to establish themselves.
“Project Nilgiri Tahr has already begun the study on the grass species available in the area. In the interim, we have found that the grasses at MNP are either palatable to the Nilgiri tahr or not, but there is no invasive grass. On removal of the wattle, the native grass species comes up naturally, requiring minimum intervention,” said Ms. Sahu.
M. Yuvarajkumar, Forest Range Officer (Mukurthi National Park Range), said that 57 hectares of wattle have already been removed, and that currently, 50 more acres of the invasive species are gin the process of being removed. He also said that from field observations, it was evident that the removal of invasive species was having a profound positive impact on local ecology and biodiversity.
“When an area is cleared of wattle, we see the growth of 2-3 species of native grasses, as well as Shola tree species. We also see that wildlife, particularly herbivores such as Sambar deer and Indian gaur almost immediately start utilising the cleared area, either to browse for food or to move between different patches of the habitat,” said Mr. Yuvarajkumar.
However, challenges to keeping the reserve free of invasive species remain, with cleared wattle patches regenerating due to existing seed banks. “This will require yearly maintenance work, with the new trees needing to be cleared for multiple years and being prevented from re-establishing,” he added.
Ms. Sahu also said that through wind dispersal, two invasive species from the Fabaceae family are spreading to areas bordering the reserve, which are being cleared by the Nilgiris forest division as they lie outside the territorial boundaries of Mukurthi National Park.
