Removing invasive flora is having very limited impact on restoring native forests and grasslands in the Nilgiris, a committee comprising forest department officials, ecologists and experts on invasive species removal has found during its recent visit to the district.
The committee, which is looking into the feasibility of the recommendations put forth by the High Court-appointed expert committee for invasive species management, recently visited Gudalur, Mudumalai Tiger Reserve, Korakundah, Upper Bhavani and Avalanche, is focusing on areas where invasive wattle trees were removed to ascertain whether this was helping Shola forests and grasslands to re-establish.
However, the officials and experts in the committee told The Hindu that they came across multiple complexities that had highlighted the challenges the forest department faced in removing entirely the exotic species from the Western Ghats landscape.
“For instance, in areas where invasive wattle trees have been removed, exotic species of grass, such as Vulpia myuros have come up, which is not palatable for local wildlife. Other grasses in wattle-cut areas such as Isachne kunthiana, which is native to the landscape, have also come up in these areas. However, this grass too is not palatable, and as there is not enough expertise to identify these grasses and remove them,” said an ecologist who was part of the committee.
The members of the committee said they were pushing for the establishment of nurseries that grew not just Shola tree species but also native grasses that could be planted to help restore degraded or destroyed grasslands.
Careful monitoring of areas where invasive species have been removed, as well as site-specific restoration programmes is the need of the hour to have any long-term impact to help landscapes recover, said another expert on invasive species management.
“The problem we are seeing with removing wattle is that they persistently attempt to re-establish in locations where they have been removed for a number of years. So a patch where invasive wattle has been removed needs to be maintained every year for a period of at least five to six years and this will require persistence and substantial funding,” said a top State forest department official.
The department has also noticed secondary invasion of Cytisus scoparius (Scotch broom) in Korakundah and Upper Bhavani, where wattle was removed, while another concern for the department is how to get rid of the exotic trees that have been removed.
“We are trying to assess the demand for wood, as the trees, once removed cannot just be left at the site,” said another official, who added that these challenges make the developing of a comprehensive strategy for restoring degraded habitats very complex.
Apart from wattle, the spread of Lantana camara and Senna spectabilis is another cause for concern. Forest officials believe Senna spectabilis has spread to more than 20 hectares in the Mudumalai Tiger Reserve.
