The song of grass and water | WWF India

After almost three months of lockdown, I was glad to get out and be in the field again. And the exciting part was that we were going to be in the Mukurthi National Park, one of the last remaining areas of the original Shola- grassland complexes in the Nilgiris.

More than 90% of the original habitat of the Nilgiris has been modified with exotic and invasive species such as Wattle, Eucalyptus, and the Tea gardens that have become synonymous with the region. Mukurthi is not only a true wilderness here but also the origin of 2 major rivers of Tamil Nadu -- Bhavani and Moyar and the home to the endemic Nilgiri Tahr.

A breathtaking landscape, Mukurthi National Park is a relatively small (78 sq. km) protected area in Tamil Nadu comprising tall peaks and grasslands.

Kollaribetta (2,629 m), Mukurthi (2,554 m), and Nilgiri (2,476 m) are the three main peaks of the park and we covered the first one as part of our three-day survey. The rest of the plateau, which is about 2000 m in height, is a vast expanse of rolling grasslands interspersed with patches of Shola forests in the valleys and the mountain folds.

Shola forest and grassland mosaic

Being a high elevation plateau, in the middle of an otherwise tropical region, makes this place unique. And as you can imagine, this area has very high endemism of plants, mammals, birds and amphibians.

Another important character of this shola-grassland complex is its water retention capacity. On the one hand, it reduces the run-offs during heavy rains, thus protecting downstream areas from flooding and on the other, maintains the soil moisture and stream flows during the lean season. Even the smallest of the Shola forest patch would have a trickle coming down from it during the peak summer. These forest streams eventually join together to form the perennial rivers such as Bhavani that supports much of the economic activities in the region, including almost 50% of Tamil Nadu’s hydropower generation and water supply to industrial cities like Coimbatore and Tiruppur that contribute to about 16% of Tamil Nadu’s state GDP.

As with every natural place these days, all is not well with this paradise. Much of this native ecosystem in Nilgiris has been converted to plantations. Even in Mukurthi, where the ecosystem is still functional, invasives like Wattle, Scotch Broom, and Gorse are taking over patches of forest. The Forest department has been removing some of these invasive species regularly, but they keep regenerating.

Patches of old wattle (dark green) and young wattle (light green) invading the grassland

A recently concluded 3-year-long study in the area by ATREE, one of our partners in the Noyyal-Bhavani river conservation program, indicates that invasive plants like Wattle exert a greater water demand to the region’s hydrology than the native grassland that they are invading. The study found that the invaded land cover showed an increase of 10% in the Evapotranspiration (water loss) to that of pure grassland. Along with changing climates, these impacts can be expected to further increase their prominence, driving the water balance in the landscape to a state of increased vulnerability. This would have implications far beyond this region as this landscape serves as a water tower for both Tamil Nadu and Kerala.

WWF India in partnership with ATREE and Tamil Nadu forest department is currently working on a research project to develop strategies for restoration of these grasslands and to bring back environmental flows to the Bhavani river and its key tributaries.

Enhanced scientific knowledge about methods of restoration, along with sustained invasive management efforts, can help restore this vital forest-grassland-water ecosystem. This would need more resources and collective action by multiple actors. With increased awareness about its ecological and economic importance, I’m hopeful that together we would secure this pristine landscape.

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