Foresting natural grasslands: Ecological threat

If you were to ask if we should grow more forests, a typical reply would be, “Of course, forests help fight global warming” or that “forests harbour life.” However, did you know that “growing” artificial forests, which replace the existing landscape, is not always the best of choices? Yes, although it seems counter-intuitive, artificial forests may sometimes do more harm than good.

A recent study by researchers at the National Centre for Biological Sciences (NCBS), Bengaluru, University of Leeds, UK, and Manipal Academy of Higher Education, Manipal, has traced some of these misinformed decisions, made in the past, trying to grow forests in the shola-grassland landscapes in the Nilgiris. The study is published in the journal Biological Conservation.

Grasslands are naturally occurring landscapes dominated by grasses rather than shrubs or trees. They are complete and unique ecosystems and support diverse plants and animals, some of which are endemic. The shola-grassland mosaics, comprising of the stunted tropical forests called Sholas, amidst rolling grasslands, are found in the higher elevations of the Nilgiris in South India. They are believed to have existed for over 20,000 years. In the recent century, human interventions in these landscapes have resulted in some severe ecological damage.

“As ecologists, we constantly encounter ecosystems which have some history of human interventions. In India, where humans have lived for thousands of years, it is critical to know this history to inform how we interpret what we see today,” says Dr Jayashree Ratnam, study author and associate director for Wildlife Biology and Conservation programme at NCBS.

The research traces the history of these grasslands using historical records and literature since the colonial period. It finds that colonial forest officials introduced more than 40 alien species like acacia, pine, silver oak, and eucalyptus to the Nilgiri plateau and widely planted them from the 1820s to 1937. These efforts gained momentum when an additional 600 acres of grassland came under plantation in 1856. By the year 1950, 4,500 acres in the Nilgiris were under plantation. Critically, even though native tree species planted in the grasslands repeatedly failed to establish, this did not raise questions as to whether trees belonged in the grasslands.

“We presume that the British loved this landscape as it reminisced their homeland, and wanted to settle in the Nilgiris. Once settled, they misperceived the grasslands as degraded ecosystems due to persistent fires and cattle grazing by local tribes. It led to the idea that these grasslands needed to be converted to tree-clad forests. Further, the need for timber and firewood for the settlements led them to invest in the planting of economically important plant species over native ones,” explains Atul Joshi, from NCBS who worked on the archives of the India Office in London to detail this history for the study.

In the name of ‘scientific forestry’

The study also notes how the colonial foresters tried to regulate the natural landscape in the name of scientific forestry and conservation and that many of these efforts were driven by the requirement for more timber. In the shola grasslands, where there was no timber, not realising the 20,000 years history of these grasslands, the foresters attempted to afforest the landscape.

It’s not only the colonial foresters who are to be blamed; independent India was not too wise either! The relentless plantations continued, and by the end of the 20th century, about 32,500 acres of shola grasslands were under plantation. This further degraded the landscape and today, these grasslands act as a prelude to the fate of remaining grasslands, if misinformed human interventions continue in such ecosystems.

“The misperception that all grasslands are degraded ecosystems needs to change,” asserts Dr Ratnam. “Natural grassy biomes harbour unique biodiversity and provide distinct ecosystem services. They should be considered as important as natural forest ecosystems. The shola grasslands are heavily threatened due to historical land-use changes and severe invasions by alien plant species. Remnant grasslands need to be protected from further conversions and invasions,” she appeals.

The case of shola grasslands is not a peculiar one, but one of many examples of how unscientific assumptions have threatened the existence of entire ecosystems. Even after two centuries, most policymakers and forest managers continue to treat grasslands as degraded ecosystems and introduce alien invasive species. Perhaps the time is now ripe to let go of our long-held, widespread, and outdated misconceptions before more damage is done!