The lack of rains in The Nilgiris this year has brought into focus the impacts of erratic weather to the district’s water security.
However, a less visible and more alarming facet of the warming climate in the Western Ghats is its impacts on native forests in the Nilgiri Biosphere Reserve (NBR), with researchers warning of “erratic, unpredictable seasons” leading to widespread mayhem within forest ecosystems.
He said while temperature was an important factor, that it was not the only driver dictating the start, end and duration of seasons within the Nilgiri Biosphere Reserve’s forests.
Western Ghats: Response to Climate Change,’ published in 2024 in ‘Remote Sensing’, an open access peer-reviewed scientific journal, researchers used satellite imagery to examine forests in the Nilgiri Biosphere Reserve over two decades between the years 2000 and 2020, and how they were responding to changing temperature and rainfall, according to a study titled ‘Mapping forest phenological shift in Nilgiri Biosphere Reserve.
These changes were having an impact on the four forest types analysed by the researchers. They mapped the ‘Start of season’, when vegetation in the Nilgiri Biosphere Reserve becomes green, ‘End of Season’, when the active greening of the forests ends and Length of Season, the period between the start and end of the greening season, to try and understand the effects that climate was having on local ecology. The end of the growing season also changed differently in different forest types. He also stated he noticed Magnolia nilagirica , an endemic species native to the Western Ghats, that usually begins flowering at the end of the monsoon, began to do so as early as the end of June. “The flowering of several endangered endemic grassland plants has also reduced drastically. The scapigerous impatiens endemic to these grasslands, Impatiens clavicornu (Club-spur balsam) among them, have flowered far less than in past years. These are already a narrow range, threatened species. So a weak flowering season is not inconsequential. It means fewer seeds set, a thinner seed bank carried into the next year, and less of a buffer if conditions turn unfavourable again. Conditions like this can genuinely push already endangered species further into risk [of extinction],” he added.
Apart from recording an annual increase in temperature across the Nilgiri Biosphere Reserve by 0.01 degrees Celsius every year between 1950 and 2018, they also found the average amount of rainfall decreased by 3.97 millimeters every year during the same period.
This means that climate change is not simply making forests ‘greener’ or ‘less green’; it is changing the timing of their biological activity,” he said, adding that the broader message is that climate change can alter when vegetation grows. “Monitoring these changes can help forest managers identify vulnerable ecosystems and plan conservation and restoration strategies earlier,” he added.
“In some periods, vegetation started its growing season later; in another period, it started earlier.
