Overview
A recent study published in the open‑access journal Remote Sensing examined how forests in the Nilgiri Biosphere Reserve responded to temperature rise and rainfall decline between 2000‑2020. The findings reveal shifting phenology – the timing of biological events – that could destabilise the entire Western Ghats ecosystem.
Key Developments
- Average temperature rose by 0.01 °C per year (1950‑2018) while rainfall fell by 3.97 mm per year.
- During 2001‑2010 (Phase I) the Start of Season (SOS) was delayed in all four forest types, shortening the growing period for dry, semi‑evergreen and wet evergreen forests.
- In 2011‑2020 (Phase II) SOS advanced across all forest types, lengthening the greening season.
- Moist deciduous forests uniquely lengthened by 4.37 days per year in Phase I.
- Field observations report drying of Shola forests, loss of epiphytes, and early flowering of the endemic Magnolia nilagirica.
Important Facts
The study mapped four forest categories: moist deciduous, dry deciduous, semi‑evergreen, and wet evergreen. Phase I showed delayed SOS, while Phase II showed an advance, indicating increasing variability rather than a linear trend. Researchers stress that temperature interacts with rainfall, soil moisture, photoperiod, and drought, making phenological responses complex.
Local ecologist Godwin Vasanth Bosco highlighted that invasive species such as Prosopis juliflora and Lantana camara have further degraded dry scrub zones, preventing grass regrowth during the monsoon.
Exam Relevance
Understanding phenological shifts is vital for GS‑III (Environment &