Climate change combined with sustained human pressure is reshaping forest ecosystems in the northern Western Ghats, with new research showing a clear shift away from evergreen trees towards deciduous species in many low-elevation forests.
The study, conducted across parts of Maharashtra, finds that forests facing repeated human disturbance and water stress have lower overall tree diversity, particularly of evergreen species. In contrast, deciduous trees become more dominant in areas where forests are frequently cut or exposed to prolonged dry conditions.
Researchers carried out the study as part of a long-term restoration programme aimed at identifying highly threatened yet biodiverse forest patches. Baseline surveys of birds, amphibians and reptiles revealed that low-elevation forests in the northern Western Ghats support unusually high biodiversity, often surpassing that of higher-altitude forests. However, these areas remain poorly protected, with much of the land privately or community owned.
According to the researchers, rapid land-use change is a major driver of forest degradation. Large tracts of low-elevation forest are being converted into cashew, rubber and mango plantations. Remaining forest patches are often subjected to repeated fuelwood extraction, where trees are cut, allowed to regenerate for several years, and then harvested again. This cycle of disturbance, the study notes, gradually filters out slow-growing evergreen species.
To better understand these changes, the research team sampled 120 forest plots across a 15,000-square-kilometre landscape, covering sites with different disturbance histories, from heavily exploited areas to relatively undisturbed sacred groves. The findings showed that repeated cutting strongly favours deciduous trees, while evergreen species decline sharply. Surprisingly, evergreen trees were still found even in the driest parts of the landscape, indicating that climate alone does not explain their loss.
By analysing climate water deficit, a measure of rainfall versus water loss, the study found that wetter sites were dominated by evergreen trees, while drier sites still retained a substantial evergreen presence. This suggests that human disturbance, when combined with water stress, plays a decisive role in driving forests towards deciduous dominance.
These insights are shaping restoration strategies in the region. Researchers argue that while deciduous species often regenerate naturally once disturbance decreases, evergreen species struggle to recover on their own. Restoring evergreen trees is therefore critical, especially as the Western Ghats are home to around 650 evergreen tree species, most of them endemic.
Experts not involved in the study caution against overgeneralising the findings. They point out that longer dry seasons in the northern Western Ghats naturally favour deciduous species and that factors such as slope, aspect and infrastructure development also influence forest composition. Tourism projects, roads, real estate expansion and plantations now exert pressures that go beyond traditional biomass extraction.
The study also raises questions about the future impact of climate change on forest types. While some models suggest rainfall may become more erratic or decline in parts of the Western Ghats, researchers say uncertainty remains high. For now, the evidence indicates that climate stress and human activity together are accelerating changes in forest structure, with important implications for biodiversity conservation and restoration planning in one of India’s most ecologically significant regions.