Climate change and sustained human pressure are reshaping forest landscapes across India, and new research from the northern Western Ghats suggests that these forces may be tipping the balance in favour of deciduous forests over evergreen ones, especially at lower elevations.
A recent study examining forest composition in the northern Western Ghats finds that areas experiencing high human disturbance and water stress show a marked decline in overall tree diversity, with evergreen species being the most affected. At the same time, deciduous tree species appear to thrive under these altered conditions, increasing in number where disturbance is frequent and prolonged.
The research was carried out as part of an on-ground restoration programme in Maharashtra, where scientists first conducted biodiversity surveys of birds, amphibians and reptiles to identify priority areas for conservation. According to study co-author Rohit Naniwadekar, the focus was on forests that were poorly protected yet still rich in biodiversity. These surveys revealed that low-elevation forests, despite receiving less attention than higher-altitude ecosystems, support an unusually high diversity of birds and reptiles.
However, these low-elevation forests are also among the most threatened. Much of the land lies outside government ownership and is privately or community held, making it vulnerable to conversion into plantations of cashew, rubber and mango. In many places, remaining forest patches are repeatedly harvested for fuelwood. Trees are cut, allowed to regenerate for a decade, and then harvested again, creating a cycle of chronic disturbance that profoundly alters forest structure.
Faced with the challenge of restoring such degraded landscapes, researchers encountered a critical dilemma: what kind of forest should be restored when no undisturbed reference forests remain? To answer this, the team conducted a detailed ecological assessment across 120 tree plots spread over a 15,000-square-kilometre area in the northern Western Ghats. The plots represented a range of elevations and disturbance histories, from heavily disturbed forests to relatively intact sacred groves.
The analysis revealed two striking patterns. First, repeated human disturbance was found to drive a shift from evergreen-dominated forests to deciduous-dominated ones. Evergreen species, which regenerate slowly, are selectively lost when forests are cut again and again, while deciduous species recover more easily. Second, the study found that evergreen trees persist even in the driest parts of the landscape, sometimes making up nearly half of the tree community, indicating that climate alone does not fully explain their decline.
By examining climate water deficit, a measure of the balance between rainfall and water loss, researchers showed that wetter sites were largely evergreen, while drier sites still retained a significant evergreen presence. This pointed to the combined role of climate stress and human disturbance in shaping forest composition.
These insights have directly influenced restoration strategies. Since deciduous species often regenerate naturally once disturbance is reduced, researchers argue that active restoration should prioritise evergreen species that have been selectively removed. This approach is particularly significant for conservation, as the Western Ghats are home to around 650 evergreen tree species, nearly two-thirds of which are endemic to the region.
The findings also highlight the broader ecological consequences of chronic human activity, such as fuelwood extraction and land conversion, which can rapidly push forests into a more deciduous state. However, some experts caution against oversimplifying the causes behind this shift. Palynologist and palaeoecologist Anupama Krishnamurthy notes that the study largely frames human pressure in terms of biomass extraction, while overlooking other major drivers such as tourism infrastructure, roads, real estate development and plantation expansion.
Ecologist Nina Sengupta echoes this concern, pointing out that forests in India have long coexisted with human communities. What has changed, she argues, is the scale and intensity of disturbance. Focusing narrowly on extraction risks missing how modern development pressures are transforming forest ecosystems in new ways.
Krishnamurthy also warns against broadly interpreting increased deciduousness as a sign of degradation across the Western Ghats. The length of the dry season varies significantly from south to north, naturally favouring deciduous species in northern regions where dry periods can last four to five months. Topography, slope and aspect further influence species composition, even within the same elevation and rainfall zones, making generalisations difficult.
Responding to these concerns, Naniwadekar acknowledges that each forest site has its own ecological story. Despite Maharashtra’s forests being generally more deciduous than those in the southern Western Ghats, the study unexpectedly found a high proportion of evergreen trees across the sampled landscape. He adds that ongoing data collection will help clarify how factors such as seasonality and topography interact with disturbance over time.
The study also raises a larger, unresolved question: can climate change alone convert evergreen forests into deciduous ones? While some climate models predict reduced rainfall in parts of the Western Ghats and more erratic monsoons, uncertainty remains high. Researchers caution that it is too early to draw firm conclusions about future forest transitions.
What is clear, however, is that the combined effects of climate stress and human pressure are already reshaping forest ecosystems in the Western Ghats. As restoration efforts expand, scientists emphasise the need for locally grounded strategies that recognise ecological complexity, protect endemic evergreen species, and address the full range of human impacts shaping these fragile landscapes.