In the dense forests of the Western Ghats and beyond, small pools of rainwater collected inside tree hollows are quietly sustaining entire ecosystems.
An international study published in Ecology Letters has revealed that these water-filled cavities often described as “islands in the sky” host complex aquatic micro-communities of insects and larvae. Though modest in size, they play a disproportionately large role in maintaining forest health.
Researchers found that these miniature habitats support intricate food webs that contribute to nutrient cycling and energy flow across forests. Their survival, however, depends on more than just rainfall or water quality. Forest connectivity is critical. When landscapes become fragmented, species struggle to disperse between trees, increasing the likelihood of local extinctions.
The study highlights that the Western Ghats exhibit particularly high functional diversity within these microhabitats, a feature scientists attribute to the region’s long-term climatic stability and deep evolutionary history.
The research team included Dr KS Anoop Das and KT Fahis from the Centre for Conservation Ecology at MES Mampad College in Kerala, working alongside collaborators from the Swiss Federal Institute for Forest, Snow and Landscape Research, ETH Zurich, SUPSI, and University of Campinas.
Supported by a Government of India DST-SERB (now ANRF) grant, the findings underscore a simple but powerful message: even the smallest natural features can have an outsized ecological impact. Protecting forests, therefore, means safeguarding not just the canopy and wildlife we see but also the hidden, rain-fed worlds thriving within tree trunks.