Kerala’s Sacred Groves Preserve Vital Ecological Functions Despite Their Small Size

Kerala’s centuries-old sacred groves are doing far more than preserving patches of native vegetation. A new study by researchers from the Central University of Kerala has found that these culturally protected forest fragments continue to sustain important predator-prey interactions even when surrounded by farms, settlements and home gardens.

The research, published in the Journal of Applied Ecology, examined sacred groves in Kerala’s Kasaragod district and compared them with nearby multi-storied home gardens. Researchers wanted to understand whether these relatively small and isolated forest patches continue to function ecologically, rather than simply harbouring individual species.

The team selected 12 locations situated between about 8 and 44 kilometres from the Western Ghats. Each sacred grove was paired with a nearby home garden located roughly one to two kilometres away. Fieldwork was conducted during January and February of 2024 and 2025, when insectivorous birds are particularly active in the region.

To measure predation, scientists placed artificial caterpillars and other sentinel prey at the study sites and later examined them for bite and attack marks. The results showed that overall caterpillar predation was consistently higher inside sacred groves than in neighbouring home gardens.

Arthropods, particularly ants, accounted for the largest proportion of attacks, while birds formed the second major predator group. Predation by both arthropods and birds was greater inside sacred groves, indicating that these patches retain active ecological food-web interactions despite their relatively limited area.

Researchers also examined how isolation from the Western Ghats affected these interactions. Predation within sacred groves declined as distance from the Western Ghats increased, suggesting that connection with the larger biodiversity hotspot still influences ecological functioning. Home gardens showed a different pattern, with some forms of predation increasing farther from the Ghats.

One of the most significant findings was that the physical size of a sacred grove did not explain the strength of predator activity. Instead, habitat complexity appeared to be more important. Even small forest fragments maintained comparatively strong predator-prey interactions, suggesting that structurally rich vegetation can partly offset the ecological effects of fragmentation.

This gives sacred groves an importance that extends beyond their cultural and religious value. Predators such as birds, ants and other arthropods help regulate herbivorous insect populations, contributing to ecosystem stability and potentially providing natural pest-control services in surrounding landscapes.

Sacred groves have traditionally survived because communities protected them for religious and cultural reasons. Kerala’s Forest and Wildlife Department also recognises their ecological importance, noting that these patches can harbour diverse plants, birds, butterflies and water resources while functioning as small refuges within heavily modified landscapes.

The Central University of Kerala study therefore strengthens the case for conserving even very small sacred groves. Rather than judging forest fragments solely by their area or number of species, conservation planning may also need to consider whether they continue to support interactions such as predation, pollination and seed dispersal.

The findings demonstrate that Kerala’s sacred groves remain functioning pieces of the wider Western Ghats ecosystem. Protecting them could help maintain biodiversity, ecological connectivity and natural ecosystem services across increasingly human-dominated landscapes.