Worship sites and roads drive night‑time light spill into Kerala’s protected forests

Artificial light at night is spilling into Kerala’s Western Ghats protected areas, altering habitats and animal behaviour, a new study finds. Researchers used 2024 satellite night‑light data and OpenStreetMap infrastructure layers to assess 21 reserves and the surrounding landscape. They measured light exposure inside each reserve and in five concentric rings extending up to 30 km from the boundaries. Light intensity varied widely; Periyar Tiger Reserve West recorded the highest average and peak values. Within the reserves, the number of temples and other worship places showed the strongest link to higher illumination, according to lead author Haripriya S. In the outer zones, road density and the concentration of activity hubs such as tourist spots were the main drivers of brightness. The analysis also revealed that zones beyond 5 km from a reserve’s edge received more light, with the 10‑20 km band contributing the most, followed closely by the 20‑30 km band. This pattern indicates that light pollution reaching protected areas does not come solely from nearby sources but also from a broader landscape. The authors note that artificial night lighting, a relatively under‑studied threat, can disrupt animal movement, navigation, reproduction and predator‑prey interactions, and they plan further research into these effects.

Context

Night‑time lighting can interfere with wildlife that rely on darkness for foraging or mating. In forest reserves, even scattered glow from distant roads or illuminated temples can change how animals use the habitat, highlighting the need for broader lighting management beyond reserve borders.