Sacred groves, locally known as Devara Kadu in Karnataka, represent one of the oldest forms of community-based forest conservation, safeguarded through traditional beliefs, cultural values, and customary practices. These ecologically significant forest patches serve as natural regulators of environmental processes while providing a wide range of ecosystem services essential for ecological sustainability and human well-being. This review synthesizes existing literature on the ecological functions and ecosystem services of Karnataka’s sacred groves, drawing on studies of biodiversity, soil science, hydrology, biogeochemistry, microbiology, and traditional ecological knowledge. Sacred groves exhibit multi-layered vegetation, continuous litter inputs, substantial soil organic carbon stocks, and relatively undisturbed soil conditions that collectively support biogeochemical cycling, biological regulation, and physico-chemical environmental modulation. The review highlights their role in biodiversity conservation, climate regulation, hydrological balance, soil conservation, nutrient cycling, carbon sequestration, and habitat connectivity, and examines their contribution to the conservation of endemic, rare, threatened, and medicinal plant species, as well as pollinators, wildlife, and microbial diversity. Sacred groves function as dynamic social-ecological systems that regulate key ecosystem processes through the interaction of vegetation, soils, microorganisms, hydrology, and long-term cultural stewardship. Significant knowledge gaps remain, particularly regarding direct process-based measurements of carbon sequestration rates, groundwater recharge, pollination effectiveness, and microbial community function. Future research should prioritize interdisciplinary, process-based studies to quantify ecosystem functions and strengthen the integration of sacred groves into conservation policies, restoration programmes, and climate adaptation strategies.
