Limiting global warming to 1.5-2°C requires an immediate reduction in atmospheric carbon, suggesting the urgent need to conserve ecosystems with high carbon potential. Tropical forest systems, especially those that have been conserved for several years, offer immense value in both carbon storage and biodiversity conservation. This study explores the role of sacred groves, the culturally protected forest fragments, as community-managed landscapes that contribute to climate change mitigation and conserve biodiversity. The influence of elevation and grove size on floral richness and carbon storage was examined across 55 sacred groves in Kerala, India. Biomass carbon was estimated using allometric equations, and soil organic carbon was quantified using the wet digestion method, which were then summed to determine the total carbon storage. Statistical analysis revealed that carbon storage was not significantly affected by either. However, both had a significant impact on species richness, with a notable interaction between them. The results indicated that the large groves in highland areas supported the greatest species richness, while small groves in the same physiographic zone had the lowest. Soil analysis showed higher exchangeable potassium in midland groves and elevated bulk density in soils of highland groves. These results highlight the intersection of biophysical characteristics and traditional stewardship in maintaining biodiversity and influencing ecosystem functioning. As biodiversity-rich systems are known to enhance resource use efficiency and biomass accumulation, conserving sacred groves presents a scalable, traditionally embedded solution. Recognising and strengthening such nature-based, community-driven conservation practices can play a pivotal role in achieving climate and sustainability goals.