Community‐Managed Systems as Nature‐Based Solutions: Effects of Elevation and Size on Floral Richness and Carbon Stock of Sacred Groves in Kerala, India

ABSTRACT

Limiting global warming to 1.5°C–2°C requires rapid reductions in atmospheric carbon, highlighting the need to conserve ecosystems with high carbon stock potential. Sacred groves are culturally protected forest fragments maintained through traditional practices and represent community‐managed landscapes with significant potential as nature‐based solutions. This study evaluated the influence of elevation and grove size on plant species richness, carbon stock and soil properties in 55 sacred groves (31 lowland, 19 midland and 5 highland; ranging from 0.025 to 20.2 ha and from 3 to 906 m above mean sea level) across different physiographic regions of Kerala, India. Aboveground biomass carbon was estimated using allometric equations, and soil organic carbon was quantified by wet digestion; these components were combined to estimate total carbon stock. Species richness, carbon stock and soil properties were analysed across elevation and grove‐size categories using one‐way ANOVA, Kruskal–Wallis tests and multiple linear regression. Total carbon stock ranged from 30.46 to 318 Mg ha ⁻¹ (mean 113 Mg ha ⁻¹ ) but showed no significant relationship with elevation or grove size. In contrast, plant species richness (5–177 species) varied significantly across both factors (elevation: p  = 0.005, grove size: p  < 0.001). Sacred groves in the midland region supported the highest mean species richness (70 species) among elevation classes, compared with 56 in highland and 37 in lowland groves, while larger groves harboured more species (71) than medium (67) and small (30) groves. Multiple regression identified soil nitrogen as the strongest predictor of species richness (adjusted R ²  = 0.19), with grove area showing a consistent positive but marginal effect, whereas total carbon stock was best explained by exchangeable potassium (adjusted R ²  = 0.13). Soil properties, particularly exchangeable potassium (highest in midland groves, 0.004%) and bulk density (highest in highland groves, 1.76 g cm ⁻³ ), exhibited distinct physiographic patterns. The results demonstrate that sacred groves consistently store substantial carbon irrespective of size or elevation, whereas biodiversity conservation is strongly influenced by grove extent and elevation. These findings underscore the role of sacred groves as effective nature‐based solutions, where traditional stewardship supports both biodiversity conservation and climate change mitigation in human‐dominated landscapes. Integrating systematic management and ecological restoration practices into existing conservation frameworks, with active community participation, is recommended.