Plant Diversity Indices and Community Composition in Sacred Groves of Imo State: Implications for In-Situ Conservation

Sacred groves are culturally protected remnant forest patches that function as informal in-situ conservation areas, and their botanical documentation in Imo State, South East Nigeria, provides important insights for integrating traditional conservation knowledge into formal biodiversity management. This study assessed plant species diversity, community composition, and conservation value of eight sacred groves across four Local Government Areas in Imo State: Owerri West, Ahiazu Mbaise, Ihitte Uboma, and Obowo. Vegetation surveys were conducted using 20m x 20m plots (three per grove) during the wet season. All vascular plant species were recorded and identified. Shannon-Wiener diversity, species richness, and importance value index were calculated. Community composition was compared between grove types (deity groves, burial groves, and community assembly groves) using multivariate analysis. A total of 198 vascular plant species were recorded across all eight groves, considerably exceeding species richness in adjacent farmed areas sampled as reference sites. Mean species richness per grove was 72 species, compared to 23 in farmed reference plots. Deity groves had significantly higher diversity (H' = 3.82) than burial groves (H' = 3.14) and community assembly groves (H' = 2.97), attributed to stricter access taboos limiting human disturbance. Twenty-three species of conservation concern, including threatened forest trees and herbs, were documented exclusively in sacred groves. Diameter class distributions confirmed active regeneration in all groves. The study concludes that Imo State sacred groves are ecologically significant informal conservation areas and recommends their formal recognition in state land use legislation as community-managed biodiversity reserves.

Keywords: sacred groves, plant diversity, in-situ conservation, community composition, Imo State