Effects of Sand Mining on Species Diversity, Stand Structure and Carbon Stocks in a Tropical Forest in Ghana: Implications for Biodiversity Conservation and Ecosystem Services

Abstract

The extractive industry, particularly sand mining, underpins infrastructure and socioeconomic development in many tropical countries but poses severe ecological risks when poorly regulated. This study quantified the long‐term effects of sand extraction on plant diversity and conservation status, stand structure and carbon stocks at a 30‐year abandoned sand mine site within a tropical forest in Ghana. The site was stratified by extraction intensity into sand mine core (SMC), sand mine buffer (SMB) and non sand mine (NSM) areas. Nested plots (400 m 2 ) were randomly established across the sites to collect data on plant species and tree biomass. The results showed that species richness declined significantly from 81 species in the NSM to 45 in the SMC. Stand‐structural attributes (height, basal area and density) collapsed to zero with a corresponding carbon stock of 00 ± 00 (tC/ha) in the SMC compared with 69.89 ± 16.06 (tC/ha) in the NSM. Multivariate analysis revealed the near‐total reassembly of plant community in mined areas. Nonmetric multidimensional scaling (nMDS) of species importance value index (IVI) clearly separated the NSM from mined sites, with Bray–Curtis dissimilarity highest between NSM and SMC (94.07%), but relatively similar between SMB and SMC (50.99%). SIMPER analysis identified the replacement of sensitive native species at the NSM (e.g., Mallotus oppositifolius, IVI: 54.09) by resilient grasses at the SMC (e.g., Imperata cylindrica, IVI: 58.26). Conservation status assessments using both localised star rating and IUCN categorisation confirmed significant losses of high‐priority conservation species in mined areas. This study demonstrates that unregulated sand mining drives irreversible biodiversity loss and profound shifts in the community structure and severely impairs carbon sequestration. We argue that integrating sustainable sand mining practices and restoration targets into national land‐use policies is critical to safeguard tropical forests’ biodiversity and their ecosystem services.