Linking woody plant species richness with selected ecosystem services and dendrometric features in Okalma natural forest reserve

Abstract

While the human population is increasing globally, the sustainability of ecosystem services is declining. Okalma Natural Forest Reserve in Sudan hosts high woody plant species richness that support ecosystem services, soil health, and local livelihood. This study aims to assess the relationship between woody plant species richness, carbon stock, dendrometric features, soil chemical properties, recreation services, and income sources. Data were collected from 178 circular sample plots with a radius of 17.84 m (area of 1000 m3 each) along 17 transect lines, complemented by 510 questionnaires and soil analysis. We recorded 30 woody species (tree and shrubs), with species richness positively correlated with carbon stock (R2 = 0.88), tree height (R2 = 0.82) and recreation preferences (R2 = 0.90), but negatively correlated with soil sodium and nitrogen (R2 = - 0.91). Importance value index (IVI), basal area, and seedling density varied significantly (P < 0.05) among sites. Outdoor recreation activities such as enjoying fresh air and forest fruit were preferred over hunting and games. However, the high dependence on non-timber forest products highlights the need for sustainable use and industrialization of these resources. We recommend conserving species with low density, enhancing recreation facilities, and maintaining soil health for sustainable management of the reserve.