Edge-interior disparities in tree species diversity and soil physicochemical properties in a Nigerian strict nature reserve

Abstract

This study was designed to compare the variation in species richness, diversity of trees and soil physiochemical properties along the edge-interior gradient of a Nigerian Strict Nature Reserve located in Akure Forest Reserve, Ondo State. The forest was categorized into three habitats, namely: edge (0–100m), intermediate (100–200m), and interior (> 200m), depending on the distance from the forest margin. A total of five plots of 20m x 20m were laid in each habitat where data on mature trees, saplings and seedlings were collected. Soil samples were also collected for laboratory analysis. This study revealed that forest edge and intermediate were relatively similar but different from the forest interior in terms of tree species richness, diversity, evenness and structural composition respectively. The forest interior possessed higher species richness (25), diversity (2.93) and density of mature trees (89/ha), while the intermediate and edge possessed higher tree saplings (179/ha, 237/ha) and seedlings (611/ha, 358/ha). However, the soil physicochemical properties, except soil organic matter and organic carbon at 15-30cm, were uniform along the edge/interior gradient of the reserve. Since this forest edge and intermediate had higher regeneration potential than the forest interior, strict conservation measure should be put in place to protect the regenerated tree saplings and seedlings in this nature reserve.