Anthropogenic Pressure on Tree Species Diversity, Composition, and Growth of Balanites aegyptiaca in Dinder Biosphere Reserve, Sudan.

Elmugheira M I Mohammed,Anna C Treydte,Patrick A Ndakidemi,Elhag A M H

doi:10.3390/plants10030483

Abstract

Anthropogenic disturbances, such as illegal harvesting and livestock browsing, often affect natural forests. However, the resulting tree species diversity, composition, and population structure have rarely been quantified. We assessed tree species diversity and importance value indices and, in particular, Balanites aegyptiaca (L.) Del. population structure, across 100 sample plots of 25 m × 40 m in disturbed and non-disturbed sites at the Dinder Biosphere Reserve, Sudan, from April 2019 to April 2020. We found that the tree species diversity in non-disturbed sites was more than double that of disturbed sites (p < 0.001, T = 32.6), and seedlings and saplings comprised more than 72% of the entire tree population (F2,48 = 116.4, p = 0.034; F2,48 = 163.2, p = 0.021, respectively). The tree density of B. aegyptiaca in the disturbed site was less than half that of the non-disturbed site (p = 0.018, T = 2.6). Balanites aegyptiaca was seven times more aggregated in disturbed sites compared to more regularly spaced trees in non-disturbed sites (T = 39.3 and p < 0.001). The poor B. aegyptiaca population status of the disturbed site shows that the conservation of this vulnerable species is essential for a sustainable management and utilization scheme.

Highlights

Life Sciences and Bioengineering, The Nelson Mandela African Institution of Science and Technology, Department of Forest Management Science, Faculty of Forest Science and Technology, University of Gezira, Wad Medani P.O
The density of the seven most common mature trees (F6,406 = 20.3, p = 0.001), saplings (F6,406 = 19.1, p = 0.011), and seedlings (F6,406 = 17.3, p = 0.021) was significantly different between the non-disturbed and disturbed sites, with generally higher densities in the non-disturbed sites (Figure 1). This significant difference was mainly visible for Combretum hartmannianum Schweinf, B. aegyptiaca, Anogeissus leiocarpus (DC.) Guill and Perr., and Lannea fruticosa (Hochst.) Engl tree species, while Acacia seyal Del., showed a contrasting pattern, having higher densities in disturbed sites (Figure 1)
We found that more than 85% of the tree species in the disturbed site have a poor regeneration status, and some species such as T. indica were only found in their mature stage

Summary

Introduction

We assessed tree species diversity and importance value indices and, in particular, Balanites aegyptiaca (L.) Del. population structure, across 100 sample plots of 25 m × 40 m in disturbed and non-disturbed sites at the Dinder Biosphere Reserve, Sudan, from April 2019 to. The ecological support of the forests can be observed through its hydrological functions, carbon sequestration, sites of recreation, biodiversity protection and conservation [1,4,5,6]. Their economic contribution includes the provision of food, timber and non-timber products, fodder for livestock, medicinal extracts, and shelter for humans and animals [2,7,8]. In sub-Saharan countries and the Sahel region, the recent and rapidly increasing over-exploitation and other human disturbances may strongly degrade the dynamics of these resources [11,12]

Results

Discussion

Conclusion