Land degradation continues despite greening in the Nigeria-Niger border region

Jörg Kaduk,Heiko Balzter,Yahaya Z. Ibrahim

doi:10.1016/j.gecco.2018.e00505

Abstract

Recent satellite observations of the West African Sahel have shown an increase in vegetation greenness. However, many of these studies have little or no field validation to ascertain the actual environmental conditions on the ground. Here, we assess the condition of woody vegetation species in relation to land degradation processes and examine the conditions and patterns of their changes in the Nigeria-Niger border region in West Africa. Indigenous knowledge, a botanical survey, field observations and trend analyses were used to evaluate ecological changes in the area. A survey of 70 respondents which were selected using purposive sampling is presented i.e. 10 respondents each from seven villages, and focus group interviews were conducted to ascertain the condition of woody vegetation changes. The results show that despite the overall increase of vegetation greeness observed from remote sensing, the diversity and density of indigenous woody vegetation species is declining throughout the area. Nearly 80% of all the indigenous plant species of the region such as Borassus aethiopum, Ficus thonningii and Ficus thonningii have either completely disappeared or migrated southward where climatic conditions are more favourable. Therefore, the evidence suggests that land degradation is ongoing in the region and that local knowledge should be integrated in ecological resource management, especially at the local level, where locals rely on woody trees for food, income and fuelwood, so that plant species at risk of extinction can be preserved and where possible regenerated for conservation and sustainable use of the woody plant species in the region.

Highlights

Environmental change and land-use patterns of human activities in sub-Saharan West Africa have produced perilous environmental conditions over the past decades
The last three decades have been characterised by a controversial discussion of the hypothesised greening of the West African Sahel and the possible reversal of desertification and land degradation in the region
This study has shown that tree species degradation is still ongoing in the Nigeria-Niger border region contrary to the 30year greening trend observed from remote sensing studies

Summary

Introduction

Environmental change and land-use patterns of human activities in sub-Saharan West Africa have produced perilous environmental conditions over the past decades. The last three decades have been characterised by a controversial discussion of the hypothesised greening of the West African Sahel and the possible reversal of desertification and land degradation in the region. Some authors have argued that the (re)greening of the Sahel is a recovery process of vegetation from a long period of degradation; thought to be associated with an increase in rainfall (Nicholson, 2005; Eklundh and Olsson, 2003). Others acknowledge the rainfall increase but suggest that changes in land use and land management practices are the major driving force, with other important factors such as cultural issues, ownership of trees on farmlands, forestry laws and economic opportunities contributing to the greening (Reij et al, 2009)

Results

Discussion

Conclusion