Process and drivers of vegetation change in African drylands : a case study of Yankari Game Reserve

• Main Author: Fada, Salamatu J.
• Published: Bangor University 2015
• Subjects: 333.95
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.690696

Despite the large quantity of research on the projected impacts of environmental drivers of change, relatively little is known about the changes in the West African savannah woody vegetation and their drivers. Understanding processes that operate and long term impact of drivers of vegetation change, acting individually or in combination, is vital to enable future mitigation through conservation practices to be successful. This thesis assessed the processes and drivers of vegetation change in the West African savannah, (with particular focus on the role of herders and their livestock) aiming to develop mitigation strategies to increase ecological resilience of the region, using the Yankari Game Reserve of Nigeria (Yankari) as a case study. This study is interdisciplinary, drawing on ecological (tree and shrubs inventories), geospatial (GIS and remote sensing techniques) and social – cultural (focus group discussions, questionnaires, and observations) approaches to collect and analyse relevant data to explore the study questions. Overall, it was found that the woody vegetation of Yankari has changed over time, showing general increase in species of Combretacaea family and decline in fodder species. Additionally, it was found that high variability in annual rainfall, prevalence of droughts, fire scars, prevalence of, and increase in human activities at the boundary of Yankari and 2013 satellite image showed that encroachment has extended into Yankari. Fodder s are harvested in Yankari but the extent of harvest varies by species. (Afzelia africana and Balanites aegyptiaca are severely harvested). Statistically significant relationships were found between core - boundary distance and the harvest rates of A. africana (P = 0.0001), and also, distance impacts significantly on recruitment of fodder treess in Yankari. The herders in Yankari inconsistently reported on the trends in their livestock but had clear knowledge of the preference and availability of fodder trees in their surroundings. Additionally, the study found out that many Fulani and their livestock undertook major migrations to the local communities in the 1980s and 1990s. Herders are aware of the decline in the abundance of fodder trees and have devised temporary migration as a strategy to cope with the situation. This study has provided quantitative evidence of current threats to West African savannah systems. It has also highlighted areas for further investigation as well as showed the need to initiate conservation strategies that will be beneficial for both the local communities as well as the conservation goals for Yankari.