Woodland Conversion by Elephants in Africa: The Search for Causal Factors, Processes, Mechanisms and Management Strategies

Abstract

The impacts of elephants on woodlands have triggered concerns that elephants were converting woodlands to grasslands in African savannas leading to the loss of biodiversity. Therefore, the objectives of the study are to identify the causes, processes and impacts of woodland conversion by elephants and thereby propose a guideline for formulating management strategies. The study is conducted through reviewing published documents on elephant-woodland interaction, factors, mechanisms and processes of woodland conversion to grasslands and impacts on biodiversity have been identified. The study reveals that: 1) the large nutritional and energetic requirements by elephants and high elephant population densities are two driving forces that may cause elephants to convert woodlands to grasslands; 2) the process of woodland conversion is not just elephant-tree interaction, but usually included other agents such as fires, droughts or other herbivores. Woodlands are converted to grasslands or scrublands because elephants, fires, droughts and other herbivores prevent recruitment of tree to larger class sizes and regeneration of seedlings of woody plants; 3) whereas there are few studies that support biodiversity decline due to impacts of elephants on woodlands, there are studies that indicate woodland disturbance by elephants have benefited and increased diversity of other species. It is concluded that woodland disturbance by elephant is not always detrimental to biodiversity, but may create heterogeneity and suitable habitats for other species. In formulating management strategies, considerations must be made to elephant densities, other agents that interact or work with elephants in woodland conversion and the benefits of woodland changes to biodiversity due to elephants.