Rangeland Degradation in a Semi‐Arid Communal Savannah of Swaziland: Long–Term DIP‐Tank Use Effects on Woody Plant Structure, Cover and their Indigenous Use in Three Soil Types

Abstract

AbstractThis study investigated dip‐tank use effects on the surrounding woody vegetation cover and encroachment level and on their indigenous utilisation. Eight dip tanks, three in deep‐pale‐brown old alluvium sandy, three in deep‐yellow‐red loamy, and two in rock outcrops and stony ground soils, were selected. Woody vegetation survey was conducted at 50, 100, 150, 300, 500, 700 and 900 m from each dip tank. Dichrostachys cinerea and Acacia tortilis were the dominant woody species in all areas. In deep‐pale‐brown old alluvium sandy soils, D. cinerea density was affected by distance from dip tank up to 150 m (p = 0∙03), where the density of A. tortilis was low (p = 0∙02). In deep‐yellow‐red loamy soils, the lowest and highest (p = 0∙05) D. cinerea densities were recorded at 150 and 700 m from the dip tank, respectively. Inconsistent results were found on the piosphere formation of total woody density and cover. Nevertheless, large areas surrounding the dip tank had a bush cover of >50 per cent. This study concluded that there was heavy bush encroachment around many dip tanks despite the harvest for woody species by the community. Therefore, there is a need to develop a sustainable and integrated bush control programme that provides conservation plans for species valuable for food and livelihood security. The programme should be based on communal participation and consider shifting of old dip‐tank sites and protecting the areas from disturbance. Indiscriminate (burning) or selective (manual) or a combination of the two bush control methods may be initially recommended after a rest period of at least two consecutive growing seasons. Copyright © 2013 John Wiley & Sons, Ltd.