Impacts of a mineral lick-centred land use system on woody vegetation cover in an East African Savannah (original) (raw)
2018, African Journal of Ecology
Evaluation of woody vegetation changes with distance from a salt crater was conducted in the semi-arid rangelands of southern Ethiopia. Data on live woody plants were collected over three seasons at 0, 1, 4, 6, 9 and 12 km from the salt crater. The density and diversity of woody plants differed significantly (p < .01) along the distance gradient. Six woody plant families were identified of which Fabaceae and Burseraceae were the dominant families. Acacia drepanolobium, Acacia nilotica, Commiphora africana and Acacia mellifera were among the severely encroaching woody species. There were high proportions of seedlings and saplings recorded closer to the salt crater showing a vigorous recruitment by woody plants. Woody plant encroachment along the 12-km transect ranged from a low to severe encroachment, which could be translated into poor rangeland condition. Changes in soil characteristics increased grazing pressure and sedentary settlement around the salt crater, and the breakdown of traditional institutions seems to be major contributing factors to these vegetation changes. We suggest that severely encroached areas could be improved through a combination of methods such as bush clearing, prescribed fire, browsing animals and proper grazing management. R esum e Nous avons r ealis e une evaluation des changements de la v eg etation avec la distance par rapport a un crat ere salin dans les etendues semi-arides du sud de l' Ethiopie. Nous avons r ecolt e des donn ees sur des plantes ligneuses vivant a 0, 1, 4, 6, 9 et 12 km du crat ere salin. La densit e et la diversit e des plantes ligneuses diff eraient significativement (p < .01) le long du gradient de distance. Six familles de plantes ligneuses ont et e identifi ees, parmi lesquelles les Fabaceae et les Burseraceae etaient les familles dominantes. Acacia drepanolobium, Acacia nilotica, Commiphora africana et Acacia mellifera comptaient parmi les esp eces ligneuses les plus gravement envahissantes. Il y avait de fortes proportions de jeunes plants et d'arbustes plus pr es du crat ere, ce qui montre un recru vigoureux de plantes ligneuses. L'envahissement des plantes ligneuses le long des 12 km de transect allait de faible a s ev ere, ce qui peut se traduire par un etat m ediocre de l'habitat. Les changements des caract eristiques du sol, une pression plus intense du pâturage et les installations permanentes autour du crat ere salin, ainsi que la disparition des institutions traditionnelles semblentêtre les principaux facteurs de ces changements de la v eg etation. Nous sugg erons d'am eliorer les zones les plus gravement envahies grâce a une combinaison de