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Justus-Liebig-Universität Gießen (2011)

Communal rangelands in northern and central Namibia : the grazing and browsing resources and their users

Schneiderat, Ute

Titre : Communal rangelands in northern and central Namibia : the grazing and browsing resources and their users

Kommunales Weideland in Nord- und Zentralnamibia : Gras und Blattressourcen und ihre Nutzer

Auteur : Schneiderat, Ute

Université de soutenance : Justus-Liebig-Universität Gießen

Grade : Doktorgrade 2011

Résumé
The models and methods to detect carrying capacity in Southern Africa have not been tailored to communally managed rangelands. This study, carried out in the context of the BIOTA Southern Africa Project, investigates the rangeland resources, both grass resources for grazers (mainly cattle and sheep) as well as available leaf resources for browsers (such as goats), and the livestock management in two communal areas in semi-arid Namibia. In order to investigate to which extent land use has an impact on communal rangelands, and to estimate the quantity and quality of the forage resources for grazers and browsers, a detailed rangeland evaluation, designed with radial transects around the central water point, was carried out both during dry and wet season. Based on these results the grazing and browsing capacity of the entire communal areas was estimated, using BecVol (Biomass Estimates from Canopy Volume) to quantify the leaf biomass of bushes and trees. Mutompo is located in the north of Namibia (Kavango), with 14 households, keeping 197 cattle, 226 goats and 12 sheep, in a dry forest region of 3,800 ha. Okamboro (Ovitoto Reserve, Otjozondjupa), a community located in Central Namibia, consists of 29 households, and 941 cattle, 623 goats and 157 sheep graze on an area of 5,800 ha in the Acacia highlands. A restricted sacrificed zone around the water points was found, but regarding the entire areas, the natural resources were not degraded. Land use gradients were investigated for some grass parameters, especially in Okamboro. In Okamboro, other signs of long-term high stocking densities were detectable ; however, a drought situation in Okamboro might have overlapped with the real rangeland status, resulting in very poor biomass growth, and bare soil areas. The grazing pressure on rangeland was much higher in Okamboro (stocking density : 42 kg ha-1) than in Mutompo (stocking density : 15 kg ha-1), also due to twice the number of people that live in Mutompo than live in Okamboro. In addition, the land use history goes back further in Okamboro than it does in Mutompo. In Mutompo, the ongoing clearing of dry forest vegetation, in order to establish fields for cropping, destroys vegetation. The areas of higher impacts were focused on fertile soil areas, oriented along the former sand dune structure. The communal rangeland in Mutompo showed a potential for both, grazers and browsers. During the drought situation in Okamboro, browse was still available, but grazers theoretically needed to be reduced to a minimum level. Following these results, goat keeping should be extended – but goats do not have a prestige function.

Mots Clés : Weideressourcen , Namibia , kommunales Gebiet , Tragfähigkeit , Futteraufnahme , BecVol – rangeland resources , Namibia , communal area , carrying capacity , browsing , BecVol

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Page publiée le 17 janvier 2016, mise à jour le 8 janvier 2019