The significance of the woody component of semi‐arid savanna vegetation in relation to meat production

Abstract

In many semi-arid savanna areas of southern Africa extensive beef ranching is the main form of land use. Cattle prefer to graze rather than to browse and the woody component of the vegetation is therefore normally underutilized. Beef ranching will remain important but it is suggested that the use of domesticated browsers such as goats and eland in conjunction with cattle would achieve better overall utilization of the vegetation and prevent bush encroachment. Increased meat production would also be expected. However, not enough is known about the effects on the vegetation of stocking with both browsing and grazing animals to allow for the definition of clear management policies. Further information is needed about the woody plant standing crop and seasonal production in various vegetation types, woody species composition, browse quality and availability, the effects of utilization on woody plants, carrying capacity, the management principles for sustained woody foliage production, and the detailed relationships within the 'browse-grass-browser-grazer' complex. The effects of manipulation of the woody component on the quantity and quality of herbaceous feed and on ecosystem stability must also be considered. It is suggested that research should be within the framework of cattle ranching and aimed at maximum sustained meat production. UITTREKSEL In menige ariede en semi-ariede savanne gebiede van suidelike Afrika is ekstensiewe beesboerdery die vernaamste praktyk vir die benutting van die natuurlike plantegroei. Beeste verkies gras en dit het tot gevolg dat die boskomponent onderbenut is. Beesboerdery sal egter die vernaamste vorm van boerdery in die bosveldgebiede bly. Dit is voor die hand liggend dat deur gebruik te maak van stmikvreters beter benutting van plantegroei asook beheer oor bosindringing verkry kan word, 'n Direkte gevolg van so 'n stop sal 'n verhoging in vleisproduksie per eenheid weiding tot gevolg hê.Bokke en elande besit die vermoë om bosplantegroei te benut. Min is egter bekend oor die moontlikheid van met beeste en ander plantvretende diere gelyktydig te boer. Verdere inligting oor die volgende aspekte betreffende die produksie-moontlikhede van die boskomponent moet ingewin word. Hierdie aspekte sluit in seisoenale produksie, spesiesamestelling, weidingskwaliteit en beskikbaarheid, benutting en die effek van benutting, drakrag, beginsels van bestuur vir gehandhaafde blaarproduksie en die presiese verwantskap binne die kompleks van blare en gras asook tussen die struikvreters en weidiere. Oorweging moet ook geskenk word aan die effek wat die manipulasie van die boskomponente op die bosgemeenskap en die stabiliteit van die ekosisteem sal hê. Navorsing moet dus binne die raamwerk van beesboerdery beplan word en moet as doelstelling hê, maksimum vleisproduksie per eenheid weiding.

Micro-site effects of trees and shrubs in dry savannas

“…These are: nitrogenfixation, the vertical nutrient pump and reduced leaching due to slower decomposition in the shade. This may explain the fact that, at some sites, the total herbaceous cover was higher with low tree cover as compared to treeless savanna (Kelly 1977;Sanford et al 1982;Obot 1986). Also, the nutrient content of the total herbaceous layer has been found to be higher in tree savanna than in open grassland (Kennard & Walker 1973;Barnes 1979;Grossman, Grunow & Theron 1980;Stuart-Hill & Tainton 1989).…”

Veld management in the semi‐arid bush‐grass communities of the eastern cape

“…The added diversity provided by the presence of woody plants and browsing animals probably adds stability and resilience to the system (Walker and NoyMeir, 1979) relative to a simple grass-grazer alternative. In addition, the modifications to the soil nutrient pool and amelioration of the micro climate by woody plants Aucamp, 1980) may be beneficial (Charley, 1977;Kelly, 1977). The extent to which these advantages can be turned to economic gain depend largely on management.…”