Grasslands of the World.pdf - Disasters and Conflicts - UNEP

Grasslands of South Africa 115
with the tools to efficiently remove large quantities of aboveground standing
biomass. This approach may have been useful in the grasslands where research
had been carried out to show that grass species composition could be changed
by applying rotational grazing . However, this has had some very serious
consequences in the thicket biome , where succulent shrubs such as Portulacaria
afra have been completely removed from the landscape and do not regenerate
after severe defoliation (Stuart-Hill and Aucamp, 1993). In the savannah biome,
there is clear evidence of continuing woody encroachment by a wide range of
shrub species, including Acacia karroo, A. mellifera , Dichrostachys cinerea ,
Rhus undulata and Rhigozum trichotomum. Researchers suggest that this is
largely due to the removal of competitive grass species by herbivory, although
alternative hypotheses are suggested.
Maintenance of production and productivity
Following on the thinking of J.C. Smuts, who spear-headed rangeland
conservation initiatives in South Africa , Davies (1968) suggested that a holistic
approach is needed whereby plant, soil and animal influences are studied
as controllable parts of the environment. Savory (1988) further embellished
on this approach, coining the term Holistic Resource Management , which
embodied principles that were contrary to the conventional thinking amongst
range scientists (Clayton and Hurt, 1998). Savory (1988) encouraged ranchers
to employ non-selective grazing by maintaining large, mixed species – herds
that would intensively use a restricted area until the standing biomass had
been severely reduced, thereby eliminating competition among species. This
area would then receive a long rest, whereupon herbivores would return.
Numerous commercial graziers in South Africa have been encouraged to
follow this thinking, with no formal scientific debate being entertained on the
success of the approach. Vorster (1999) provides a convincing argument for
discouraging ranchers from pursuing this approach without careful assessment
of the rangeland resource.
Strategies for maintaining and optimizing aboveground grass production
include rotational grazing and resting; control of woody encroachment ; provision
of winter pastures in the cool, mesic regions where forage quality declines
in winter; and supplementary feeding on cultivated lands. In beef production
systems , livestock are finished in feedlots where maize provides the major feed
element. In these systems , production costs are determined by the international
maize price.
Priorities for the development of programmes and research
The National Department of Agriculture , in cooperation with ARC-RFI,
ARC-ISCW and CSIRO-Environmentek, is the key institution dealing with
forage resources . The Directorate of Land and Resource Management in the
National Department of Agriculture and Land Affairs is responsible for the