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

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Grasslands of the world
imagery to explore the extent of and trends in soil erosion, bush encroachment
and rangeland degradation . The directorate has supported the calibration of
NOAA AVHRR data for use in assessing trends since the launch of these
satellites in 1980, and is now funding research into using high resolution infrared
instruments (digital cameras and other high resolution sensors) to assess
range and landscape degradation at the farm and village scale. The problem
organism division continues to show interest in brown locusts, quelea control ,
woody weed encroachment (especially alien taxa such as Prosopis spp. ) and
alien weed control. The list of alien weeds is extensive , with some 197 taxa
being listed as declared weeds and invader plants (Henderson, 2001) and a
further 60 taxa being considered as proposed weeds (Henderson, 2001) and a
threat to range and water resources. The rangeland resources division funds
projects that assess the impact of different grazing management approaches
(e.g. continuous versus rotational grazing ) on rangeland. This is being carried
out in a network of replicated grazing trials throughout the country.
The Grassland Society of Southern Africa (GSSA) is the professional organization
representing the discipline. GSSA maintains a full-time secretariat for
its members, organizes annual congresses at localities around the subcontinent
and publishes a peer-reviewed journal (African Journal of Range and Forage
Science). The journal has been published since 1966, and about a thousand peerreviewed
articles have appeared.
Botanical research relating to rangeland is conducted by the National
Botanical Institute (NBI) of the Ministry of Environmental Affairs and
Tourism . NBI has focused on exploring the natural patterns and processes
driving vegetation status in the arid and semi -arid regions of the Nama-karoo
and succulent karoo biomes .
MANAGEMENT OF GRASSLANDS
In response to a decline in profit margins and negative sentiments associated
with domestic livestock production, there has been a marked increase in game
farming and ecotourism on commercial ranching areas. This is manifested in
the large numbers of game-proof fences erected on farm boundaries and the
removal of internal fences and stock watering points . This change has an impact
on the management of rangeland, as livestock can no longer be manipulated
and it is more difficult to apply rotational grazing . In commercial farming
operations, fire is used on many high-elevation rangelands to provide grazing
during the early growing season. Fire is used primarily by commercial ranchers
to remove low quality material remaining after winter and to encourage a flush
of short green grass in spring (see Plate 3.7).
Development of techniques for the rehabilitation of grasslands
The processes of degradation in arid and semi -arid rangelands are poorly
understood and only recently have some researchers provided a conceptual