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

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Grasslands of the world
is important to encourage growth of other more palatable and valuable forage
grasses, such as Cynodon dactylon , Panicum maximum and Setaria sphacelata
(Herlocker, 1999).
Loudetia species are often found mixed with Hyparrhenia spp. and
Themeda triandra in open grassland on shallow, rocky, sandy soils. They provide
late-season grazing for livestock (Rattray, 1960) but have low palatability
(Skerman and Riveros, 1990). Although Herlocker (1999) did not consider this
a vegetation type per se, and Rattray (1960) only considered this as a grassland
type for Uganda, Loudetia is widely distributed in rangeland ecosystems in
Tanzania , Kenya and Ethiopia, but is never the dominant species. The most
common species in the region is Loudetia simplex , which shows considerable
variability in morphology in Ethiopia (Phillips, 1995). However, the genus has
not been widely studied due to its low economic importance.
The highland areas of eastern Africa cover about 80 million hectares of
Ethiopia, Kenya and Uganda. Exotheca abyssinica grassland is common on
poor waterlogged soils in high altitude areas of eastern Africa, especially on
the seasonally waterlogged vertisols, of which there are 12.6 million hectares
alone in Ethiopia (Srivastava et al., 1993). This species is closely related to
Hyparrhenia and is often found growing in association with Themeda triandra
. E. abyssinica has tough leaves and low nutritive value (Dougall, 1960),
providing good grazing while young but quickly becoming tough and unpalatable.
Setaria incrassata and S. sphacelata are also common grassland species
found in Acacia woodland up to 2 600 m altitude on the vertisols of Uganda,
Sudan and Ethiopia (Rattray, 1960). S. incrassata is a very variable species, with
morphotypes varying in plant robustness, bristles, and number and density of
spikelets (Phillips, 1995). It is closely related to S. sphacelata, which is also a
very variable species, allowing selection of a range of cultivars from Kenyan
ecotypes that vary in frost tolerance, maturity, pigmentation and nutritive value
(Skerman and Riveros, 1990). Both S. sphacelata and S. incrassata are palatable
grasses that withstand heavy grazing.
Pennisetum grassland areas can be classified as two types : high altitude
grasslands of P. clandestinum and savannah grassland of P. purpureum (Rattray,
1960; Herlocker, 1999). Although belonging to the same genus, these species
are morphologically and ecotypically very distinct, and have very different distribution
and ecological niches. Both species are indigenous to eastern Africa ,
with high economic importance, and are cultivated in many other parts of the
world.
P. clandestinum is a prostrate stoloniferous perennial that is widely distributed
in areas from 1 400 m to over 3 000 m in Kenya, Ethiopia, Tanzania
and Uganda. Its common name, Kikuyu grass , derives from the highlands
of Kenya, where it is abundant, being named after the Kikuyu ethnic group
of central Kenya. It shows wide adaptability to drought , waterlogging and
occasional frosts (Skerman and Riveros, 1990). It is highly digestible, palatable,