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

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Grasslands of the world
subsistence cultivation were abandoned after a few years, due to crop destruction
by wildlife and highly variable yields linked with climate variability. In
the Tanzanian part of the ecosystem, land cover changes were less pronounced.
No conversion for large-scale farming occurred; most land cover changes were
either expansion of smallholder cultivation or natural succession in rangelands.
Extensive areas of cultivated land (subsistence to medium-scale agriculture)
were found in the unprotected lands, right up to the border with the protected
areas west of Serengeti and southeast of NCA. In the NCA and the Loliondo
Game Controlled Area, about 2 percent of land cover changes were attributed
to smallholder impact over the past 20 years. In the NCA, cultivation is regulated:
only hand-hoe cultivation is allowed and fields are small and scattered. In
the Loliondo, no such restrictions are in place, but the area is very inaccessible,
so the lack of opportunities to export the crops outside the area effectively
controls the extent of cultivation.
The conversion of rangelands to agriculture has had a serious impact on the
wildebeest population in the Kenyan part of the Serengeti-Mara ecosystem .
The population declined drastically over the past twenty years and is currently
fluctuating around an estimated population of 31 300 animals, which is about
25 percent of the population size at the end of the 1970s. Fluctuations in the
wildebeest population in the Kenyan part of the Serengeti-Mara ecosystem,
over the last decades, have been correlated strongly with the availability
of forage during the dry and the wet seasons (Serneels and Lambin, 2001).
Expansion of large-scale mechanized wheat farming in Kenya since the early
1980s has drastically reduced the wildebeest wet-season range, forcing the
wildebeest population to use drier rangelands or to move to areas where
competition with cattle is greater. The expansion of the farming area has not
influenced the size of the total cattle population in the Kenyan part of the
study area, nor its spatial distribution. The much larger migratory wildebeest
population of the Serengeti, in Tanzania , did not decline at the same time as
the Kenyan population but is also regulated by food supply in the dry season
(Mduma, Sinclair and Hilborn, 1999). Around the Serengeti, in Tanzania, land
use changes are much less widespread, occur at a lower rate and affect a much
smaller area compared with the Kenyan part of the ecosystem. Moreover,
land use changes around the Serengeti have taken place away from the main
migration routes of wildebeest.
Protected areas and local land use: source of conflict in Tanzania
Savannah ecosystems are well represented in African protected area networks
(Davis, Heywood and Hamilton, 1994). In Tanzania , very large tracts of
savannah have been set aside for conservation , partly because these rangelands
support the most diverse assemblage of migrating ungulates on earth (Sinclair,
1995). However, there are few resources to manage these conservation areas
effectively and the rural populations surrounding them are among the poorest