Fjölrit RALA - 05.12.1999, Blaðsíða 71

MlTCHAEL B.K. DARKOH
69
THE MID-BOTETl AREA - A
CASESTUDY
An area where desertification
has been intensively studied
in recent years is Mid-Boteti
(Figure 7), one of the most
remote parts of the country
(Arntzen et al. 1994, Chanda
1996, Ringrose et al. 1996,
Rampha 1996, Sefe et al.
1996). The area is located in
the Kalahari sandveld region
which has a low natural pro-
ductivity due to low rainfall
and poor sandy soils. It is
drained by the Boteti, an
ephemeral river which at
times flows during the dry
season, fed by water origi-
nating from Angola (via the
Okavango). The area is in-
habited mostly by poor pas-
toralists. Because of the nutri-
ent deficient sandy soils and
persistent seasonal and cycli-
cal drought, only a marginal
agricultural activity can be
sustained. Despite this, land
use pressure is relatively high,
as people have been attracted
to the area since historical
times, because of the availability of surface water and the absence of the tse-tse fly. In
recent decades, human pressure has rapidly increased to cause increasing resource
management problems, particularly during drought and in years when the river does
not flow (as has been the case in most of the last decade). The area has come to be re-
garded in recent years as one of the most degraded areas in Botswana (Ringrose and
Matheson 1978, Ringrose et al. 1996).
Desertification was found to occur at a significant rate in the Mid-Boteti area
(Arntzen et al. 1994, Ringrose et al. 1996). Symptoms which occurred or increased
since the 1970’s include: large areas of bare soils, recently formed sand dunes, the re-
moval of up to 2-3 cm of the topsoil through wind erosion, changes in the composi-
tion of vegetation, a high proportion of dead trees, a declining ground water table, in-
creasing salinity of wells, and a substantial reduction in wildlife numbers. Particularly
affected areas include the zone along the river, areas around villages and around bore-
holes, where pressure tends to be relatively high. Since the area has suffered no de-
cline in average rainfall during the past decades, resource depletion has been attrib-
160000
140000
120000
100000
J 80000
60000
20000
0
1975 1984 1994
Figure 6. Change in extent of area classified as 'degraded'
through non-drought period (1975), mostly drought (1984)
and the post drought recovery period (1994). (Source: Rin-
grose etal. 1997).