Mapping and quantifying the impact of grazing around water points in a small semi-arid savaana game reserve
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Date
2011-06-24
Authors
Seitlhamo, Wilfred
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Abstract
The widespread provision of water points in protected areas in semi-arid savannas has supported
associated increases in cumulative grazing pressure. This study addresses the management
implications of artificial water provision which causes the development of grazing gradients of
increasing herbivore impact at artificial water point sites. The aim of the study was to map and
quantify the impact of grazing and trampling at water points sites in a 4 600 ha sized semi arid
savanna game reserve (Mafikeng Game Reserve in the North West Province).
Aerial photographs and SPOT imagery were used to identify the extent of the sacrifice
zone for the period before the reserve was established (1980), and after establishment (2003 and
2009). To quantify the herbaceous species, relative percentage frequency and composition, the
frequency of occurrence of species at water point sites was measured along four 100 m transect
following cardinal directions (north, east, south, west). Furthermore, Landscape Function
Analysis (LFA), which uses indicators that can be assessed rapidly to determine the functional
status of the rangelands, was applied. The landscape zones or cover types were related to 10
distance categories within a 100 m transect.
The results indicate the increasing extent of the sacrifice zone since the provision of the
artificial water points. The water points that are situated away from the river were characterized
by Increaser II species. Increaser I and Decreaser species characterized water points which are
situated along the river. Species composition was influenced by environmental variables such as
soil type and depth and the spatial location of water points in relation to natural water source.
The results of the study suggest changes in plant composition and soil cover that are probably
related to accumulated long-term loss of herbaceous vegetation cover around water points, with
special emphasis on water points that are situated away from the natural water source in the
central part of the reserve. This part of the reserve attracts higher concentrations of animals
probably due to the water points, which causes loss of herbaceous vegetation.
In order to minimize degradation of the areas surrounding water points in the central part
of the reserve, the rotational opening and closing of water points situated away from the river
should be explored, based on the system change, to allow vegetation recovery. Also, the nonoperating
water point near the natural source should be opened in an attempt to attract animals to
underutilized areas, to allow uniform desirable utilization of the entire reserve, taking the
reserve’s objectives into account.