Marloth Park Management Plan. - Nkomazi Local Municipality
Marloth Park Management Plan. - Nkomazi Local Municipality
Marloth Park Management Plan. - Nkomazi Local Municipality
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THE ASSESSMENT OF AVAILABLE BROWSE AND CALCULATION OF<br />
INTRODUCTION<br />
BROWSING CAPACITY<br />
In a vegetation type such as bushveld, it is of importance not only to estimate available<br />
grazing, but also available browse, as this component will contribute to the areas ecological<br />
carrying capacity. Browsers such as kudu Tragelaphus strepsiceros and intermediate feeders<br />
such as impala Aepyceros melampus melampus that utilise both graze and browse resources<br />
dominate herbivore populations on <strong>Marloth</strong> <strong>Park</strong>. Estimation of tree densities can<br />
furthermore, indicate areas of bush encroachment, where species are known for their invasive<br />
tendencies.<br />
In the early days of wildlife ranching, stocking rates were based solely on the forage, dry<br />
biomass requirements for cattle. Irrespective of their feeding behaviour wild southern African<br />
herbivores were stocked according to equivalences of Large Stock Units, based on their<br />
metabolic mass only. New conversion tables, which take different feeding behaviour and<br />
energy requirements of wild southern African ungulates, additionally to metabolic body mass,<br />
into consideration were only devised with the development of a technique to measure the<br />
available browse. With the advent of this technique a Browse Animal Unit was defined.<br />
Browsing capacity is defined as the number of Browse Animal Units that can be maintained<br />
in good condition in a certain area, without deterioration of the environment. A Browse<br />
Animal Unit was subsequently defined as the equivalent of a kudu Tragelaphus strepsiceros<br />
with a body mass of 140 kg, which browses exclusively. Several factors influence the<br />
browsing capacity. Not only the density of woody plants and their leaf production, but also<br />
the dominant browser population and their maximum browsing height, as well as the<br />
accessibility of the leaf material has to be taken into account. To consider these factors total<br />
browse is differentiated from available browse. Total browse encompasses all potentially<br />
edible woody plant material, whereas available browse includes only woody plant material<br />
available to the animals. For most browsers the maximum browse height is limited to 2 m,<br />
with the exception of giraffe Giraffa camelopardalis and elephant Loxodonta africana that<br />
can browse to a height of 5.5 m. Another factor is the species composition in each<br />
homogenous unit, as not all tree species are edible or selected by animals, and many trees<br />
develop mechanical and/ or chemical defence mechanisms such as thorns or tannins. The<br />
species composition affects the available browse, as the various species show differing<br />
phenology in the form of different patterns of leaf-emergence, flowering, fruiting and leaf-<br />
loss in the course of the year.<br />
© Ecological Associates/ <strong>Marloth</strong> <strong>Park</strong> 46