Two management blocks were set aside in Umfolozi Game Reserve
(UGR) to compare different management approaches. In one, the
non-cull block, a noninterventionist policy was followed and no
large mammals were removed, while the other, the cull block was
subjected to the same game removal treatment as the remainder of
the reserve. The main objectives of this study were to determine
the relationships between vegetation, soil surface variables and
both soil loss and rainfall run-off, to derive predictive models
for run-off and soil loss based on vegetation and soil surface
variables, to determine the relationship between different levels
of soil erosion and the production potential of soils, and to
determine the relationship between different levels of soil
erosion and herbaceous species diversity.
Rainfall simulator trials and natural run-off plots were used to
collect quantitative data on soil loss and run-off. Bivariate
scattergrams showed that the relationship between soil surface
and vegetation variables plotted against soil loss was
curvilinear. "Susceptibility to erosion" showed the highest
positive correlation, and "surface cover" the highest negative
correlation with soil loss. The relationship between annual
run-off and both the soil surface and vegetation variables was
also curvilinear, with "soil capping" showing the highest
positive and "litter cover" the highest negative correlation with
run-off. Using multiple regression analysis it was found that
"susceptibility to erosion" and
predictors of annual soil loss.
"surface cover" were the best
"Soil capping" and "percentage
contribution of
run-off.
forbs" were the best predictors of annual
No clear relationship between either soil loss and stocking rate,
or run-off and stocking rate was apparent in the two experimental
blocks, and the differences in soil loss and run-off could not be
explained by differences in stocking rate alone. There were
however defects in the experimental design which invalidated the assumption that the stocking ~ate diffe~entia1
management blocks would inc~ease with time.
between the two
Because of the above deficiency, an a1te~native study a~ea on the
weste~n bounda~y fence, which allowed fo~ pai~ed sampling sites
on eithe~ side of the fence, was chosen. Ge~lach t~oughs we~e
used to measu~e soil loss. The g~eatest va~iabi1ity in soil loss
was explained by the position of the plots on the slope ~athe~
than whethe~ the plots we~e in UGR o~ in adjacent KwaZu1u.
Simi1a~ly, diffe~ences in topog~aphy, ~athe~ than diffe~ences in
1anduse, exe~ted an ove~~iding effect on A-ho~izon depth, he~bage
accumulation and g~ass species ~ichness. Conside~ing the ~esu1ts
obtained, the opinion that a noninte~ventionist policy would lead
to a decline in vegetation p~oductivity and to a 10ng-te~m
~eduction in species dive~sity appea~s to be unfounded.
Finally, based on the data collected and on a ~eview of cu~~ent
scientific 1ite~atu~e, changes to the Natal Pa~ks Boa~d soils
policy and objectives a~e suggested, and the objectives a~e
t~ans1ated into ope~ationa1 management goals. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1988.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/10907 |
| Date | January 1988 |
| Creators | Venter, Johan. |
| Contributors | Tainton, Neil M., Schulze, Roland E. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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