A plant ecological survey of the Umfolozi Game Reserve, Zululand.
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Date
1972
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Abstract
A landscape unit approach based on use of
airphotos was used for investigation of Deciduous Acacia
Woodland in the Reserve. The approach was useful for
indicating that a quantity of as few as 531 samples could be
suitable for sampling woody vegetation over the large, 493
kmĀ² area, and for showing where the samples might
advantageously be distributed. Use of the approach
minimised the extrapolation of community boundaries for
mapping purposes.
Normal association analysis of the samples
revealed the nine woody consociations present and provided
quantitative data on species constancy and fidelity. These
data were used towards explaining low levels of homogeneity
within consociations, as well as some close floristic
similarities found between consociations. The successful
emergence of a species to dominance in a consociation was
ascribed to the presence of a particular, described soil
series or rock substrate. The distribution pattern of the
consociations resembled a soil-vegetation catena on the
landscape. The consociations were grouped into defined
physiognomic categories of Open, Closed and Riverine Woodland
Associations that were distributed according to three soil
associations. The effects of soil factors, fire and the
biota on physiognomy, notably secondary thicket encroachment,
were discussed; and the relationship between climate and
phenology was mentioned.
A quantitative description of the grass communities
based on normal analysis of stratified sample data revealed
a retrogression whereby climax grasses are being replaced by
mid-seral and pioneer grasses. The retrogression was
ascribed to selective grazing by an increasingly large biomass
of enumerated, indigenous herbivores. Some of the management
recommendations offered were based on empirically calculated
estimates of the weights of dry grass required annually by
the grazing animals.
Copies of topography, place names, geology, land surface and vegetation maps are provided. The text is
supplemented by check lists of plants and animals recorded,
by eight figures, 33 tables and 54 photos.
Description
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1972.
Keywords
Plant ecology--KwaZulu-Natal., Theses--Botany.