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Grasslands of Umtamvuna Nature Reserve, KwaZulu-Natal : a description and recommendations for monitoring.Le Roux, Noel Peter. January 1995 (has links)
The main aim of this study was to classify and map the threatened coastal
grassland communities of the 3 257 ha Umtamvuna Nature Reserve (UNR) in
KwaZulu-Natal (30°07'30" to 300 11'05"E; 30°55'00" to 31°04'30"S).
Secondary aims were to relate past management and selected environmental
variables to community composition and to develop guidelines for monitoring.
Alpha diversity was measured using a Whittaker plot and revealed 119
species. A pilot study to test the efficiency of botanical techniques showed
that a point based technique (nearest plant method in a 20 X 20 m plot) was
efficient (52 minutes for recording 200 points), but recorded only 23% of the
species. By increasing the number of points to six hundred, 34% of the
species were recorded in 178 minutes; the same time was required to
randomly place 30 quadrats (50 X 50 cm), which revealed 80% of the
species. Tests for replicate similarity showed a high retrieval of internal
association (PS = 86%), using abundant species only and 100 points per plot.
The point based technique was thus efficient in detecting abundant species
and was acceptable for producing a classification, especially in this case
where a comprehensive species list already existed.
Indirect gradient analysis (TWINSPAN) identified six grassland communities.
An ordination using detrended correspondence analysis (DCA) contributed
towards the community classification and grazing and fire frequency gradients
were inferred from this ordination. Protea roupelliae communities were
common but did not influence grass species composition . Canonical ordination revealed that, of the eight environmental variables measured, 'distance from
the sea' strongly affected species distribution (r= 0.83).
Cost effectiveness was considered in the development of a monitoring
programme. Point based monitoring techniques favoured by sourveld
researchers in KwaZulu-Natal were found to be inefficient, particularly for
studies requiring the measurement of both species richness and community
composition. Randomly located 100 X 100 cm quadrats, located in selected
sites which represent previously identified communities, was more efficient.
This study contributed towards a refinement of information on the grassland
communities of KwaZulu-Natal and supported the use of point data for the
classification of grasslands not previously studied. It also demonstrated that
point based techniques were not suitable for meeting all grassland monitoring
requirements. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1995.
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A synfloristic comparison of Oribi Gorge and Umtamvuna Nature Reserves.Meter, Edna Beatrice. January 1998 (has links)
Climatic oscillation during the Quaternary resulted in fragmentation of
once more continuous ancient floras and a series of invasions of different
floras into the Pondoland Centre in response to climatic change, with some
elements invading more than once. This implies both a temporally complex
and a floristically complex origin for the extant flora of the Centre. Data
derived from analysis of the melange of extant floristic elements in the
Pondoland Centre is presented in support of this hypothesis. A synfloristic
comparison of Oribi Gorge (OGNR) and Umtamvuna Nature Reserves (UNR)
is the basis for this study.
A comparison of the species lists generated for OGNR and UNR
reveals that 24% of the 1514 angiosperm species are shared. The familial
composition of the reserves is similar, with eight of the ten most diverse
families contributing a similar proportion of species to the respective floras,
with the exception of Acanthaceae. The ten most diverse families comprise a
comparatively small proportion of the respective floras; this is indicative of
high diversity over long geological periods, i.e. of refugia. Analysis at the
generic level revealed similar consistancy between the two gorge floras.
Approximately 4% of the UNR species and 2.3% of OGNR species are
Pondoland Centre endemics. Approximately 40% of the endemic species are
shared by the gorges. Data reveals that both palaeoendemic (predominantly
woody, forest taxa) and neoendemic (predominantly herbaceous or
suffrutescent, grassland taxa) species occur. The Pondoland Centre is thus a
refugium for species trapped on the Msikaba Group sandstones as a result of
climatic oscillation during the Quaternary, and a centre of neoendemism.
OGNR and UNR floras include Cape, Afromontane and tropical
elements (11.3%, 2.8% and 19.1% respectively for OGNR and 16%,3.4%
and 15.3% respectively for UNR). Seventy - two percent of Afromontane
species are shared, indicating a relatively recent invasion(s) and lor the
relative proximity of the gorges to the Afromontane flora. The lower species
overlap in the Cape element (39.2%) of the two gorges implies that the
invasion of the element is ancient, with subsequent extinction of many of the
taxa from OGNR in response to climatic change. It is also possible that this
invasion was initally less successful; fewer species found refuge in OGNR.
The tropical element comprises the largest proportion of the flora in both
gorges and many (ca. 50%) of the species are shared. The degree of species
overlap indicates that the invasive flora was either initially more similar or that it is tess prone to extinction. The level of overlap could also suggest that the
invasion was more recent than that of the Cape taxa. The tropical element is
larger in OGNR and the Cape element is larger in UNR. This is partly due to
the gorges' respective proximities to the tropical and Cape floras. This trend
is echoed in the endemic data.
iv
The conservation status of the endemics and of the Pondoland
vegetation types is established and recommendations for further research are
made. The data support the establishment of a larger UNR, the maintenance
of both Umtamvuna and Oribi Gorge as formal nature reserves and the
establishment of a new reserve (or reserves) within the Pondoland Centre. / Thesis (M.Sc.)-University of Natal, Pietermarizburg, 1998.
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