Long-term monitoring of elephant impact on the woody vegetation in the Tembe Elephant Park, South Africa
The African Elephant is a key component of the savanna ecosystem. They contribute to the generation of habitat for smaller vertebrates, as well as invertebrates, by the breaking of branches or uprooting of trees. Elephants also play a role in seed dispersal, germination and sapling recruitment. A...
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University of Pretoria
2013
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| Online Access: | http://hdl.handle.net/2263/30940 Potgieter, M 2012, Long-term monitoring of elephant impact on the woody vegetation in the Tembe Elephant Park, South Africa, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/30940> http://upetd.up.ac.za/thesis/available/etd-06212013-125314/ |
| Summary: | The African Elephant is a key component of the savanna ecosystem. They contribute to the
generation of habitat for smaller vertebrates, as well as invertebrates, by the breaking of
branches or uprooting of trees. Elephants also play a role in seed dispersal, germination and
sapling recruitment. All these functions are advantageous to the ecosystem if the elephant
population size is acceptable for the size of the reserve and the amount of available forage.
The Tembe Elephant Park covers an area of 30 013 ha and is situated in northern KwaZulu
Natal. This reserve has a diversity of vegetation types and is part of the Maputaland Centre
of Plant Endemism and the Maputaland-Pondoland-Albany Hotspot of Biodiversity. Elephant
numbers in the park are currently high and the elephant population is still increasing. This is
threatening, especially to the endemic Sand Forest communities within the park.
The extent of elephant impact in Tembe Elephant Park, South Africa, was investigated and
compared to data collected six years prior to the current study. Elephant impact was
determined in 44 transects within nine communities across the park. Percentage canopy
removal was calculated for the woody individuals found in sites and with this data the
targeted size classes and species could be identified. The preferences of elephants for
specific woody species were determined by three electivity indices.
Elephant utilisation in Tembe Elephant Park, as reflected by percentage canopy removal,
increased since 2004 as the elephant population increased. Communities that experienced high values in 2010 of elephant utilisation were the Closed Woodland 1, Mature Sand
Forest, Open Woodland 1 and the Closed Woodland 3. Not only did the actual canopy
volume removed by elephant increase with approximately 57%, but the total canopy volume
available for browsing decreased extensively since 2004.
The size classes targeted by the elephants remained approximately the same from 2004 to
2010 although the 2010 results showed that elephant canopy removal percentage increased
in the large size classes. This was expected as elephants target individuals with large stem
diameters.
A change in the selection for woody species by elephants was clear, but the change in
species preference made future projections of canopy removal problematic. Elephants seem
to utilise a species at extreme levels until the species is almost extirpated, then they move
onto the next target species. This routine is evident in the results as highly preferred species
in 2004, with high canopy volumes available and removed, had low canopy availability and
electivity ratios in 2010, consequently the elephants moved on from these species as
individuals became scarce.
It was clear that the structure of individuals, populations and communities were being
altered, selected species were facing extirpation and composition of communities was
changed through the browsing manners of elephants. Management actions should be
implemented to prevent irreversible damage to the vegetation and to conserve the woody
species currently under threat. === Dissertation (MSc)--University of Pretoria, 2012. === Plant Science === MSc === Unrestricted |
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