Thesis (PhD (Botany and Zoology))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: The worldwide movement of biota is of substantial concern for the conservation of
biodiversity. The movement of species takes place at three different scales. These are
translocations of indigenous species within their natural distribution ranges, the
translocation of species outside their natural distribution ranges within geopolitical
boundaries (i.e. extralimital introductions) and the translocation of species outside
geopolitical boundaries and their natural distribution ranges (i.e. extraregional
introductions). Ungulates are extensively translocated at each of these scales and each
scale of translocation is expected to have different impacts on biodiversity. Ungulates
are translocated for conservation purposes such as reintroducing species to places
where they have previously gone extinct and to mitigate inbreeding in small, isolated
populations. Ungulates are also extensively translocated for economic and
recreational reasons, such as for sport hunting. Translocations for sport hunting
include indigenous, extralimital and extraregional species. Concerns for translocations
of indigenous species are largely for the loss of genetic diversity through the mixing
of genetically distinct populations, and concerns for extralimital and extraregional
translocations are for impacts on indigenous biodiversity such as through herbivory,
competition, hybridization and disease transmission. This thesis investigates the
extent of ungulate introductions globally and at a finer resolution in South Africa. It
investigates the pathways, drivers and impacts of ungulate introductions and it also
investigates the use of surrogates for genetic distinctiveness for advising the
translocation of indigenous ungulates. The study finds that ungulate translocations
have been extensive and have lead to the homogenization of ungulate assemblages in
countries globally and at a quarter-degree grid-cell resolution in South Africa. Zoos
were identified as a potential introduction pathway for extraregional ungulates
globally and in South Africa extraregional introductions have made ungulate
assemblages more different; whereas large numbers of extralimital introductions have
made ungulate assemblages more similar. The homogenization of ungulate species in
South Africa has increased with time, due to increased numbers of translocations,
particularly of extralimital species. In South Africa translocations have most recently
been made to high-income areas with high human population density and high
livestock density; whereas in the 1960s ungulates were introduced to areas species poor for indigenous ungulates and marginal for livestock. In South Africa, long
distance translocations of indigenous species extralimitally has resulted in extensive
range expansions of a magnitude greater than predicted range changes as a result of
predicted climate change. When the use of surrogates of genetic distinctiveness for
advising translocations was investigated for Africa, the East African rift valley was
found to be important in delineating genetic distinctiveness and translocations across
this feature should be prevented. Major rivers in Africa also showed potential for
delineating genetic distinctiveness in ungulates, but relevant phylogeographic data are
needed to confirm this. Sufficient evidence for the impacts of non-indigenous
ungulates on biodiversity both in South Africa and globally is lacking despite
substantial concern for their impacts. It is suggested that to demonstrate the impacts of
non-indigenous ungulates exclosure and enclosure experiments should be used and population declines in indigenous species should be shown. / AFRIKAANSE OPSOMMING: Verskuiwing van plante en diere wêreldwyd lei tot groot kommer in gevolge die
bewaring van biodiversiteit. Verskuiwings vind op drie skale plaas, naamlik, die
verskuiwing van inheemse spesies binne hulle natuurlike verspreidingsgebied, die
verskuiwing van spesies buite hul natuurlike verspreidingsgebied maar binne
landsgrense (d.w.s. buite limiet verskuiwings), en die verskuiwing van spesies buite
hul natuurlike verspreidingsgebied en buite landsgrense (d.w.s. buite grondgebied
verskuiwings). Grootskaalse verskuiwing van hoefdiere vind op al drie skale plaas.
Verskuiwing op elk van die skale sal na verwagting biodiversiteit verskillend
beïnvloed. Hoefdiere word ook vir bewaringsdoeleindes verskuif, bv. die
herbevolking van ‘n gebied waar die spesies uitgesterf het, asook om genetiese
probleme wat gepaardgaan met klein bevolkingsgroottes te vermy. Hoefdiere word
ook verskuif vir ekonomiese- en ontspannings redes, o.a. vir sportjag, en sluit
verskuiwings op al drie skale in. Kommer oor verskuiwings binne ‘n spesies se
verspreidingsgebied rus hoofsaaklik op die verlies van genetiese diversiteit a.g.v. die
vermenging van vorig genetiese eiensoortige bevolkings, terwyl op die ander twee
skale kommer hoofsaaklik gebaseer is op die impakte van kompetisie, interteling,
predasie, herbivoor effek, en die verspreiding van parasiete op inheemse
biodiversiteit. Hierdie proefskrif ondersoek die omvang van hoefdier verskuiwings
globaal asook in Suid Afrika. Die verskuiwingsweë, oorsake en impakte van
verskuiwings word hier ondersoek, asook die maatstawwe van genetiese
eiensoortigheid om advies oor verskuiwings te verskaf. Die bevindings toon op
ekstensiewe verskuiwing van hoefdiere wat eenvormigheid van hoefdier
spesiesamestellings wêreldwyd bevorder het, sowel as op ‘n kwartgraad skaal in Suid
Afrika. Dieretuine is geïdentifiseer as ‘n potensiële bron van buite grondgebied
verskuiwings. In Suid Afrika het buite grondgebied verskuiwings hoefdier
spesiesamestellings minder eenvormig gemaak, terwyl buite limiet verskuiwings
hoefdier samestellings binne Suid Afrika meer eenvormig gemaak het.
Eenvormigheid in hoefdier spesiesamestellings het met tyd in Suid Afrika toegeneem
as gevolg van ‘n toename in veral buite limiet verskuiwings. In Suid Afrika is
verskuiwings mees onlangs na hoë-inkomste gebiede met hoë menslike bevolkingsen
veëdigthede gemaak. In die sestiger jare is hoefdiere egter verskuif na gebiede waar min inheemse hoefdiere voorgekom het en wat marginaal was vir veëboerdery.
In Suid Afrika het langafstand buite limiet verskuiwings versoorsaak dat die
verspreidingsgebiede van sekere hoefdier spesies groter is as wat die geval sal wees
met voorspelde klimaatsveranderinge. Waneer surogaat inligting gebruik word om
genetiese verskille tussen bevolkings te identifiseer om verskuiwings te adviseer,
word die Oos Afrika Rift vallei geïdentifiseer as ‘n belangrike breuk tussen
bevolkings. Verskuiwings oor die vallei moet verkieslik nie plaasvind nie. Groot
riviere in Afrika speel ‘n soortgelyke rol, maar verdere genetiese inligting is nodig om
dit te bevestig. Alhoewel kommer oor die impak van verskuiwings groot en teoreties
verdedigbaar is, bestaan daar te min konkrete bewyse vir die impakte in Suid Afrika.
Daar word voorgestel dat manipuleringseksperimente uitgevoer moet word om
impakte te demonstreer, en dat aandag veral gegee moet word aan die demonstrasie van impakte op inheemse spesies.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/4504 |
| Date | 12 1900 |
| Creators | Spear, Dian |
| Contributors | Chown, Steven L., Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Rights | Stellenbosch University |
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