The use of archaeological and ethnographical information to supplement the historical record of the distribution of large mammalian herbivores in South Africa
Year: 2006
Type: article
Abstract: Introduction The introduction of animal taxa to areas where they do not naturally occur has the potential to damage severely the native fauna and flora. Introductions, both accidental and intentional, to Australia, New Zealand, Marion Island and other oceanic islands provide spectacular examples of this. Non-native mammalian herbivores often become invasive in the absence of their natural predators and their impact on vegetation, which may include alterations to plant species composition, structure and diversity, is exaggerated, especially if the vegetation has evolved in the absence of similar herbivores. This influence is not limited to the direct consequence for the vegetation and there may be a cascade effect on ecosystem functioning through, for example, a decline in the amount of available forage for indigenous herbivores, a reduction in the breeding efficiency of birds that rely on the vegetation, and a negative effect on carbon storage by transforming stands of dense vegetative cover to open savannalike systems. Nor are these outcomes restricted to non-native herbivores; the re-introduction of a species, such as the elephant (Loxodonta africana), to areas from which it has been absent for many years may have similar consequences. Additional problems associated with the uncontrolled movement of large mammals include the transmission of disease, such as brucellosis in the United States, and a threat to the genetic integrity of a species through hybridization. It is thus clear that deliberate introductions of herbivores to areas where they do not naturally occur may not be sound conservation practice. In terms of the IUCN position statement on the translocation of living organisms, however, the introduction of an alien species may be considered if it has clear and well-defined benefits for man or natural communities. Furthermore, the condition of the habitat should be considered and, while no introductions should be allowed in pristine or natural habitats, this may be relaxed for man-made habitats and those modified by man. The recent growth in private wildlife ranching and ecotourism, especially in semi-arid areas that are considered marginal for traditional agricultural practices, has resulted in an increase in the movement of large mammals and, in some cases, introductions to regions outside their historical distribution. Significantly, in most cases these new ventures are pursued on old farmlands that cannot be regarded as pristine, natural habitats. The National Environmental Management: Biodiversity Act (Act No. 10 of 2004), prohibits the introduction and spread of an alien species to an ecosystem or habitat where it does not naturally occur. The act defines an alien species as one that is not indigenous or is translocated to a place outside of its natural range. The act furthermore provides the legislative framework with which to control the translocation of large mammals. In an attempt to implement the act, a draft policy on the national norms and standards for the translocation of mammalian herbivores has been promulgated. Both the Biodiversity Act and the draft policy document, however, make reference to recent historical distributions, and use these as a key criterion to control herbivore translocations. The document goes so far as to suggest giving private landowners incentives for stocking indigenous herbivores, proposing that ‘...those [properties] supporting historically appropriate taxa under natural conditions [will enjoy] the highest status’. While this may appear to be sensible, the questions that we address here are the levels of certainty that we can ascribe to the historical distribution of large mammals in southern Africa, and the length of the history.
Source: South African Journal of Science
Authors: R. T. F. Bernard, Daniel M. Parker
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: diamond
OpenAlex ID: W2324503636