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Invading alien
plants are the single biggest threat to
plant and animal biodiversity through the effects of predation, alteration
of habitat or disruption of ecosystem processes (DWAF,
2002b; UNEP, 2002). Invading alien plants waste 7% of our
water resources, reduce farming productivity, intensify flooding and
fires, cause erosion, degrade river systems, increase the rate of
siltation of dams and estuaries, reduce water quality and can cause
extinction of indigenous plants and animals (DWAF,
2002b). Invading alien plants have become established
in over 10 million hectares of land in South Africa
and if left uncontrolled, the problem could double
within 15 years (DWAF,
2002b).
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| Assessment of
Data |
This indicator reports on the alien invasive
species occurring in Mpumalanga and their distribution. Data for
this indicator is available from the Working for Water Programme.
According to the Working for Water Annual Report 2000/1, two
quarternary catchments
in Mpumalanga Province are more than 10%
invaded by alien plant species and approximately 33 395 hectares
of land has been cleared of alien species
in the province (DWAF,
2001).
Although the Working for Water Programme focuses
on plant alien species, it must be recognised that alien
species from
other taxa also pose a threat to
indigenous biodiversity. This could not be reported on due to
the lack of available data for the distribution
and abundance of these
taxa. |
