coaltech upper olifants river catchment wetland inventory ...

3.6.9.3 Fauna
A number of alien fish and invertebrate species occur in the wetlands of the UORC. These
species can have a large impact on the indigenous fauna due to competition and pressure
from natural enemies. Trout fishing is a mayor recreational activity in the area and trout are
introduced to trout dams on a continuous basis. The trout often have a negative impact on
the native fish populations, due to competition for resources. The introduction of trout into
rivers where they are absent at present is prohibited (Heath and Claassen 1999, Palmer et al
2002).
3.7 Indicators of wetland health
3.7.1 National River Health Programme
Although rivers are not included as wetlands the health of the river system can reflect the
health of the wetlands in the area. Healthy wetlands, especially healthy riparian wetlands,
have a positive impact on the river health and degraded wetlands often have a negative
impact on the river health.
The National River Health Programme is a programme that assesses the health of a river
system. The health of the river systems are published in reports and are available to the
public (CSIR 2001, http://www.csir.co.za/rhp/index.html). An assessment of the Crocodile,
Sabie-Sand and Olifants River Systems has been conducted as part of this programme.
The UORC is divided into ecoregions, representing distinct units within the catchment. The
ecoregions of the Olifants River catchment relevant to this project are 2.08, 2.09, 7.02, 7.03,
7.04 and 7.05 (Figure 4). Ecoregions 7.02, 7.03 and 7.04 are located in the grasslands of the
escarpment plateau, with some rolling rocky areas interspersed. The Wilge,
Bronkhorstspruit, Klein Olifants and Olifants Rivers originate in these ecoregions. Ecoregions
2.08 and 2.09 are located on the Highveld Plateau and descend the Drakensberg
Escarpment. The confluences of the Olifants and the Klein Olifants Rivers, as well as the
confluence between the Olifants River and the Wilge River are included in these ecoregions
(CSIR 2001).
Tools used to assess the health of the rivers are:
o South African Scoring System (SASS) 5;
Wetland Database for UORC - 54 -