coaltech upper olifants river catchment wetland inventory ...

One of the reptile species, the Striped Harlequin Snake (Homoroselaps dorsalis) is included
in the Gauteng Department of Agriculture, Conservation and Environment (GDACE) species
list of species of concern. The species prefers grassland as its habitat and is therefore not
wetland dependant (Branch 1998). The wetlands may, however serve as refugia for the
species, especially the drier/temporary wetlands. A number of additional reptile species are
protected under the Nature Conservation Ordinances and are included as species of
concern.
3.3.4 Amphibians
A wide variety of frog species utilise wetlands in the UORC. Of the 23 frog species that have
been observed in the UORC and the five species from adjacent areas, 26 are wetland
dependant. Pyxicephalus adspersus (Giant Bullfrog), a Near Threatened species is the only
species of concern observed in the UORC (Bryan Maritz pers com 2005). The Giant Bullfrog
occurs in a variety of vegetation types including the Grassland, Savanna, Nama Karoo and
Thicket biomes. They breed in seasonal, grassy, shallow pans, but can also utilise non-
permanent vleis, as well as shallow water next to waterholes and dams. These vleis and
dams occur in flat open areas. They prefer sandy substrates, but sometimes utilises clay
soils (Minter et al 2004).
3.3.5 Invertebrates
Existing data studied by Palmer et al (2002) indicated that the aquatic invertebrates found in
the UORC consist mostly of common, widespread taxa. The abundance and productivity of
these taxa are important to maintain higher trophic levels, most notably birds. The local
variation in the species composition is also high, probably due to local variation in habitat.
Although most insect species have good dispersal abilities, their ability to disperse into
disturbed areas is dependant on the availability of natural refugia. Most of the crustacea and
snail species are adapted to temporary dry conditions, whereas some other species depend
on areas that are permanently wet. Dams and weirs therefore favour species dependant on
permanent wet conditions and lowers the diversity, and species numbers adapted to
temporary dry conditions. It is therefore necessary to maintain a mosaic of temporary,
seasonal and permanently wet systems in order to support the wide variety of aquatic
invertebrates potentially utilising the wetlands in the catchment (Palmer et al 2002, CSIR
2001).
Wetland Database for UORC - 26 -