Current view: Text account
Site description (2001 baseline):
Site location and context
Umvoti vlei lies 11 km due south of Greytown. It forms the headwaters of the Umvoti river. The terrain is almost flat. The wetland owes its existence to a sill of tough sandstone that has retarded downcutting of the Umvoti river. There is some open water at the lower end of the vlei, where clay soils impede drainage. However, the major part of the site, where the soils are alluvial, is a dense, tall, permanently flooded reedbed
Phragmites. Sedge meadows with
Cyperus,
Carex,
Leersia and
Juncus form narrow fringes in places.
See Box for key species. The wetland areas are good for
Grus carunculatus and
Balearica regulorum, which winter here in large numbers. The surrounding grassland supports several species of conservation concern, including
Geronticus calvus,
Grus paradisea,
Neotis denhami and
Circus maurus. The site is suspected to hold several pairs of
Botaurus stellaris. The
Carex beds have good potential for
Sarothrura ayresi.
Non-bird biodiversity: None known to BirdLife International.
Pressure/threats to key biodiversity
Of the greater Umvoti vlei (2,800 ha), only about a quarter (675 ha) is permanent wetland and less than half of this falls within a proclaimed reserve. So the fortunes of the reserve, in particular its water-levels and fire regime, are linked to those of the whole vlei. The vlei has a long history of mismanagement. The first drains were cut in 1918. In 1949, the Lion Match Company, one of the major land-owners, excavated a large canal that lowered the water-table by 30–90 cm. Only 32 ha of land suitable for poplar planting were so created. Public outcry prompted the Ministry of Agriculture to expropriate the affected land in 1950. Attempts to build barriers across the canals were generally unsuccessful, and uncoordinated fires were especially damaging. In dry years the peaty soils catch fire, making fire-break creation almost impossible.
Restoration of the damaged area was proving so difficult that in 1975 the expropriated lot was given to the KwaZulu-Natal Nature Conservation Service (formerly the Natal Parks Board) and proclaimed a Nature Reserve. Since then all the artificial drains have been blocked with clay-filled bags, raising the water-table by up to 30 cm. In an attempt to improve habitat diversity, some of the
Phragmites has been removed in order to create more open water (recolonization is prevented by fire and a higher water-table). The main threats now to Umvoti vlei are land-use practices within the catchment. Both forestry and crop farming, which require much irrigation, lessen the flow of water into the vlei. The vlei has a gradient of 0.15%, the ideal for maximizing silt entrapment and flood reduction, and its functioning is considered essential for the well-being of the whole Umvoti river system.
Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Umvoti Vlei (South Africa). Downloaded from
https://datazone.birdlife.org/site/factsheet/umvoti-vlei-iba-south-africa on 22/11/2024.
