Spitskop Dam lies 33 km south-west of Jan Kempdorp and 27 km west of Warrenton. This is one of the largest wetlands in the semi-arid Northern Cape region. It holds water permanently and is a vital habitat when many ephemeral and temporary wetlands in the region have dried up. The dam's major inflow is from the Harts River.
This IBA falls within the Savanna Biome and Eastern Kalahari Bushveld Bioregion. There are two main vegetation types, and the ecosystem status for both the Schmidsdrif Thornveld and Kimberley Thornveld is Least Threatened. The thornveld is dominated by umbrella thorn Vachellia (formerly Acacia) tortilis and black thorn V. mellifera, with camel thorn V. erioloba, sweet thorn V. karroo and shepherd's tree Boscia albitrunca present. The shrub layer is moderately developed in places and includes camphor bush Tarchonanthus camphoratus and raisin bush Grewia flava. The grass layer is sparse. The water's edge where the Harts River flows into the dam is dominated by common reed Phragmites australis, which also occurs in patches along the dam shoreline.
Approximately 30% of the terrestrial area of this IBA is in a natural state and 70% has been degraded or transformed. As is the case with many other wetlands in South Africa, Spitskop Dam has been severely affected by human activity. It is a highly disturbed impoundment as a result of years of continuous degradation due to excessive livestock grazing and pollution from agricultural pesticides and fertilisers.
Situated in a region where rainfall is unpredictable, this large, permanent waterbody is of major importance during drier periods when other wetlands dry up. In this dynamic aquatic ecosystem, the species and numbers of waterbirds change with fluctuating water quality and water levels. The ecosystem regularly supports more than 10 000 birds, and on occasion over 20 000 individuals. The dam sustains important species such as Pink-backed Pelican Pelecanus rufescens, Caspian Tern Sterna caspia, Greater Flamingo Phoenicopterus roseus and Lesser Flamingo Phoeniconaias minor. Other species, such as Great Crested Grebe Podiceps cristatus, White-breasted Cormorant Phalacrocorax lucidus, African Darter Anhinga rufa, African Spoonbill Platalea alba, South African Shelduck Tadorna cana, Red-knobbed Coot Fulica cristata and Pied Avocet Recurvirostra avosetta, occur here in significant numbers.
The total number of species recorded to date during both SABAP1 and SABAP2 is 249, and 221 species have been recorded during SABAP2. At the time the IBA was assessed, all six of its pentads had been atlased but few cards had been submitted.
The CWACs for 1991 to 2006 (MD Anderson CWAC data) show that this IBA is important for waterbirds in the Northern Cape. There have been globally significant numbers of Great Crested Grebe, Little Grebe Tachybaptus ruficollis and African Darter (breeding) in winter, and of African Spoonbill and South African Shelduck in summer. The IBA also supports significant numbers of Cape Shoveler Anas smithii and White-winged Tern Chlidonias leucopterus in summer and Goliath Heron Ardea goliath all year.
The highest number of waterbirds counted was 26 377 in February 2003 (MD Anderson CWAC data). Red-knobbed Coot was the most abundant species, followed by South African Shelduck and Little Stint Calidris minuta. The most recent count (August 2010) had a total of 15 156 waterbirds (E Herrmann CWAC data).
The species richness of waterbirds has remained relatively constant at an average of 50 species. A maximum of 63 waterbird species was recorded in 2006. There is some evidence of a temporal increase in the number of waterbirds (MD Anderson, E Herrmann CWAC data) between 1991 and 2010.
Low numbers of Secretarybird Sagittarius serpentarius, African Marsh Harrier Circus ranivorus, Lanner Falcon Falco biarmicus, Western Osprey Pandion haliaetus and Amur Falcon F. amurensis frequent the dam. Four African Fish Eagles Haliaeetus vocifer are resident. Marabou Stork Leptoptilos crumeniferus and Abdim's Stork Ciconia abdimii are occasionally present in low numbers.
Globally threatened species are Lesser Flamingo (980 to 5 800; this and following figures from MD Anderson, E Herrmann CWAC data) and Chestnut-banded Plover Charadrius pallidus. Regionally threatened species are Greater Flamingo (100 to 1 000), Caspian Tern (four to 230), Pink-backed Pelican (ten to 50) and Yellow-billed Stork Mycteria ibis. Biome-restricted species are Burchell's Sandgrouse Pterocles burchelli, Kalahari Scrub Robin Erythropygia paena and Barred Wren-Warbler Calamonastes fasciolatus. Congregatory species are Great Crested Grebe, Little Grebe, South African Shelduck, Pied Avocet, African Darter, African Spoonbill, Cape Shoveler, Whiskered Tern Chlidonias hybrida, White-winged Tern and Red-knobbed Coot.
One of the most important threats is the poor water quality of Spitskop Dam, fed by the Harts River. The water quality of the Harts River deteriorates downstream of Taung Dam (which lies upstream of Spitskop Dam), due to irrigation return flows with increasing concentrations of sodium, magnesium, chloride, sulphate and nutrients. At times Spitskop Dam is eutrophic, with blue-green algal blooms. Any further addition of nutrients due to irrigation expansion could move the dam towards a hypertrophic status. Releases from Spitskop Dam could impact on the quality of the Vaal River and could exacerbate the blue-green algae outbreaks in the lower Orange River. Herbicides and pesticides used for crop farming upstream are also considered a threat but have not been quantified.
The water yield of Spitskop Dam is largely dependent on the return flows generated from the Vaalharts Irrigation Scheme. Any increase in activities that have an effect on the water use and return flows will have a major impact on the yield of Spitskop Dam. The Taung Irrigation Scheme is being expanded. Should it be expanded above the recommended limit to maintain water yields in the dams, Spitskop Dam will function as an evaporation lake with only EWR releases being made downstream.
Other important threats in this IBA include the hunting or poaching of waterbirds, fishing activities and livestock grazing and trampling. The dam edges are threatened by the common reed, the dominance of which reduces the foraging area for flamingos and waders that prefer open shoreline. A few invasive alien plants, including mesquite Prosopis species, are present and not controlled.
Predictions on climate change for South Africa state that temperatures will increase and rainfall decrease sharply in arid areas. In the central regions of South Africa, climate change scenarios predict summer rainfall to be slightly higher by 2050, and it may also become more variable. Droughts are predicted to become more severe due to climate change. Responses to drought may be species-specific. Bush thickening and/or encroachment is expected to increase with increased atmospheric carbon levels.
Renewable energy developments are a new threat in the region. At this stage there are no solar or wind energy facilities approved or proposed for development within this IBA, and only one nearby. Some of the trigger species in this IBA, such as Lesser Flamingo, are predicted to be moderately susceptible to solar energy facilities.
Spitskop Dam has no formal protected status and ownership falls under three different bodies: the DWA, private farmland and undeclared State land. DWA manages the dam for water consumption and recreation. In the rural northern sector, the land is intensively grazed by livestock, including cattle, goats and donkeys.
Regular bi-annual CWACs were undertaken to monitor waterbird numbers from 1991 to 2006 by MD Anderson while he was employed as ornithologist at the Northern Cape DENC. Subsequently, a CWAC was completed in August 2010 by E Herrmann, a zoologist at DENC. These counts have been discontinued.
No other conservation actions have been implemented. Formal protection, a proper management plan and monitoring are needed.
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