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25-470: The Rietvlei Wetland Reserve forms part of the greater 880 hectares (2,200 acres) Table Bay Nature Reserve . Rietvlei is considered as the most important area for waterbirds in the region and is recognized as an Important Bird Area by BirdLife International . Official recognition of its importance to biodiversity by the South African government was first afforded in 1984, when it was established as

50-406: A 99-year lease for the purposes of nature conservation. Fauna and flora in the reserve include the following: Phoenicopterus minor The lesser flamingo ( Phoeniconaias minor ) is a species of flamingo occurring in sub-Saharan Africa and western India . Birds are occasionally reported from further north, but these are generally considered vagrants . The lesser flamingo

75-529: A Nature Area. This was followed by its declaration as a Protected Natural Environment in 1989, and the establishment of the Rietvlei Wetland Reserve in 1993. The first formal management plan for the reserve was developed in 1994, and this has served to guide management activities to the present. The most obvious and dramatic human-induced modification at Rietvlei was the dredging of the entire north-west section between 1974 and 1976. Seawater

100-605: A range of environmental education programmes and utilises the two bird hides and the short footpath for field excursions. The Milnerton Aquatic Club leases an area of land inside the nature reserve from where they promote windsurf, sail, power- and radio-controlled boating. The Southern African Foundation for the Conservation of Coastal Birds ( SANCCOB ) manages a rehabilitation facility at Rietvlei. A range of natural and semi-natural habitats exist in this fluctuating wetland , which floods in winter and dries out in summer when

125-415: A single chalky-white egg on a mound they build of mud. Chicks join creches soon after hatching, sometimes numbering over 100,000 individuals. The creches are marshalled by a few adult birds that lead them by foot to fresh water, a journey that can reach over 20 mi (32 km). Despite being the most common species of flamingo, it is classified as near threatened due to its declining population and

150-607: A variety of species, including marabou storks , vultures , baboons , African fish eagles , jackals , hyenas , foxes , Great white pelicans , Martial Eagle , and big cats . In Africa, where they are most common, the lesser flamingos breed principally on the highly caustic Lake Natron in northern Ngorongoro District in Arusha Region of Tanzania . Their other African breeding sites are at Etosha Pan , Makgadikgadi Pan , and Kamfers Dam . The last confirmed breeding season at Aftout es Saheli in coastal Mauritania

175-489: Is characterized by scant aquatic vegetation, dominated by Ruppia , Potamogeton and Enteromorpha . The reed-marsh is dominated by Phragmites , invaded in places by Typha . The sedge-marsh is dominated by Bolboschoenus and Juncus . The open pans are sparsely covered in macrophytes , consisting mainly of Limosella and Salicornia , and the sedge pans are dominated by Bolboschoenus in summer and Aponogeton and Pauridia in winter. The effects of

200-422: Is suspected for a further 13 species. The high diversity of waterbirds is due to the wide range of wetland habitats present and the proximity of Rietvlei to the ocean , which allows both freshwater and coastal species to exploit the system. Fluctuating water-levels are intrinsic to Rietvlei's biological value. During peak floods, swimming birds of deep, open water abound. Birds of marshy habitats replace these as

225-451: Is the smallest species of flamingo, though it is a tall and large bird by most standards. The species can weigh from 1.2 to 2.7 kg (2.6 to 6.0 lb). The standing height is around 80 to 90 cm (31 to 35 in). The total length (from beak to tail) and wingspan are in the same range of measurements, from 90 to 105 cm (35 to 41 in). Most of the plumage is pinkish white. The clearest difference between this species and

250-778: The Port of Cape Town . It has one major tributary, the Mosselbank, which drains the northern slopes of the Durbanville Hills. Other tributaries include the Swart, Groen, Klein, and Riebeeck, with the Klapmuts being a tributary of the Mosselbank. The total size of the catchment is 1,495 km or 154,347 hectares. A total of 173 species have been recorded at Rietvlei, of which 102 are waterbirds and 76 are present regularly. Breeding has been confirmed for 23 waterbird species and

275-652: The biodiversity management in the built-up area. It is managed by the City of Cape Town 's Environmental Resource Management Department, with offices at Rietvlei. The Table Bay Nature Reserve forms the southernmost buffer area of the Cape West Coast Biosphere Reserve, and links it to the edge of Cape Town's city centre. It also contains a large portion of the critically endangered lowland habitats remaining in Cape Town. The central feature in

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300-476: The greater flamingo , the only other Old World species of flamingo, is the much more extensive black on the bill. Size is less helpful to distinguish the two species, unless they occur together, since the sexes of each species also differ in height. The extinct species Phoeniconaias proeses in the same genus, from the Pliocene of Australia, is thought to have been even smaller. The lesser flamingo may be

325-621: The photosynthetic pigments that give the birds their pink colour. Their deep bill is specially adapted for filtering tiny food items. Other forms of algae taken are Synechocystis minuscula , Synechococcus pevalekii , Synechococcus elongatus , Monoraphidium minutum , Oscillatoria sp. and Lyngbya sp. This species will also feed, to a lesser extent, on small invertebrates: copepods ( Paradiaptomus africanus ), diatoms ( Navicula ) and rotifers ( Brachionus ), as well as microscopic alkaliphilic cyanobacteria ( Arthrospira fusiformis , A. maxima ). Lesser flamingos are prey to

350-552: The wetland . Table Bay Nature Reserve The Table Bay Nature Reserve is an 880-hectare (2,200-acre) nature reserve in Milnerton , Western Cape , South Africa . It consists of several smaller constituent reserves including Rietvlei Wetland Reserve , Diep River Fynbos Corridor , Zoarvlei Wetlands , Milnerton Racecourse Nature Reserve , and Milnerton Lagoon, as well as surrounding protected areas. These adjacent reserves were amalgamated on 27 June 2012, in order to improve

375-582: The Diep estuary . If the 5 metres (16 ft) contour above mean sea level is used as the estuary delineation, then the Diep estuary entirely encompasses the Rietvlei Wetland Reserve. The Diep River has its origins in the Riebeek Kasteel Mountains north-east of Malmesbury from where it flows for about 65 kilometres (40 mi) south-west towards Cape Town before entering the sea at Milnerton , some 5 kilometres (3.1 mi) north of

400-716: The Table Bay Nature Reserve is the Rietvlei wetland system. The Rietvlei Wetlands and Milnerton Lagoon were proclaimed as a Nature Area on 3 August 1984, in proclamation number 1632 of Provincial Gazette No. 9345. The Nature Reserve is partly owned by the City of Cape Town and the World Wildlife Fund for Nature – South Africa, who own two of the Erven. The City of Cape Town manages these two Erven on

425-497: The estuary mouth closes. These habitats include shallow marine waters, estuarine waters, sand/shingle shores, tidal mudflats, saltmarshes, coastal brackish saline lagoons, rivers , streams and creeks , permanent freshwater lakes and permanent and seasonal freshwater marshes and pools. The Diep River flows through the Rietvlei wetland and the Milnerton Lagoon, which together have generally been considered to comprise

450-575: The low number of breeding sites, some of which are threatened by human activities. The population in the two key East African lakes, Lake Nakuru and Lake Bogoria , have been adversely affected in recent years by suspected heavy metal poisoning , while its primary African breeding area in Lake Natron is currently under threat by a proposed soda ash plant by Tata Chemicals . The only breeding site in South Africa, situated at Kamfers Dam ,

475-404: The margin of the system also pose problems. Vast areas of the mudflats and salt marsh have been smothered by thick mats of non-native grasses, notably Paspalum vaginatum , resulting in habitat loss for waders, the most diverse and abundant community of waterbirds at Rietvlei. Other non-native species, including stands of Acacia saligna , are being cleared from large areas around the margin of

500-405: The most common species of flamingo, with a population that (at its peak) probably numbered up to two million individual birds. This species feeds primarily on Spirulina , algae which grow only in very alkaline lakes . Presence of flamingo groups near water bodies is an indication of sodic alkaline water which is not suitable for irrigation use. Although blue-green in colour, the algae contain

525-636: The nearby Century City Development on Blouvlei, which used to support a large heronry holding 12 breeding species, is cause for considerable concern. Most of these birds used to forage at Rietvlei and would contribute substantially to the large numbers of birds occurring here. The effects on this breeding area will probably result in fewer birds visiting the Rietvlei area. Other threats to the wetland include siltation , which results from erosion , and pollution and eutrophication from fertilizers , pesticides , sewage works , stormwater run-off and livestock manure . Petroleum factories and suburban areas on

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550-531: The site, but not in globally significant numbers. Zooplankton multiply rapidly after winter flooding and disappear in summer as the water dries up. In the estuary there is a range of salinities, resulting in a diverse community of zooplankton . The invertebrate fauna is a vital food source for birds and fish, the most abundant fish in the wetland being Liza richardsonii . Five distinctive wetland plant communities occur: perennial wetland, reed-marsh, sedge-marsh, open pans and sedge pans. The perennial wetland

575-419: The water recedes, and waders exploiting shallow mudflats occur in great abundance just prior to the wetland drying up. Rietvlei has been ranked as the sixth most important coastal wetland in South Africa for waterbirds , and it supports an average of 5,550 birds in summer; during good years, however, numbers are boosted above 15,000. Phoenicopterus minor , a species of global conservation concern, occurs at

600-641: Was in 1965. Breeding occurred at Lake Magadi in Kenya in 1962 when Lake Natron was unsuitable due to flooding. In the early 20th century, breeding was also observed at Lake Nakuru . The species also breeds in southwestern and southern Asia. In 1974, they bred at the Rann of Kutch , but since then, only at the Zinzuwadia and Purabcheria salt pans in northwestern India. Some movement of individuals occurs between Africa and India. Like all flamingos, they lay

625-595: Was pumped into the pans to facilitate the operation and a vast area was dredged to a depth of 9 metres (30 ft). The ecological consequences were profound and irreversible. A sizable portion of Rietvlei's shallow ephemeral pans was changed into a permanent deep-water lake, which resulted in a total change in ecological character for this portion of the system. Rietvlei Wetland Reserve offers various user activities, including several types of water sport recreation, bird watching, picnic, fishing and outdoor environmental education opportunities. The Rietvlei Education Centre hosts

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