The Swartkops estuary is located on the outskirts of Port Elizabeth, 15 km north of the harbour. The catchment of this river lies in the Groot Winterhoek mountains west of Uitenhage. The lower river receives water primarily from the Swartkops and Elands rivers, which flow parallel to each other, in relatively steep narrow valleys, and have their confluence shortly after entering the flood-plain. The estuary is tidal for c.16 km upstream, the upper reaches are narrow (c.90 m wide), channel-like, and twist their way through steep banks of muddy sand. In the upper estuary there is a small, sandy intertidal area. The estuary widens slightly and becomes less convoluted between Bar None saltpans and Brickfields in the middle reaches. Below Brickfields, the steep banks flatten and the estuary broadens considerably (c.350 m wide) into open mudflats.The permanently open mouth is covered with eelgrass Zostera beds, which disappeared in 1983 resulting in the formation of extensive intertidal mudflats. The Zostera has since returned and the mudflat area has receded. Redhouse saltpan is situated on the north bank of the Swartkops flood-plain, within the Swartkops Valley Nature Reserve. Chatty saltpans occur south of the Swartkops–Redhouse railway-line near Brickfields. Three islands occur at Redhouse saltpan. The primary plants in the saltpans are the macrophytes Ruppia and Enteromorpha. The terrestrial vegetation surrounding the estuary consists of coastal dune herbland, flood-plain scrubland, grassland and thicket.
See Box for key species. This site holds, on average, 14,500 birds each year, and occasionally it passes the 20,000-bird threshold. Redhouse saltpan and the Swartkops estuary each regularly hold more than 4,000 birds a year. On the estuary, up to 3,300 of these are Palearctic migrants, present mainly during the summer months. The estuary and the saltpans provide distinctly different habitats for the 70 waterbird species that regularly occur there. The intertidal mudflats near the mouth of the estuary support the greatest density of birds, including notable numbers of Haematopus moquini, Pluvialis squatarola, Numenius phaeopus and Tringa cinerea. Thirteen species have been recorded breeding at Redhouse saltpan. Two islands at Redhouse saltpan host the second largest coastal breeding colony of Phalacrocorax carbo in southern Africa. Larus dominicanus also breed in large numbers and the pan regularly supports over 430 nests. Redhouse saltpan also holds the second largest breeding colony of Sterna caspia in South Africa, including 20% of the country’s breeding birds in some years.
Non-bird biodiversity: The reptiles Bradypodion ventrale and Scelotes anguineus, two Algoa Bay endemics, are resident.
Pressure/threats to key biodiversity
The Swartkops estuary basin is administered by the Port Elizabeth City Council. Future water demands in and around this growing urban centre may result in the establishment of more impoundments, which will substantially reduce flow and potentially disrupt the ecological functioning of the estuary. A number of state and local bodies are concerned with the estuary and its management and conservation. The Swartkops Trust, in particular, has played an important role in planning and controlling the estuary and environs. Being located in a major urban centre, the adjacent land is used for a variety of purposes, including residential townships, industry and clay mining.It is essential that encroachment by development be prohibited, particularly between the railway-bridge and Redhouse. Redhouse saltpan (owned by the local authority) is regarded as the most important area for breeding seabirds on the Eastern Cape mainland, and it has now been incorporated into the Swartkops Valley Nature Reserve. Redhouse saltpan is still operated as a commercial venture, ensuring that adequate funds and manpower are available for the maintenance of the retaining walls and the continued operation of the waterpump; these commercial functions are vital for waterbird management at the site. The remainder of the site is unprotected; Chatty saltpans are owned by Swartkops Seesout, and the Swartkops estuary is zoned as public open space, which is multifunctional, for the purposes of conservation, recreation and development. Access to the saltpans is restricted to permit holders, but trespassing frequently occurs. Humans steal eggs and cause disturbance, which is probably the main problem facing the breeding birds. The Redhouse saltpan is managed on the basis of a management plan. The Swartkops Valley Nature Reserve, along the northern border of the estuary, conserves this area’s terrestrial vegetation.
BirdLife International (2021) Important Bird Areas factsheet: Swartkops Estuary - Redhouse and Chatty Saltpans. Downloaded from
http://www.birdlife.org on 04/08/2021.