Approximately 80 km north of Richards Bay lies iSimangaliso Wetland Park and World Heritage Site. The park is located on the Mozambique coastal plain at an altitude of between 0 and 480 m a.s.l. at the foothills of the Lebombo Mountains. It is bounded by the uMfolozi River to the south, Mozambique to the north, the Lebombo Mountains to the west and the Indian Ocean to the east. A broad diversity of habitats and features make up this extensive coastal park. The wetlands, pans, lagoons and estuaries play an internationally significant role for waterbird species that are nomadic in the area when conditions change, and are a staging site for migrants along the East Coast Flyway.
The basin of St Lucia Lake was cut during the Quaternary when sea levels were lower. It is surrounded by three distinct areas: the Eastern Shores, the Western Shores, and False Bay. Five rivers enter the lake: the Nyalazi, Hluhluwe and Mzinene discharge water into False Bay, their floodplains forming more than 3 000 ha of shallow-water habitat when flooded; the Mkhuze River filters through a massive swamp of papyrus and reeds before flowing into the northern section of Lake St Lucia; and the small Mphathe River flows into The Narrows. The lake system is about 70 km long and, excluding The Narrows, ranges between 3 and 18 km wide for most of its length. It is the largest estuarine system in Africa, with a water surface area that varies between 225 and 417 km². Seasonal and long-term hydrological conditions are variable and include periods of hyper-salinity that result in large changes in the composition and abundance of plant, invertebrate, fish and bird species.
The main habitat types are mangrove-fringed tidal banks, islands, estuarine mudflats, beds of sedges and tall reeds, swamps and grassland. During long-term wet cycles the swamps and grassland become flooded seasonally and surround patches of bush and forest on higher ground. The dry sand forest around False Bay is never flooded.
The marsh and swamp complex that the Mkhuze River passes through before draining into Lake St Lucia in the north is rich in nutrients and characterised by floating vegetation. It contains important habitat types, including large areas of reedbed and marsh with sedges and grass, pans with good fringing and emergent vegetation, swamp forest bordered by sedge beds, and coastal grassland.
The Mkhuze River enters the park in the west, flowing through an impressive gorge in the Lebombo Mountains in the area of the Mkhuze Game Reserve. The Msunduzi River flows from west to east, joining the Mkhuze River at Nsumo Pan. There are two more large pans, kuDiza and Nhlonhlela, in the east near the Mhkuze River, but they are not permanently connected to it. The tropical bush savanna of this area is exceptionally diverse. Floodplain grasslands occur on seasonally inundated flats adjacent to the Mkhuze and Msunduzi rivers. The major pans, particularly Nsumo Pan, are nutrient-rich and characterised by floating vegetation. A fig forest surrounds Nsumo Pan and riverine forest lines the banks of the Mkhuze River.
To the north of the main Mkhuze swamp are the Mozi, Mpempe and Mdlanzi pans, which are long, narrow cut-off lakes with mostly bare shorelines and reedbeds mainly at the northern end. In the Ozabeni area, the soil becomes progressively sandier and grassland dominates. Together the Mkhuze swamp and Ozabeni area contain a diverse mosaic of wetland vegetation and appear to be largely undisturbed.
Kosi Bay is an estuary-linked lake system that has been transformed into circular bays and lagoons containing fresh or brackish water, separated from one another by low beach barriers. The system comprises four roughly circular, interconnected lakes – Makhawulani, Mpungwini, Nhlange and aManzimnyama – a broad channel leading to an estuary that opens to the Indian Ocean, and three extensive areas of swamp. Two principal rivers, Siyadla and Nswamanzi, feed into it. The vegetation includes swamp forest, which is dominated by the giant raffia palm Raphia australis. This is also the only system in South Africa in which five species of mangrove are found. Dune forest grows on coastal sand dunes in a band 1–3 km wide that runs parallel to the seashore. Species richness in this forest is high.
The climate is subtropical, with maximum temperatures varying between 23 °C and 30 °C. Rainfall averages between 670 and 1 100 mm p.a. and falls mostly in summer (October–March).
iSimangaliso Wetland Park supports more than 500 bird species and is one of the most important breeding areas for waterbirds in South Africa, with at least 48 species having bred here. Due to the variability of the St Lucia system, the lakes may hold very important numbers of a species in some years and almost insignificant numbers in others. The numbers and diversity of waterbirds vary considerably in response to environmental changes. Not only are waterbirds largely absent during periods of high salinity or elevated water levels, but many species are migratory or nomadic, occurring only in defined seasons.
The lakes, pans and wetlands around Lake St Lucia hold large numbers of Pink-backed Pelican Pelecanus rufescens, Great White Pelican P. onocrotalus, Yellow-billed Stork Mycteria ibis, African Spoonbill Platalea alba, Whiskered Tern Chlidonias hybrida, African Fish Eagle Haliaeetus vocifer, Grey-headed Gull Chroicocephalus cirrocephalus, Cape Shoveler Anas smithii, Yellow-billed Duck A. undulata, White-faced Whistling Duck Dendrocygna viduata, African Jacana Actophilornis africanus, Pied Avocet Recurvirostra avosetta and Lesser Flamingo Phoeniconaias minor. Substantial numbers of Palearctic migrant waders occur in summer, with Common Ringed Plover Charadrius hiaticula, Curlew Sandpiper Calidris ferruginea and Little Stint C. minuta making up the majority of the visitors.
Greater Flamingo Phoenicopterus roseus bred here in 1972, when some 30 000 birds and 6 000 nests were recorded during favourable shallow-water, high-salinity conditions. iSimangaliso also holds breeding Goliath Heron Ardea goliath and the only breeding population of Saddle-billed Stork Ephippiorhynchus senegalensis in KwaZulu-Natal. The lake can support more than 80% of South Africa's breeding population of Caspian Tern Sterna caspia and a large proportion of the country's Woolly-necked Stork Ciconia episcopus and Collared Pratincole Glareola pratincola populations. A number of other important breeding colonies are found here, including the only known colony of Great White Pelicans in south-eastern Africa at False Bay; one of only three Pink-backed Pelican colonies in South Africa at Nsumo Pan; and one of only two South African colonies of Yellow-billed Storks, also at Nsumo Pan.
Wetland-dependent species that occur include Black Heron Egretta ardesiaca, African Openbill Anastomus lamelligerus, African Pygmy Goose Nettapus auritus, Long-toed Lapwing Vanellus crassirostris, African Grass Owl Tyto capensis and Marsh Owl Asio capensis. Occasionally small numbers of Lesser Jacana Microparra capensis, Lesser Moorhen Gallinula angulata and Allen's Gallinule Porphyrio alleni are present. Swampy backwaters with overhanging vegetation are home to White-backed Night Heron Gorsachius leuconotus, African Finfoot Podica senegalensis and Pel's Fishing Owl Scotopelia peli.
The open floodplain and flooded grassland areas with dunes hold Short-tailed Pipit Anthus brachyurus, Black-rumped Buttonquail Turnix nanus, Swamp Nightjar Caprimulgus natalensis, Black Coucal Centropus grillii and Rosy-throated Longclaw Macronyx ameliae, and African Marsh Harrier Circus ranivorus may be found hunting over flooded grassland or marshy or swampy habitat. Marginal vegetation around the swamps supports Southern Brown-throated Weaver Ploceus xanthopterus.
Three restricted-range species of the South East African Coast EBA are common in sand forest thickets: Rudd's Apalis Apalis ruddi, Neergaard's Sunbird Cinnyris neergaardi and Pink-throated Twinspot Hypargos margaritatus. The endemic nominate subspecies of African Broadbill Smithornis capensis capensis is also found here. Coastal forests hold Southern Banded Snake Eagle Circaetus fasciolatus, and in winter small numbers of the globally threatened Spotted Ground Thrush Zoothera guttata occur. Biome-restricted species associated with coastal forests include Brown Scrub Robin Erythropygia signata, Chorister Robin-Chat Cossypha dichroa, Woodwards' Batis Batis fratrum, Black-bellied Starling Notopholia corrusca and Grey Sunbird Cyanomitra veroxii, while the woodlands hold White-throated Robin-Chat Cossypha humeralis and Gorgeous Bush-Shrike Chlorophoneus viridis. Large riverine trees are suitable for Bat Hawk Macheiramphus alcinus. The ilala palm specialist, Lemon-breasted Canary Crithagra citrinipectus, is also present in patches of palm savanna.
The extensive forest of raffia palms at Kosi Bay supports the largest population of breeding Palm-nut Vulture Gypohierax angolensis in South Africa, although this site is relatively peripheral and insignificant to the Palm-nut Vulture's more cosmopolitan Afro-tropical range. Mangroves are home to Mangrove Kingfisher Halcyon senegaloides.
Savanna habitat adjacent to the Lebombo Mountains is important for tree-nesting raptors such as Martial Eagle Polemaetus bellicosus, Bateleur Terathopius ecaudatus and Tawny Eagle Aquila rapax, as well as vultures such as White-backed Vulture Gyps africanus, Lappet-faced Vulture Torgos tracheliotos and White-headed Vulture Aegypius occipitalis.
Globally threatened species are Spotted Ground Thrush, Denham's Bustard Neotis denhami, Lesser Flamingo, White-backed Vulture (6–8 breeding pairs and 18–24 individuals), Bateleur (two breeding pairs and up to six individuals), Secretarybird Sagittarius serpentarius, Crowned Eagle Stephanoaetus coronatus and Southern Banded Snake Eagle. Regionally threatened species are Pink-backed Pelican (250–300 breeding pairs and 600–900 individuals), Saddle-billed Stork, Tawny Eagle (2–3 breeding pairs and up to ten individuals), African Marsh Harrier, Black-rumped Buttonquail, African Finfoot, Caspian Tern (170 breeding pairs and up to 850 individuals), African Grass Owl, Pel's Fishing Owl, Swamp Nightjar, Mangrove Kingfisher, Short-tailed Pipit, Great White Pelican (2 000 breeding pairs and 5 000 mature individuals, with up to 7 000 counted), African Pygmy Goose, Lanner Falcon Falco biarmicus, Lesser Jacana, Half-collared Kingfisher Alcedo semitorquata, African Broadbill, Rosy-throated Longclaw and Lemon-breasted Canary.
Restricted-range and biome-restricted species commonly encountered in suitable habitat are Southern Banded Snake Eagle, Brown-headed Parrot Poicephalus cryptoxanthus, Mangrove Kingfisher, Livingstone's Turaco Tauraco livingstonii, Chorister Robin-Chat, White-throated Robin-Chat, Brown Scrub Robin, Stierling's Wren-Warbler Calamonastes stierlingi, Rudd's Apalis, Woodwards' Batis, Gorgeous Bush-Shrike, Olive Bush-Shrike Chlorophoneus olivaceus, Black-bellied Starling, Neergaard's Sunbird, White-bellied Sunbird Cinnyris talatala, Grey Sunbird, Pink-throated Twinspot and Lemon-breasted Canary.
Species that surpass the 1% congregational threshold are Caspian Tern (c. 170 breeding pairs and up to 800 individuals have been recorded), African Spoonbill (200–500 breeding pairs and up to 1 340 individuals), Greater Flamingo (c. 3 000 individuals on average, but up to 18 000 individuals have been recorded), Great White Pelican and Yellow-billed Stork (100–170 breeding pairs and 300–400 individuals). Species that surpass the 0.5% congregational threshold are Whiskered Tern, Goliath Heron (c. 55 on average, but up to 140 have been counted), Great Egret Egretta alba (c. 108 on average, but up to 663 have been counted), Lesser Flamingo (c. 1 300 individuals on average, but up to 14 000 have been counted), Curlew Sandpiper (c. 650 on average, but up to 4 100 have been counted) and Little Stint (c. 400 on average, but up to 3 700 have been counted).
As befits a World Heritage Site, iSimangaliso has a wealth of Red Data and endemic species. Red Data plants are Warburgia salutaris, Lumnitzera racemosa and Diospyros rotundifolia. The only known population of the climbing orchid Vanilla roscheri occurs here. Another very localised plant is the forest-edge climber Ceropegia arenaria. Rare trees in the forest are Ficus bubu and Warburgia salutaris. Brachystelma vahrmeijeri is present in the grassland. The Lebombo Mountains support many rare plants, including two cycads, Encephalartos ngoyanus and E. lebomboensis.
Five butterfly species are endemic to the IBA. There are eight known Red Data fish species that occur, including freshwater mullet Myxus capensis and Sibayi goby Silhouettea sibayi. Among the rare lizards present are two local endemics, coastal dwarf burrowing skink Scelotes vestigifer and Setaro's dwarf chameleon Bradypodion setaroi. The endangered gaboon adder Bitis gabonica occurs in the forest leaf litter. iSimangaliso has KwaZulu-Natal's largest population of crocodile Crocodylus niloticus. Of the mammals, hippopotamus Hippopotamus amphibius, aardwolf Proteles cristatus, aardvark Orycteropus afer, pangolin Manis temminckii and suni Neotragus moschatus occur naturally. Black rhinoceros Diceros bicornis has been re-introduced.
Lake St Lucia depends heavily on the input of sufficient fresh water to function and has been subjected to a history of modification and dramatic shifts. Originally the uMfolozi River and Lake St Lucia had a common mouth. When it was thought that silt from the uMfolozi was filling the lake as a result of the canalisation of the river, a separate mouth was created for it in 1959. The mouth was actively maintained until June 2002, when fresh water stopped flowing into it from the uMfolozi River because of drought conditions. This led to a dramatic increase in salinity levels, driven by the low riverine input and high evaporation rate.
The iSimangaliso Authority subsequently raised funding from the GEF to investigate and implement a long-term solution to the hydrological issues facing the Lake St Lucia system. In 2011 iSmangaliso publicised its strategy, based on research and the input of scientists, to let the uMfolozi River and Lake St Lucia re-join in a bid to restore the functioning of the estuarine system.
During 2012 the uMfolozi came within 300 m of the St Lucia mouth. This made the linking of the two systems possible and in March the iSimangaliso Authority and EKZNW used a tracked excavator to establish a beach spillway between the two mouths. The final linkage was made in July of the same year, when the uMfolozi mouth closed. Salinity, lake levels and ecosystem health are carefully monitored. There are indications that the spillway was extremely successful in transferring a large volume of water from the uMfolozi catchment to Lake St Lucia while the mouth was closed; when it was open, a marine linkage to St Lucia was reinstated for the first time in ten years.
Colonial breeding sites of birds are vulnerable to damage by human disturbance. African Skimmer Rynchops flavirostris used to breed on the shallow sandbanks at St Lucia, but disturbance and man-induced changes in their main breeding and feeding areas caused the birds to abandon the site. This resulted in the extinction of this species in South Africa. Today disturbance to breeding colonies is kept to a minimum. In 1983 the Pink-backed Pelican breeding colony at the mouth of the Hluhluwe River in False Bay was deserted. The birds moved to Nsumo Pan in Mhkuze Game Reserve where, for reasons that are not obvious, they still breed today.
The area has a history of utilisation, habitat modification and abuse by humans, and human population pressure is increasing along the western boundary of the park. In many respects the current habitat structure is the result of modification. Sections of riverine forest were cleared in the 1980s. River channels have been diverted and canals dug, resulting in increased river gradients and erosion. In some cases, eroding riverbeds have cut back to pans and drained them. Uncontrolled reed harvesting and the tapping of ilala palms Hyphaene coriacea for sap also contribute to habitat degradation. Access to the park is now restricted, but incursions into it do take place, especially in the context of complex land rights issues. Cattle graze in the park, especially at Ozabeni, and slash-and-burn farming practices have led to the destruction of swamp forest habitat, particularly in the north. The swamp forest in the area is the largest intact example of this habitat in KwaZulu-Natal and is listed as Critically Endangered. Destruction of it outside iSimangaliso is a serious challenge; inside the park, the habitat is closely monitored.
Illegal gill-net fishing is a significant threat and although it is receiving serious attention, it persists in parts of the park at levels that are sometimes high. Traditional fishing practices that have been used for centuries are permitted to continue at Kosi Bay. There are concerns, however, that fishing may move beyond the subsistence level, leading to declines in fish species in the lake.
Afforestation and the increased use of fertilisers in the catchment area pose a threat to the system by reducing water run-off and resulting in the eutrophication of the water that does reach the lake. Exotic plants thrive and need to be controlled before they overwhelm the local indigenous vegetation.
It is estimated that as much as a third of the vulture population at Mkhuze Game Reserve has been lost in recent times. The previous IBA directory (Barnes 1998) quoted c. 200 breeding pairs, which may have been optimistic. Now, with an estimated 6–8 pairs remaining (based on the latest aerial counts undertaken by EKZNW), the population is under severe threat. The decline is attributed to the poisoning of birds for use in 'muti' markets. The most recent incident took place in late 2013, when 40 White-backed Vultures were found with their heads removed. It is also likely that many are lost on private farms, where poisons are used to control problem animals and the vultures fall victim to secondary poisoning.
The iSimangaliso Wetland Park consolidates a number of protected areas previously considered separate parcels of land: St Lucia Game Reserve, False Bay Nature Reserve, St Lucia Park, Cape Vidal State Forest, Sodwana Bay, Sodwana State Forest (now called Ozabeni), Dukuduku State Forest, uMfolozi Swamps State Forest, Mkuze Swamps, Mhlatuze State Forest, Eastern Shores State Forest, Kosi Bay Nature Reserve and Mkhuze Game Reserve. Overall management of the park is the responsibility of the iSimangaliso Authority, although conservation management is under contract to EKZNW.
Extensive work has been undertaken to eradicate the alien plants and pine plantations that used to blanket the Eastern Shores. These have essentially been removed and grassland habitat is being re-established. In addition, iSimangaliso has a mandate to deliver benefits to the land claimants and neighbouring communities as part of a strategy to alter practices that use land and resources unsustainably. iSimangaliso contains four Ramsar sites: the St Lucia Lake System, Turtle Beaches/Coral Reefs of Tongaland, Kosi Bay Lake System and Lake Sibaya. The iSimangaliso Wetland Park received World Heritage Site status in 1999.
From 1992, EKZNW carried out CWACs twice a year from boats and on foot. Since 2003 an aerial census technique has been used, as water levels did not allow boat access. It is hoped that since boating is possible again, there will be a return to previous counting procedures, since they allow for greater resolution of smaller birds, particularly waders. Raptors and vultures in the Mkhuze Game Reserve area are also counted annually during an aerial census.
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