Home Wetlands in South Africa Ramsar Sites Definition of a Wetland
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This
wetland became part of the Ramsar Convention on the 25th of
April 1988.
The Langebaan Lagoon (approximately 6 000ha) is situated on the
west coast of South Africa, within the West Coast National Park
(approximately 27 000ha) about 100 km northwest of Cape Town (33°06'S,
18°01' E), adjoining the coastal village of Langebaan. |
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The
Langebaan Lagoon comprises:
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Classification
of these wetlands includes:
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| Land uses Top | ||||||
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The
entire inter- and subtidal lagoon and approximately 70 percent of the
land on its immediate perimeter is controlled by National Parks Board
and private contractual parks. The rest is owned by the South African
Defence Force, |
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The
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Natural: | |||||
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The
lagoon is divided into three different utilization zones namely:
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| Agricultural: | ||||||
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Farming
activities inland do not significantly influence the lagoon system. |
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| The
aquaculture farm, Atlans Farms grows the alien mussel Mytilys
galloprovincialis and oysters Crassotrea sp. from
floating rafts anchored in |
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| Further
inland several farms produce a variety of items, such as potatoes,
wheat, sheep, cattle and pig. |
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| Industrial: | ||||||
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The
larger Saldanha town (15 km from Langebaan) has a large commercial
fishing harbour and tow fish processing factories. |
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The nearby Saldanha-Sishen terminal is used for loading iron ore and
unloading crude oil. |
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| Casts of the alga Gracilaria verrucosa are collected from the beaches just north of the lagoon for commercial gain. | ||||||
| Urban: | ||||||
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The
Langebaan Lagoon is adjacent to the village Langebaan and closer to
the lagoon’s entrance to the sea, is the larger town of |
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| Recreational: | ||||||
| The
Langebaan Lagoon - |
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| Ecology Top | ||||||
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In
1995, the main habitat and vegetation types of the lagoon were:
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| Algae: | ||||||
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Over
71 species of marine algae (13 Chlorophyta, 10 Phaeophyta and 48
Rhodophyta) have been recorded in the Saldanha Bay-Langebaan Lagoon
area. The more common species are Ulva spp., Ecklonia maxima,
Laminaria pallida, Aeodes orbitosa, Gigartina radula, Gracilaria
verrucosa and Porphyra capensis (Ref. 3). |
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| Vegetation: | ||||||
| Aquatic vegetation: | ||||||
| Extensive marshlands occur along the south-eastern edges of the lagoon. The dominant species (Arthrocnemum pillanssi var. pillanssi, Salicornia capensis and Disphyma crassifolium, Juncus krausii, Scirpus nodosus, Nidorella foetida, Senecio Haliminfolius, Typha capensis and Phragmites australis) are generally common in marshlands throughout the region | ||||||
| Terrestrial Vegetation: | ||||||
| Most
of the other plant communities bordering the lagoon belong to the West
Coast Strandveld and the park conserves about 12 percent of this
"threatened" vegetation type (Ref. 1 and 2). The dominant
plants include Atriplex semibaccata, Drosanthemum floribundum,
Zygophyllum morgsana, Z. cordifoloum, Z. flexuosum, Rushia
geminiflora, Mesembryanthemum crystallinum, Rhus glauca, R.
longispina, Ehrharta erecta, E. calycina, Senecio floribunda, Rushia
geminiflora, Euphorbia mauretanica, Salvia lanceolata, Willdenowia
striata, Ericocephalus africanus, Putterlickia pyracantha and Euclea
racemosa. |
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| The
iris Moraea loubseri is probably extinct from its natural
habitat, while possibly threatened species are: Vanizijlia
rostella, Hessea chaplinii, H. mathewsii, Felicia elongata, Pauridia
longituba, Ferraria langebaanensis, Geissorhiza lewisae, Gladiolus
gracilis var latifolius, Ixia purpureorosea, Romulea
elliptica, R. saldanhensis, Watsonia hysterantha, Hyacinthus
paucifolius, Lachenalia viridiflora, Oxalis subsessilis, O. burtoniae,
Muraltia harveyana, Leucospermum tomentosum and Agathosma
thymifolia (Ref.1). |
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| Invertebrates: | ||||||
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The invertebrate fauna of the
intertidal mudflats are an important food source for waders. The snail
Assiminea
globulus, which comprises about 62,5 percent of the
invertebrate biomass in the surface layers of the intertidal mudflats
(Ref. 4), is the major prey item of the dominant curlew sandpiper
(Ref. 5). The deeper burrowing mud prawn Upogebia
africana is important to the kelp gull (Larus
dominicanus), grey plover (Pluvialis
squatarola), whimbrel (Numenius
phaeopus) and common tern (Sterna
hirundo) (Ref. 6), while the sand prawn (Callianassa
kraussi) is the bait organism most frequently used by anglers
in the lagoon (Ref.
7). |
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| Fish: | ||||||
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Fish
populations in the lagoon are generally low, Gobies (Gobiidae) and
clinids (Clinidae), pipefish (Syngnathidae) and Cape silverside (Antherina
Breviceps) are common in the weed beds, while shoals of the
southern mullet (Liza richardsoni) and maasbanker (Trachurus
trachurus) often frequent the deeper, sandier area of the lagoon
(Ref. 8). Other important fish species in the lagoon are the West
Coast streenbras (Lithognathus aureti), white stumpnose (Rhadosargus
globiceps), steentjie (Spondyliosoma emarginatum),
hottentot (Pachymetopon blochi) and sand shark (Rhinobatos
annulatus). |
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| Reptiles and Amphibians: | ||||||
| Birds: | ||||||
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Furthermore
some 400 (or 12 percent of the world's population of) African black
oystercatcher (Haematopus moguini) are found in the Langebaan
area (Ref. 12 and 13). |
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The
most recent results are available from the Avian Demography Unit (ADU)
at |
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The
Sea Fisheries Research Institute counted pairs of seabirds breeding at
the islands in the |
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| Mammals: | ||||||
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Compared
with the more tropical regions of southern Africa, the |
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| Topography and geology Top | |||||
| Topography and geography: | |||||
| The
average depth of the Langebaan Lagoon, which is 2 - 6 m, does not vary
with seasons. |
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| Geology: | |||||
| The three major substrata are limestone, granite and sand - all of natural origin | |||||
| Soils:
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| Fine, unconsolidated quartzitic sand, poor in nutrients, underlies most of the lagoon | |||||
| Hydrology and geohydrology Top | |||||
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The
lagoon, which is perennial and entirely marine, has a strong tidal
exchange with no marked seasonal variation in flow. |
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The
lagoon is an open marine system and the effect of freshwater flooding
is small. |
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No major rivers discharge into the lagoon, but fresh-water does drain from the surrounding catchment area and collects in the Juncus krausii marshes along the southern end of the lagoon. These marshlands and eelgrass beds in the lagoon act as sediment traps, and freshwater flooding after rain does not significantly affect the system. Water quality and "nutrient" transport in the lagoon is maintained by a strong tidal exchange of seawater. Current speeds in the middle section of the lagoon are about 20 cm per second, and approximately 12 percent of the volume of the lagoon-bay system is exchanged during a spring tide (Ref. 15). Erosion along the banks of the lagoon is minimal, but unconsolidated sand dunes nearby have been "stabilized" through intensive planting of indigenous vegetation. | ||||
| Climate Top | |||||
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Precipitation: | ||||
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Temperature: | ||||
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The ranges in the mean monthly minimum and maximum temperatures are ±8,7 - 17,1 ºC and 14,6 - 21,0 ºC respectively | ||||
| Threats Top | |||||
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The
Saldanha-Sishen terminal has the potential of "causing" a
major oil spill, as well as long-term, windblown, ore dust pollution,
and thereby the food source of the waders. Likewise, commercial
fishing activities in the seabird colonies and recreational activities
in the area could become a major disturbance factor. |
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Numerous factors have
negatively impacted on the ecology of the lagoon. These are:
Despite these activities the ecosystem is still intact and healthy. |
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| References Top | |||||
| Ref 1:
BOUCHER,
C. and JARMAN, M.L. (1977). The vegetation of the Langebaan area, |
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| Ref 2: JARMAN,
M.L. (Ed) 1986. Conservation priorities in lowland regions of the
fynbos biome. South African national scientific Programme Report
No 87. CSIR, |
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| Ref 3: SIMONS,
R.H. (1977). The algal flora of |
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| Ref
4: PUTTICK,
G.M. 1977. Spatial and temporal variations in intertidal animal
distribution at |
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| Ref
5: PUTTICK,
G.M. 1980. Energy budgets of Curlew Sandpipers at |
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| Ref 6: Martin J.L. (1991) The Parus caeruleus complex revisited. ARDEA 79 (3) : 429 - 438 | |||||
| Ref
7:
WYNBERG,
R.P. & BRANCH G.M. 1991. An assessment of bait-collecting for Callianassa
kraussi Stebbing in |
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| Ref
8:
http://www.environment.gov.za/Branches/BioConservation/17Ramsar/langebaan/langebaan_ris.htm |
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| Ref
9: UNDERHILL,
L.G. (1987). Waders (Charadrii) and other waterbirds at |
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| Ref
10: BERRUTI,
A. (1989). Resident seabirds. In. Oceans of Life off |
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| Ref
11: COOPER,
J., CRAWFORD, R.J.M., SUTER, W. & WILLIAMS, A.J. (1990).
Distribution, population size and conservation of the swift tern Sterna
bergii in southern |
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| Ref 12: HOCKEY, P.A.R. (1983). The distribution, population movement and conservation of the African black Oystercatcher Haematopus moquini. Biological Conservation 25: 233 - 262 | |||||
| Ref
13: HOCKEY,
P.A.R. (1985). Haematopus ostralegus in perspective: a review
of the world's oystercatchers. In: Goss-Custard, J.D. (Ed.).
Ecology of the eurasian Oystercatcher: from individuals to
populations. |
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| Ref
14: AVERY,
D.M., RAUTENBACH, I.L. & RANDALL, R.M. (1990). An annotated check
list of the land mammal fauna of the |
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| Ref
15: SHANNON,
L.V. & STANDER G.M. (1977). Physical and chemical characteristics
of water in |
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| Useful links Top | |||||
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