Country/territory: South Africa
IBA Criteria met: A1, A2, A3, A4i, A4iii (1998)
For more information about IBA criteria please click here
Area: 167,700 ha
Protection status:
Most recent IBA monitoring assessment | |||
---|---|---|---|
Year of assessment | Threat score (pressure) | Condition score (state) | Action score (response) |
2013 | very high | not assessed | high |
For more information about IBA monitoring please click here |
Site description
Situated c.80 km north of Richards Bay, Lake St Lucia is a subtropical coastal estuary with a long narrow channel to the sea. Located on the north-eastern KwaZulu-Natal coastal plain, the system is bounded by the Umfolozi river and its associated swamps in the south, and by the Mkuze river and Ozabeni in the north. The lake system is about 70 km long, and, excluding The Narrows, between 3 km and 18 km wide for most of its length. It is the largest estuarine system in Africa, with a water surface area that varies from 225–417 km². The mean depth is less than 1 m, and the water turbidity is high because the substrate is mainly fine silt. Hydrological conditions in the lake vary seasonally and in the long-term, with long periods of hypersalinity that result in large changes in the composition and abundance of plant, invertebrate and bird species.
Key biodiversity
See Box and Tables 2 and 3 for key species. The St Lucia system supports over 350 bird species and is the most important breeding area for waterbirds in South Africa, with at least 48 breeding species recorded. Owing to its subtropical position, several bird species reach the southern limits of their ranges at St Lucia. Owing to the variability of the system, the lake may often hold very important numbers of a species in some years and almost insignificant numbers in others. At times, Lake St Lucia holds extremely large numbers of Pelecanus rufescens, P. onocrotalus, Platalea alba, Anas smithii, A. undulata, Recurvirostra avosetta and Phoenicopterus minor. Phoenicopterus ruber bred here in 1972, when some 30,000 birds and 6,000 nests were recorded owing to an increase in food, produced by a period of low salinity that followed a long hyper-saline period. St Lucia also holds the only breeding population of Ephippiorhynchus senegalensis in KwaZulu-Natal and is one of only three breeding sites for Mycteria ibis in KwaZulu-Natal. The lake can hold over 80% of South Africa’s breeding population of Sterna caspia. The colony of Pelecanus onocrotalus is the only known breeding colony in south-east Africa. Large numbers of Palearctic migrant waders occur in summer.
Non-bird biodiversity: As befits a World Heritage Site, St Lucia has a wealth of Red Data and endemic species. Endemic to the IBA are the plants Kalanchoe luciae, Rhus kwazuluana and a new species of Aloe, and five species of butterfly. The mammal Diceros bicornis (CR) has been reintroduced.
Recommended citation
BirdLife International (2021) Important Bird Areas factsheet: Lake St Lucia and Mkuze Swamps. Downloaded from
http://www.birdlife.org on 17/01/2021.