Lake Chilwa Wetland

Description

The Lake Chilwa is in the Southern Region of Malawi in districts of Machinga, Phalombe and Zomba. The nearest largest town in Zomba which is about 30Km from Kachulu Habour.

The wetland is about 230,000 ha in area with an average altitude of 627 m above sea level. An average rainfall of 1042.9mm per annum for the entire Lake Chilwa catchment was calculated for a thirty year period, i.e. 1961 -1990, by Chavula (1999) with rainy season beginning in November and ending in April. Mean annual temperatures range between 21 -24° C.
The lake and is surrounded by marshes and floodplains. This area is about 40 Km across from east to west and km from North to South. At times of high water level, open water cover about 1,500 km'. The respective areas at times of low water level are 648 km', 699 km', 300 km' and 430 km'. The lake is a closed system with several inflowing rivers but no outlet. As such, water in the wetland is lost through evaporation, transpiration and seepage, and the remainder is what constitutes Lake Chilwa at the end dry season.

Population pressure around the lake is high, with up to 164 people/Km' and an estimated 77,000 people living in the wetland itself. Poverty is high and most people live a subsistence lifestyle growing maize and/or rice. The lake is used extensively for fishing by the local communities throughout the year (Van Zegeren & Wilson, 1997) and during times of food shortage (usually November to March), bird hunting is also carried out to supplement and sustain the food resources of the local population. The birds caught at the lake are either eaten and/or sold for income, As estimated 1,2 million birds are trapped annually by at least 460 trappers, the economic value of which is estimated at US$215,000 (17,2 Million Mk). Currently, there are over 1,300 registered bird hunters who belong to at least 20 bird hunting clubs that form part of the Lake Chilwa Hunters Association which was formed with the aim of sustainably managing the utilisation of sedentary and migratory water birds.

The wetland is under customary land tenure. There is however, management plan that was prepared in 200 J. Lake Chilwa was designated on I" November 1997 as a wetland of international importance (Ramsar site No. 869).

Justification de la Valeur Universelle Exceptionnelle

(ix) Birdlife has identified Lake Chilwa as important for the large congregation of water that occur on its floodplain. It supports a waterfowl population of 354,000 estimated for a selected group of important species (Wison & Zegeren, 1996 & 1998; Wilson 1999) which by far exceeds the 20,000 waterfowl Ramsar criteria. The Lake and its associated wetland supports about 164 bird species, 43 of which are seasonal and long term changes in lake level have major impacts on floodplain inundation and consequently on waterbird populations. The six of the wetland habitats vary depending on the level of the lake which fluctuates seasonally; the lake has dried up on seven occasions in the century (Kabwazi & Wison, 1998).

(x) The lake covers approximately 2,300km' and comprises 2,077 km' of natural habitats (open water, Typha swamp, marshes and floodplain grassland) and 233 km' of cultivated areas (wetland rice, irrigated rice and dimba). The Typha swamp is extensive, ranging from 5 km² wide bands along the western margin up to 17 km stretches in the northern marshes. One wetland-dependent bird species of global concern occurs regularly in significant numbers -the African skimmer (Rynchops flavirostris), Birdlife International (2002). The wetland also holds populations of the vulnerable lesser kestrel (Falco naumanii), the locally rare pallid harrier (Circus macrourus) and great snipe (Gallinapo media).

Because the wetland is under customary tenure, the government of Malawi with the assistance of the Danish Hunters Association is in the process of creating a Community Conservation Area in Lake Chilwa. The wetland has also been proposed for a biosphere reserve. All these initiatives will ensure conservation in the long term.

Comparaison avec d’autres biens similaires

There are a number of wetlands outside Malawi that are similar to Lake Chilwa such as iSimangaliso Wetland Park" formerly St Lucia Wetlands of South Africa and Area of Colchis wetlands and forests of Georgia both of which are also Ramsar sites. Whereas iSimangaliso has over 500 different species of marine, wetland and forest birds resident Or pass through the wetland system annually, the park is unique due to its having one of the most diverse variety of frogs and their choruses can often be heard at night and on dull rainy days. The highly endangered gaboon adder and a large variety of other snake species reside in this subtropical coastal dune forest. Area of Colchis wetlands and forests is one of the last remains of the landscape belt, rich in tropical and sub-tropical habitats, which existed some ten million years ago and stretched as an almost unbroken line over the vast Eurasian continent. It is unique territory
due to its biodiversity, wetlands and forest ecosystems variety, high endemism, richness in relics of the tertiary period and especial objects of geological and paleontological importance.

Lake Chilwa on the other hand is one of the few Wetlands in Africa that supports a waterfowl population of 354,000 estimated for a selected group of important species (Wison & Zegeren, 1996 & 1998; Wilson 1999) which by far exceeds the 20,000 waterfowl Ramsar criteria, wetland dependant bird-species -the Rynchops flaviroslris as well as populations of the vulnerable Falco naumanii the locally rare Circus macrourus and Gallinapo media. It is probably the only one with an estimated 77,000 people living in the wetland itself, 233 km' of cultivated areas (wetland rice, irrigated rice and dimba) and bird hunting to supplement and sustain the food resources of the local population creating a unique interdependence between the environment and human beings.