Protected Areas and World Heritage Programme

NAME Rano Raraku

LOCATION 27^o09'S, 109^o27'W; near the eastern end of Isla de Pascua (Easter Island).

AREA 10 ha.

ALTITUDE 50 m.

OVERVIEW A small freshwater crater lake with extensive emergent aquatic vegetation.

PHYSICAL FEATURES A freshwater lake in the crater of Rano Raraku volcano, roughly cirucular in shape and approximately 350 m in diameter. The lake, which has a volume of 206,100 cubic metres, is fed by local run-off. The pH of the water is 7.15.

The climate is equatorial-oceanic, with an average annual rainfall of 1,126 mm and a mean annual temperature of 20.7^oC. March to June are the wettest months, and July to October the driest and coolest. Southeast trade winds dominate from October to April; during the rest of the year North and Northwest winds are more common.

ECOLOGICAL FEATURES The lake is fringed with stands of Polygonum and Scirpus californicus which cover 45% of the surface, mostly in the southern third of the lake, and there are floating mats of the endemic moss Campylopus turficola.

LAND TENURE State owned (Chilean Government).

CONSERVATION MEASURES TAKEN Protected within Rapa Nui National Park (4,755 ha) established in 1935 by Decree 103, Ministry of Lands and Colonization. A management plan for the park was published with the assistance of FAO in 1976 (Zentilli et al, 1976).

LAND USE Water supply and tourism. A pipe takes water from the lake to a nearby homestead. Domestic livestock visit the lake to drink.

DISTURBANCES AND THREATS Erosion, uncontrolled fires and damage caused by tourists may pose problems to the wetland. Islanders do not recognise the Chilean Government's authority to declare their lands a national park and consequently respect few of its rules (UNEP/IUCN, 1988).

HYDROLOGICAL AND BIOPHYSICAL VALUES No information.

SOCIAL AND CULTURAL VALUES The southern wall of the volcano was the quarry for most of the stone statues (moai) for which Easter Island is famous. About 200 statues remain in the quarry, in various stages of completion.

NOTEWORTHY FAUNA No waterbirds are known to have occurred at the lake (or indeed on Easter Island). Large numbers of introduced Common Diuca Finches (Diuca diuca) and House Sparrows (Passer domesticus) utilise the reed beds, while introduced Chimango Caracaras (Milvago chimango) and Chilean Tinamous (Nothoprocta perdicaria) occur in the area. Dragonflies (Neuroptera) are present.

NOTEWORTHY FLORA An endemic moss, Campylopus turficola, is present.

SCIENTIFIC RESEARCH AND FACILITIES Limnological research is being carried out in the crater lakes in the National Park (Steffen and Palma, 1992), but no studies have been made of the fauna and flora of the wetlands. A research laboratory is currently being constructed.

RECREATION AND TOURISM The quarry in the southern wall of the crater is frequently visited by tourists.

MANAGEMENT AUTHORITY AND JURISDICTION Corporacion Nacional Forestal.

REFERENCES Dahl (1986); IUCN (1991); UNEP/IUCN (1988); Steffen & Palma (1992); Zentilli et al, 1976.

REASONS FOR INCLUSION 1a, 2b. Rano Raraku and the other two freshwater lakes of Easter Island are of considerable interest because of their extreme isolation.

SOURCE Roberto P. Schlatter, Wladimir Steffen and Roger Hicks.