Ira Lalaro


Lake Ira Lalaro is a waterway in Mehara, Subdistrict Tutuala, Lautém District of East Timor. It is the largest freshwater lake on the island of Timor, and the largest lake in the country of East Timor. The lake is part of the Mount Paitchau Important Bird Area. The lake waters and that of Irasiquero River are a closed aquatic system; they lie within a huge polje. The surface water area fluctuations from while the authigenic catchment area measures.

Geography and geology

Ira Lalaro is in the far east of Timor island, and is part of the Nino Konis Santana National Park (, which was established in August 2007 by East Timor.
The lake is located in a basin bounded by the Paitchau Mountains, within the Lospalos plateau. The region has karstic formations of limestone, with dolines, blind valleys, caves and springs. Ira Lalaro has an average water spread area of, which varies from. It is in a high plateau depression at an elevation of "formed by a huge polje karst formation".
The lake flows to the east and as the lake water recedes during the dry season the land exposed becomes a pasture or scrubby grassland.
The lake basin is surrounded by tropical dry forest which is of biodiversity value. The Irasiquero River, which originates from Lake Ira Lalaru, disappears in the main sink hole, the Mainina, about downstream of the lake outlet, and does not re-appear; tracer studies indicate that the underground route of water flow leads to the coast. There are human settlements in the area.

Biodiversity

The biodiversity of the lake's aquatic system, including the Irasiquero River, is that of a wetland ecosystem. The forest area is largely undisturbed.
In the absence of continuous surface water flow, the invertebrates found in the lake and in the river consist of macroinvertebrate belonging to 57 families but sans decapod crustaceans.
The Island pitviper and wood scorpions are reported in the flood plains of the lake.
Estuarine crocodiles are also found in the lake. It is not hunted by local people as it is their totem animal connected to their creation story and known as "lafaek" in the Tetum language. Boats are banned on the lake, based on a traditional belief that the fish in the lake will die when boats enter the water. Villagers were forced to stand in the water to fish, and fatal crocodile attacks were common. Recently fishermen appear to be using rafts to avoid crocodile attacks. The Timor snake-necked turtle is also endemic to the lake and the river. The local dialect name is ‘‘beo’’, the Tetum name is "lenok kakorok ular" and an alternative English name is Timor long-necked turtle. Chelodina mccordi is considered to be one of the 25 most endangered turtles in the world and is protected under CITES Appendix II.
There are 21 fish species in the lake including an endemic species of hardyhead, found in the middle section of the Irasiquero River.
The lake area has both migratory and resident water birds. It is part of the Mount Paitchau and Lake Ira Lalaro Important Bird Area. One of globally threatened bird species reported is the yellow-crested cockatoo, which is considered critically endangered. Other species reported are: Australian pelican, wandering whistling duck, common coot, Swinhoe's snipe, Australasian grebe, Timor green pigeon, cinnamon-banded kingfisher, spot-breasted white-eye, and black-banded flycatcher. There are 16 species of bats, including Geoffroy's rousette fruit bat, Canut's horseshoe bat, and Sumba round leaf bat.