Perairan Sungai Mahakam
Location:
0°07'-0°29'S, 116°03'-116°52'E; in the Mahakam Valley, 90 km west of Samarinda, Kabupaten Kutai, East Kalimantan.
Area:
200,000 ha.
Altitude:
20- l00m.
Biogeographical Province:
4.25.12.
Wetland type:
10, 11, 13, 14 & 21.
Description of site:
A vast complex of freshwater lakes, swamps and interconnecting channels in the Mahakam River valley, with surrounding freshwater swamp forests (30,000 ha) and peat swamp forests (10,000 ha). The lakes cover an area of about 15,000 ha. The largest is Semayang Melintang; other smaller lakes include Batu Bumbus (450 ha), Lokang (400 ha), Siran (750 ha) and Jantur (200 ha). The area is inhabited by large numbers of people and the river is important for transport.
Climatic conditions:
Humid tropical climate with an average annual rainfall of 2,000 mm. The mean temperature is 30°C.
Principal vegetation:
Freshwater swamp forest and peat swamp forest. Eichhornia crassipes is common in the lakes.
Land tenure:
State owned (Indonesian Government).
Conservation measures taken:
None.
Conservation measures proposed:
The entire area has been proposed as a Nature Reserve (Cagar Alam). However, because of the high level of human settlement, a more modest proposal may be required (MacKinnon & Artha, 1981a). Laud
Land use:
Fishing; forestry in surrounding areas.
Disturbances and threats:
There is a considerable amount of disturbance from heavy shipping (logging boats and rafts) on the river. Other threats include pollution, over-fishing, human encroachment and the catching of freshwater dolphins Orcaella brevirostris.
Economic and social values:
The lakes support a major inland fishery.
Fauna:
The rich fish fauna includes Mystus nemurus, Helastoma temmincki, Ophiocephalus striatus, Pristis sp, Laptabarbus haerani, Clarias batrachus, Anabas sp, Puntius sp, Dasyatis sp and Pangasius sp.
The lakes are said to be of considerable importance for waterbirds, but few data are available. Species known to occur include Ardeola sp, Egretta intermedia, Leptoptilos javanicus, Gojlinula chioropus and Sterna albifrons. Seven White-shouldered Ibises Pseudibis davidsoni were recorded in October 1983.
The Mahakam River is inhabited by a distinct subspecies of the rare Irrawaddy or Snubfin Dolphin Orcaella brevirostris. Other mammals include Macaca fascicularis, Nasalis larvatus, Hylobazes sp, Neofelis brevirosris, N. nebulosa, Helarctos malayanus, Cervus unicolor and Sus barbatus.
Special floral values:
No information.
References:
Holmes & Burton (1987); Kanwil Departemen Kehutanan Kalimantan Timur (1984); MacKinnon & Artha (1981a).
Criteria for Inclusion:
1b, 1e, 2a, 2b, 2d, 3b.
Source:
Marcel J. Silvius.