This floodplain becomes a shallow lake every rainy season. This area is important for hydrological control, mostly because there are new transmigration settlement at the down stream. This area located along the Tulang Bawang River from Menggala. The valley in Rawa Tenuk has open seasonal swamps. Mouth of Rawa Tenuk covered by water hyacinth on certain seasons.Originally Tulang Bawang area covers 86000 ha, which located between estuary and Menggala city in Lampung provinve. Around 90% consist of wooden swamp, Melaleuca secondary forest, and almost 10% mangrove forest and remaining riparian forest. Transmigration project in this area has caused 1/4 of mangrove forest converted into agriculture canals. 60% of mangrove forest converted into brackish pond (Giesen 1991)
Important value of this site is known since 1970s for population of Bronze-winged Jacana Metapodius indicus (Marle & Voous 1988). Milky Stork Mycterea cinerea (more than 50 birds) also recorded many times, as well as Lesser Adjutant Leptoptilus javanicu. The populations probably come from Way Kambas & other coastal population.Although herons are common, but other waterbirds in big number always undetected (Giesen 1991, Lambert 1988) until Juny 1993 recorded by D. Holmes; repeated by Wetland International (Noor et.al. 1994. Holmes & Noor 1995) which shown the important value of this site:- Bird colony in Rawa Pacing. In 1994, 45 ha Phragmites support:1. > 60600 Javan Pond-heron Ardeola speciosa2. > 3300 Black-crowned Night-heron Nycticorax nycticorax3. > 2400 Great Egret Egretta alba4. c. 400 Purple Heron Ardea purpurea5. c. 300 Intermedate Egret Egretta intermedia6. c. 100 Cattle Egret Bubulcus ibis7. c. 100 Little Egret Egretta garzettaIt is the biggest breeding area in Indonesia for Javan Pond-heron Ardeola speciosa and Great Egret Egretta alba, and the first place in Sumatra known as night-heron site.- Rantau Kandis colony. In 1994 there were two trees support 48 nest of Oriental Darter Anhingia melanogaster and 9 nest of Grey Heron Arderea cinerea. This area has already disturbed, and this bird colony just established because other bigger colonies around the are has been destroyed. This site was the only site known as Oriental Darter Anhingia melanogaster breeding site.- Rawa Tenuk. This area is one of the area that supports a population of Bronze-winged Jacana Metapodius indicus in Indonesia. In Java this bird has been regarded as extinct as breeding species (van Balen personal comunication). Verheugt et.al. 1993 didn't find this bird in seasonal lake area in South Sumatra, where the bird was predicted to be present there. Rawa Tenuk formerly has White-winged Duck Cairina scutulata (Holmes 1977), but now believed to be extinct because disturbance and loosing nesting area.This site is also important for wetland birds both residence and migrant i.e. Milky Stork Mycterea cinerea and Lesser Adjutant Leptoptilus javanicus, 3 species Ixobycus, Sunda Teal Anas gibberifrons, Cotton Pygmy-Goose Nettapus coromandelianus, cormorant, crake, rail such as Purple Swamphen Porphyrio porphyrio.Formerly this site also supported migrant species Pheasant-tail Jacana Hydrophasianus chirurgus.
Non-bird biodiversity: There are Cervus unicolor, Helarctos malayanus, Macaca fascicularis, Macaca nemestrina and Presbytis cristata in this area (Giesen 1991a)
Habitat and land use
Riverine floodplain and swamp (80%), forest along of river and swamp forest (5%).
Pressure/threats to key biodiversity
Fish catchment, hunting and firewood collection. The military (Indonesian Airforce) has claimed the southern part of Tulang Bawang River as their training area. Irrigation project has made problems such as water quality degradation, sea water intruition and make the soil acid (Giesen 1991a). Reclamation for sugar cane plantation, disturb bird colonies. Egg collection also listed as threats to this site.
This area including Rawa Tenuk, Rawa Bakung, Rawa Bungur, Bawang Belimbing and Bawang Lambu Purus with the total area of 12100 ha has a status as Game Reserve. Meanwhile the area of Rawa Pacing (600 ha) and Rantau Kandis (900 ha) has the status as Nature Reserve.