Included here is Borneo (Kalimantan) and adjacent islands such the Bunguran (Natuna) Islands, Calamian Islands, Jolo Island, Laut Island, Palawan Island, Pangutaran Islands and the Tawitawi Islands.

Bornean Swamp Forest

These can be divided into rain-fed peat swamp forests and river-fed swamp forests. The ones fed by rainwater are less nutrient rich and generally less species rich than adjacent river water swamps. Peat swamp forests are widespread occurring in the lowlands of Kalimantan and on the coastal plains of Brunei and Sarawak - the largest being on the Maludam Peninsula. Some of these are thought to have been established for many thousands of years and in places have developed a peat layer up to 20 m thick. The dominant trees vary from place to place, but in a number of peat swamps including those of the Maludam Peninsula, the endemic Shorea albida (Dipterocarpaceae) is dominant. Other trees may include Dyera costulata, Gonystylus bancanus and several endemic taxa such as Adenanthera malagana subsp andersonii, Albizia dolichadena (Fabaceae), Lophopetalum sessilifolium (Celastraceae), Prunus turfosa (Rosaceae), Xanthophyllum ramiflorum (Polygalaceae), and on the edges of peat swamps the endemic Shorea balangeran (Diperocarpaceae). Several of these trees have prominent aerial roots (pneumatophores) for obtaining oxygen in waterlogged conditions. Another feature of these low nutrient forests is the presence of many plants with supplementary means of nutrition such as the ant plants Hydnophyton and Myrmecodia and pitcher plants. River swamp forests are mostly associated with huge low-lying river basins and there are extensive examples occurring in the southwest of Borneo.

They are typically more species rich and taller than peat swamp forests reaching heights of 35 m. Their species composition is very mixed but some of the more important trees include Cerbera manghas, Dracontomelon puberulum, Heritiera littoralis, Initsia palembanica, Lagerstromia speciosa, the endemic dipterocarps Shorea macrophylla and S. splendida (Dipterocarpaceae) and the Bornean ironwood Eusideroxylon zwageri (Lauraceae). Other endemic trees include Archidendron fagifolium var. borneense (Fabaceae), Chisocheton lansiifolius (Meliaceae), Copaifera palustris (Caesalpiniaceae), Dacrycarpus steupii (Podocarpaceae), Dactylocladus stenostachys (Crypteroniaceae), Dipterocarpus tempehes and Hopea pentanervia (Dipterocarpaceae), Dryobalanops rappa (Dipterocarpaceae), Horsfieldia carnosa (Myristicaceae), Knema uliginosa (Myristicaeae), Lepisanthes divaricata (Sapindaceae), Lithocarpus andersonii (Fagaceae), Lophopetalum sessilifolium (Celastraceae), Magnolia lasia (Magnoliaceae), Prunus turfosa (Rosaceae) and Semecarpus glaucus (Anacardiaceae). Among the endemic shrubs are Arthrophyllum crassum (Araliaceae), Diplycosia lavandulifera, Rhododendron commutatum and Vaccinium costerifolium (Ericaceae). There are also a number of epiphytic shrubs such as the endemic Diplycosia carrii (Ericaceae) and a few lianas and climbers like to endemic Gnetum neglectum (Gnetaceae). Included among the many epiphytes is the endemic fern Drynaria involuta (Polypodiaceae). Not surprisingly, the permanently saturated or flooded ground layer includes many hydrophytes and hygrophytes such as the endemic sedge Mapania maschalina (Cyperaceae).

References

Bruenig, E. F. 1990. Oligotrophic forested wetlands in Borneo. In: Ecosystems of the World 15. Forested Wetlands. Eds. A. Lugo, M. Brinson and S. Brown. Elsevier.

MacKinnon, K., Hatta, G., Halim, H. & Mangalik, A. 1997. The Ecology of Kalimantan. Oxford University Press.

Phillips, V. D. 1998. Peatswamp ecology and sustainable development in Borneo. Biodiversity and Conservation, 7: 651-671.

Steenis, C. G. G. J. van. 1957. Outline of the vegetation types in Indonesia and some adjacent regions. Proceedings of the Pacific Scientific Congress, 8: 61-97.