Borneo Island and ecological enviros

Borneo is the third largest island after Greenland and New Guinea but is comparatively very rich in biodiversity compared to any other regions (Cranbrook and Edward 1996, MacKinnon et al., 1997). The land covering 746337 km2 extends from latitude 7o N to 4o S and longitude 109o  to 119o E. The island is politically divided into three countries, namely, four provinces in Kalimantan (72.2%), Indonesia, Sabah and Sarawak in Malaysia (27%) and Brunei (0.8%). The coastal lowland areas are dominated by tidal and fresh water swamps. The centrally located mountain ranges run diagonally dividing the river systems to drain into four different directions. The mountain ranges also form a natural physical boundary separating Malaysian and Indonesian Borneo as well as between Sabah and Sarawak. At the height of 4,101 m, Mount Kinabalu that is located in Sabah is the highest mountain in Southeast Asia. The mountain ranges also form the natural physical boundary separating the Malaysian and Indonesian Borneo. Some of the long navigable rivers are Kapuas (1,143 km), Barito (900 km) and Mahakam (775 km) in Kalimantan, Rejang in Sarawak and Kinabatangan in Sabah.

There are about 15,000 species of flowering plants with 3,000 species of trees (267 species of dipterocarps), 221 species of mammals (excluding cetaceans) and 420 species of resident birds in Borneo (Kostermans 1987; MacKinnon et al., 1997). In contrast to this high diversity, the vast Europe regions have only 134 species of mammals including some introduced species (Corbet and Harris 1991). Biogeographically, the flora and faunal distribution is influenced many factors such as geological history, altitude, soil and habitat types. Based on the phytogeographical distribution, MacKinnon et al., (1997) classified  the island proper into seven distinct biogeographical regions, namely; (1) the Meratus Mountain of South Kalimantan with high plant species-richness and endemism, (2) the northeast region with distinct phytogeography, (3) the plant species rich region of north coast including Brunei and eastern Sarawak, (4) the ancient hills of north-west Borneo north of the Kapuas River and including western Sarawak, (5) the southern lowland plain with vast species-poor peat swamp and freshwater swamp forests, (6) the drier east coast of Borneo and (7) the little-explored hills and mountains in central of Borneo .

The ecological balances of the rainforest in Borneo are affected by hunting and shifting cultivation which are culturally and traditionally important way of live among the local community (Abdullah 1996, MacKinnon et al., 1997). These activities among the poor villagers play important role in the rural socio-economy for self-employment and subsistence. According to Firman (1996), the Dayaks and Ibans have a long history in the traditional shifting (swidden, non-sedentary or slash-and-burn agriculture) cultivation practice in Borneo. The practice is characterised by the rotation of planting fields which is accompanied by slashing and burning of the primary forest. New field is cleared and burnt in May to August by co-operative groups of ten families. Cultivation in the form of rain-fed rice followed by corn, chilli, and vegetables. After one crop cycle the field is left to fallow on average of six years or regenerate into secondary forest. Fruit trees, banana and  rubber are planted to establish ownership of the land. The secondary forests from the old fields also become sources for food, fruit, wild animal, plants, fuel and building materials.

The history of human civilisation started as early as 40,000 to 10,000 years ago in the Niah Cave in Sarawak. According to Medway (1979),  the prehistoric cave-man hunted animals (including 55 species of wild animals), fished and collected fruits and tubers from the forest. From the prehistoric beginning until the present day, consumptive use of wildlife is culturally and traditionally an important activity among the Bornean communities (Abdullah 1996, Medway 1979). Wildlife utilisation involved species of amphibians, reptiles, birds and mammals. Generally, in a year, a local longhouse community in Borneo consumed wild meat at the rate of about 50 kg per person. In Sarawak, modern refrigeration facilities had enabled the local communities living along the forest fringes to store excess wild meat from successful huntings for future consumption as well as for sale within the communities or for more lucrative markets in the cities (Abdullah 1996).

The present land use pattern which is also influenced by the acceleration of economic activities on the island (MacKinnon et al., 1997). Borneo is primarily a market economy depending heavily on the export of forestry products, oil and petroleum, gas, minerals as well as tourism. Although the population density is relatively low, averaging 16 persons/km2 compared to density of 830 persons/km2 on Java Island, the natural Bornean landscape is rapidly changing. Bruening (1996), MacKinnon et al., (1997)  and Whitmore and Sayer (1992) provided excellent reviews on the extensive forest exploitation in Borneo and its destructive effects on the physical and biological environments. Decades of extensive commercial logging had claimed most of the lowland and swamp forest. Later some logged-over forests were clear felled for agriculture or left as waste land. Major mono-agricultural plantations of oil palm (Elaeis guineensis), cocoa and rubber (Hevea brasiliensis) are relatively well developed in the Malaysian Borneo. The traditional longhouse communities practised shifting cultivation that is also responsible to the deforestation process. Anthropogenic habitat disturbances such as land clearance for infrastructure projects (e.g., highways and dams), urbanisation, human settlement and transmigration also contributed to the rapid deforestation process of the tropical rainforest on Borneo Island. Prolonged and severe droughts had occurred several times in Borneo between 1972-73, 1982-83 and 1987 which was related to the El Niño Southern Oscillation (MacKinnon et al., 1997; Walsh 1996). Forest fire occurring during drought also caused some ecological changes in the distribution pattern of fauna and flora (Kostermans 1987; Tajawa and Wirawan 1988).

Rainfall averaging  2,250 to 4,280 mm in Sabah and Sarawak. Relative humidity is high averaging between 90% and emperature varies between 24o  C to 32o C with annual variation between 1o and 3o the lowland and 22o and 27o C in the highland. In  Sarawak the chance of rain is high with 253 days of rainfall in Kuching (Annon 1992).