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The state of conservation areas in the region
A great deal depends on the success with which the conservation forests and wildlife sanctuaries, either declared or proposed, are sus tained. Those already declared constitute an area equal to 7.7 per cent of the estimated remaining forest area in the region as a whole; those proposed add a further 9.6 per cent. However, some conservation areas include significant non-forest tracts (from tabulated data in Collins, Sayer, and Whitmore, 1991: 146, 162, 185, 188, 203, 208). There are also designated watershed areas, the protection status of which is uncertain. In the montane regions, where some large existing or proposed conservation areas occur in both East Malaysia and Kalimantan, development pressure is generally light, though parts of the Kinabalu National Park in Sabah have been excised for agriculture, recreation, and mining, and others have been invaded by farmers. One large upland area, Kayan Mentarang in Kalimantan, already has a farming population of around 10,000. The aim is to develop this area as a biosphere reserve, which may include humanmodified ecosystems in addition to undisturbed natural areas. Its boundaries have already been extended to include tracts of lowland dipterocarp forest as well as the upland systems. As the largest protected block of rain forest in South-East Asia (1.6 million ha), it is vitally important as a refuge for rare and endemic species (Jessup, Soedjito, and Kartawinata, 1992). Conservation fieldwork has just begun in this region; it has a longer history in other near-coastal and coastal reserves recognized early for their large tracts of lowland dipterocarp forest.
Two of the largest lowland conservation areas, Taman Negara (National Park) in the Peninsula and Kutai National Park in East Kalimantan, were first designated in the colonial period, as was Gunung Palung in West Kalimantan. Taman Negara was designated in 1935, and its integrity was confirmed in the 1970s after a decision was taken not to proceed with a major dam that would have invaded its boundaries (Collins, Sayer, and Whitmore, 1991: 188; Government of Malaysia, 1976). With an area of over 430,000 ha, Taman Negara protects montane as well as lowland forest. There continues, however, to be some doubt about the security of the lowland area; planned tourist road development might renew pressure from logging, illegal if not legal. In the case of Kutai, a reserve of 2 million ha was proposed for wildlife preservation in 1932 (Wirawan, 1993), corresponding with the distributional limits of concentrations of orangutan and the Sumatran rhinoceros, with a full range of Malesian plant life, and with many other animal and bird species. The area actually approved in 1936 by the Sultan of Kutai and the Dutch government was, however, only 306,000 ha, and the park was further reduced in
1971 to 200,000 ha after a significant part of it had already been logged. Numerous studies have been conducted in this reserve (summarized by Wirawan, 1985), and they show that all the large mammals intended to be protected in the 1930s, except the Sumatran rhinoceros, were still present, together with a great richness of bird species and smaller ungulates, carnivores, and primates.
Kutai was partly burned in the 1982/83 fires (chap. 8), but about half remained undamaged. The fire killed 52 per cent of the fruit trees belonging to the Meliaceae and Myrtaceae, and many members of the 50 species of Lauraceae trees were lost (Wirawan, 1993), with serious consequences for the birds and animals dependent on these food sources. However, significant biological resources still remain. Provided these and other large areas can be conserved and protected from illegal logging and other invasion, a genetic pool of biodiversity in the lowland forests might yet survive. For most of the lowlands, however, there is no hope of restoring the full diversity of biota and fauna that existed not long ago.2
A question of management
All over the world, it is increasingly recognized that conservation areas from which people are excluded tend quickly to be poached, and can be sustained only by a heavy and costly programme of management and policing. On the other hand, conservation areas in which small numbers of people live, farm, hunt, and forage are usually more successful; they are managed by the people themselves. This relatively new philosophy of biodiversity conservation has yet to win general acceptance, but it is being tried in Indonesia, where it receives at least lip-service from the Forestry Department.
The Natural Resources Management Project, a joint venture of the United States Agency for International Development (USAID) and the Government of Indonesia, is attempting to institute this kind of management in the Bukit Baka/Bukit Raya National Park straddling the border of West and Central Kalimantan. This is a typical upland park in the Schwaner mountains. The location is remote, the surrounding Dayak population is not large, and threats to its integrity come mainly from logging companies. Little is known in detail about the flora and fauna apart from a short survey of Bukit Raya by a Dutch biologist in 1982/83 (Nooteboom, 1987). A team from the Indonesian Institute of Sciences (LIPI) has plans to make a more comprehensive survey. A management plan has been drawn up for the park, incorporating some aspects of local involvement (Potess, 1992). If it is successful, a similar system will be tried in the more difficult environment of Gunung Palung, which is being subjected to many more outside stresses than is Bukit Baka/Raya, despite the absence of hunting pressures on the wildlife (Potter, 1992). It seems clear, however, that a devolution of responsibility for park management to local interests is the only way to ensure some kind of protection of these immensely valuable resources, while allowing local people controlled extraction rights in limited areas. As pointed out, such an approach is still experimental and there are many aspects to be worked through in detail.
Meanwhile, on the part of those in government in all the territories concerned, there is a new awareness of the importance of conserving portions of the remaining forests before it is too late. It is an awareness shared by the scientific community, both national and international, who are fearful that, if no workable formula is found for their administration, the parks and reserves will be seen as jewels for the plundering by an unscrupulous minority, and the last chance for conserving the amazing biodiversity of Malesia will be irrevocably lost.
1. These multi-purpose tree gardens, or "complex
agroforests," are further discussed in chapter 6.
2. One very recent example is a wildlife reserve of 35,000 ha in South Kalimantan (Pleihari-Tanah Laut), which has recently been reclassified because animal populations are stated to have dropped so much that it is not worth retaining. The swamp forest was said to have been invaded by shifting cultivators, cattle grazers, and shrimp fishermen. Parts are scheduled to be planted up in fast-growing exotic tree species (Kompas, 30 April 1992; 8 May 1992; 7 July 1992).
Whereas biodiversity is a major issue on the international plane and so, in a different way, is the effect of forest loss on the forest people, there are other issues that are of greater significance to most people living within the region. These are the effects of rapid forest transformation on the land and the rivers, and the viability of the new economies that have come into being dependent on, and in place of, the forest. These more regional questions form the topic of this chapter.
The effect of clearance on hydrology and soil
It is a general finding that forests offer the best protection that the land can have from erosion. The burden of almost all research into erosion and hydrology in recent years confirms that, although it is wrong to assume that no erosion takes place under forest, there is a jump of major order once the forest is cleared. In undisturbed forest, raindrop impact is greatly reduced by the canopy, and infiltration through the litter into the weathered regolith is high. Not more than about 5 per cent of water reaching the forest floor becomes overland flow, and most runoff at base flow reaches the streams through the shallow water table (Douglas et al., 1992b: 404). It is for this reason that slope failure is the most common form of erosion in hills under closed fores.šEven so, with storm rainfall registering 30-minute intensities up to 100 mm/hour, the amount of debris and sediment carried into and down the streams is large. Debris dams in small streams may be formed, moved, or destroyed several times a year, leading to substantial bank erosion (Spencer et al., 1990). Studies of catchments in undisturbed and secondary forests show annual sediment yields between 35 and 312 t/km2/y (Douglas et al., 1992b: 403). These values increase dramatically after clearance or logging.
Forestry and forest clearance by pre-mechanical means, under which large areas in the Peninsula and elsewhere were transformed before the second half of the present century, certainly wrought substantial damage. This is especially so since many areas cleared in the early years were too large to regenerate to forest and were too frequently and heavily worked for cash crops; they became Imperatadominated grassland (Jackson, 1968a). When much of this land was later planted under rubber, clean weeding left the ground bare, with results as discussed in chapter 2. In those upland areas where some timber was selectively extracted, the hauling out of even a small number of logs already entailed soil compaction, the destruction of saplings, and the creation of channels for overland flow.
Tractors, not seriously introduced before the 1960s, were soon followed by much heavier machinery, for the use of which gravelled roads and collection yards were constructed. Crawler tractors then made it possible to extract timber from slopes up to 20° and, with high-lead winching, timber could be obtained from slopes up to as much as 45°. Most timber has, however, continued to be skidded out to roads for transport. Large-scale land clearance and road construction employ bulldozers. The consequences of the use of heavy machinery and skidding logs include soil compaction, loss of topsoil, destruction of soil structure, major reduction of percolation, and exposure to erosion. Roads additionally impede drainage and become pathways for overland flow in which gullies form once constant maintenance has ceased. Following total clearance, it has only latterly become the practice to pile debris along the contour. These effects have been described by many writers (e.g. Burgess, 1971, 1973; Abdulhadi, Kartawinata, and Sukardjo, 1981; Mohd Nor Zakaria et al., 1985).
Criticisms of logging activities within the forest have also emphasized the impact on surrounding trees of mechanized selective cutting, with an average of 50 per cent of the stand being destroyed or damaged although only 30 per cent may be removed (Hamzah, 1978;
Kartawinata, 1978). The compaction of soils impedes regeneration of dipterocarps and favours nomad species, reducing the recovery of desirable timber types for later extraction (Kartawinata, 1990; Whitmore, 1991). Thang (1990) has argued for Malaysia that a second cut in as little as 35 years will be possible only if residual damage is not greater than 30 per cent. One study in a district of East Kalimantan has noted that the proportional areas of "primary" and "secondary" forest have shifted dramatically toward the latter (Sukardjo, 1990).
The construction of roads, the exposure of bare ground, and compaction of the soil all have major consequences for erodibility. In a comparative study of unlogged and logged catchments in Sabah, Douglas et al. (1992a, 1992b) show how a first major increase in suspended sediment discharge followed the construction of a road in the logged catchment. Activity close to the road then led to a dramatic rise, while subsequent extraction on the remainder of the catchment caused an 18-fold excess in sedimentation above levels recorded in the unlogged area a short distance away. A build-up of fine material in the stream-bed suggested, moreover, that "in some storms, more sediment was available for transport than stream energy to carry it" (Douglas, 1992b: 401). Coincidentally, the same 18-fold increase in soil loss after logging was measured using simpler means by Kellman (1969) in Mindanao, the Philippines. Zulkifli, Anhar, and Bahruddin (1990) report a 20-fold increase in a catchment on the Peninsula, and a 60-fold increase over baseline levels, in terms of suspended solids alone, downstream of a deforested area in Sabah. In general, the suspended solids yields of Sabah rivers below timber-working areas are an order of magnitude larger than on Peninsular rivers, yielding calculated erosion rates comparable with that of the notorious Citarum River in west Java (Murtedza Mohamed and Ti Teow Chuan, 1991).
As Macaranga and other fast-growing species colonized the loggedover land in the Sabah catchment, sediment yield fell in a year to 3.6 times the level in the unlogged catchment. However, two years after logging, "the system appeared to be well short of recovery" (Douglas et al., 1992b: 405). Reasons include the effect of soil compaction in greatly increasing overland flow, the presence of ephemeral channels created during logging, and the large quantity of sediment lodged in and along the stream-bed between storms, ready to be moved by the next storm with substantial bank erosion. Because of this enhanced capacity to produce sediment load, which is easily moved in lighter rainfalls, the contribution of the biggest rain events to total annual transport is less than in the unlogged catchment, where 14 days of heavy rain carried 65 per cent of all that was moved during a sevenmonth period in 1988 (Douglas et al., 1992b).
Research does not yet indicate the recovery time of the soil and hydrological system in disturbed forests, but clearly the creation of new channels and heavy soil compaction are enduring changes. Soil compaction under heavy machinery differentiates change in the modern period from what went before; it may therefore be that partial stabilization in areas cleared before the 1960s is not a wholly useful analogy. Nor are there many hard data on the downstream movement of sediment from the converted and logging areas. Many rivers, especially in Borneo, now flow opaquely turbid at all times, reportedly much more so than in former years, indicating fairly rapid transmission of the finer clay and silt fractions. The coarser material, however, is significantly moved only in flood, raises river beds, and forms shoals and bars where channels have been widened; boatnavigation difficulties are reported on some rivers in periods of low flow (Aten Suwandi, n.d.). It is unknown how far the intensive dredging required for ship access at the tidal outlets of some large rivers is due to sedimentation from the land or from the sea. However, data from Sabah indicate serious water supply problems owing to blocking of intakes, and also obstruction of barge traffic in one estuary (Murtedza Mohamed, 1990).
The raising of river-beds, coupled with more rapid runoff after heavy rain, is, however, more than likely to be responsible for the scale of flooding experienced along the lower courses of many rivers in recent years. In formerly forested areas now under rubber and other agriculture, the proportion of annual rainfall becoming runoff is increased from 40-50 to above 60 per cent (Aiken et al., 1982: 188).2 It is significant that, in the western Peninsula, the floods of 1971 were higher than the great "red flood" of 1926 (Winstedt, 1927), although, on the basis of data sets that are not strictly comparable, there may have been less rainfall. However, while there are numerous accounts of flooding assertively attributed to land clearance or forest degradation in the region (e.g. Collins, Sayer, and Whitmore, 1991: 153), it has to be recalled that the proximate cause is always the intensity and duration of heavy rain. Except perhaps in urban areas, data are seldom sufficient to assign, with total certainty, more than a necessary underlying role to human interference.
We can, however, be more certain about the downstream consequences of greater unevenness in hydrological regimes. This irregu rarity leads to a higher incidence of flash floods after heavy rainstorms (Jamaluddin, 1988). There is also loss of soil moisture in valley soils, and of water at irrigation intakes, during even short periods of drought. Enquiries among farmers in valleys below areas recently cleared or logged in the western Peninsula suggested that irregularity of hydrological regime is an important reason for widespread recent abandonment of wet-rice cultivation (Brookfield, Samad Hadi, and Zaharah Mahmud, 1991: 57). It has been stated by the Ministry of Agriculture that, in the Peninsula as a whole, a large part of the 91,203 ha of irrigated rice land lying idle is in this condition owing to lack of water (New Straits Times, 4 January 1991); farmers are being encouraged to shift to dry crops.
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