Introduction to Danau Sentarum National Park, West Kalimantan, Indonesia. (Research Notes).
The Danau Sentarum National Park (further referred to as DSNP or the Park) covers an area of 132,000 hectares, and is located in the floodplain of the upper Kapuas River in West Kalimantan, Indonesian Borneo (Figure 1). The Park lies between the Kapuas River and the border with Sarawak, and is located between 0[degrees]40'-0[degrees]55' N and 112[degrees]00'-112[degrees]25' E at an average elevation of 35 meters. DSNP consists of a series of interconnected seasonal lakes (=danau), interspersed with swamp forest, peat swamp forest, and dry lowland forest on isolated hills. The area was first gazetted as a Suaka Margasatwa (Wildlife Reserve) in 1982 by decree SK No. 757/Kpts/Um/10/l982, when it extended over 80,000 hectares, with just under one-third consisting of open water. In 1994 it was enlarged to 132,000 hectares to include extensive tracts of peat swamp forest, and several hill ranges with dry lowland- and heath forest (Figure 2). In April 1994, Danau Sentarum was declared Indonesia's second Ramsar Wetla nd of International Importance, thus drawing international attention to this unique area. On 4 February 1999, its status was upgraded to that of Tam an Nasional (i.e. National Park) by decree SK 34/Kpts-II/1999, and includes the 132,000-hectare core area, along with a 65,000-hectare buffer zone proposed in 1997. The latter is disputed and has been partly earmarked for oil palm estate development (see Wadley et al., 2000).
DSNP is a key conservation area on Borneo, supporting about 250 fish species (including 12-26 endemics), about 250 bird species, Borneo's largest inland population of proboscis monkey, one of the largest remaining populations of orangutan, possibly three crocodile species, and several dozen endemic plants. The lakes support a large traditional fishing industry, utilized by over 6,500 fisher folk inhabiting 39 villages in and adjacent the Park. Forests are heavily utilized as well, both for construction timber and for a wide variety of non-timber forest products.
Apart from limited input to fisheries management by Dutch colonial administration in the early 20th century (Wadley, 2000a) and by the Fisheries Department since the late 1940s, management of DSNP's natural resources has largely been based on customary law. Officially, DSNP is managed by the Directorate General of Nature Protection and Conservation (Ditjen Pelestarian Konservasi Alam or PKA; formerly PHPA) of the Ministry of Forest and Estate Crops (MOFEC). There was no active management or representation by PKA in Danau Sentarum until the UK-Indonesia Tropical Forest Management Project (UK-ITFMP), which was funded by the British Overseas Development Administration (now Department for International Development) from 1992-1997. UK-ITFMP aimed at (re-)establishing community-based management practices and was successful in some areas, such as reinforcing local customary law, strengthening legislation, and creating local appreciation of conservation values.
PHYSICAL AND BIOLOGICAL SETTING
Hydrology and water quality
Annual rainfall in the Park fluctuates around 3,900 mm per year, while the surrounding hills and mountainous catchment area receive 4,500-6,000 mm per year. The upper Kapuas basin is very flat, and waters of the Kapuas River accumulate upstream of the natural "bottleneck" near Semitau, just downstream of the Park. Because of high precipitation levels, most of the low-lying areas in the basin are flooded in the wetter months. Three-quarters of the lakes in the 6,500 square kilometer upper Kapuas basin are included within the Park. These lakes act as a buffer for the Kapuas River system, mitigating floods and buffering water levels in the dry season. According to a model developed by Klepper (1994), one quarter of peak floods of the upper Kapuas River are siphoned off into DSNP's fakes and swamp forests, thereby significantly reducing flood damage downstream. During the dry season, up to 50 percent of upper Kapuas River waters may consist of water flowing from the lakes and swamp forests, thereby maintaining wa ter levels and safeguarding downstream water supplies.
DSNP is dominated by a marked fluctuation in water levels of the lakes and streams, which may rise and fall up to 12 meters during an average year. During about nine months of the year the lake system is relatively full (average maximum depth 6.5 m), though levels may fluctuate substantially. During the remainder of the year (usually late June-early September), waters usually retreat to the deepest channels and the lakes often dry out entirely. On average this occurs in about two out of every three years. Water enters the system via various streams and inlets, but the main out flowing stream is the Tawang River, which reverses its flow after peak floods. This annual cycle of rising and falling water levels dominates the ecosystem and exerts a strong influence on the lives of its people, plants and animals (Figures 3 and 4).
Because of peat deposits in and around the lake system, the waters of the lakes and streams are colored by tannins, very nutrient-deficient and acidic (pH 4.5-5.5). Light penetration in water is about one meter, while conductivity averages at 16 [micro]S (range 9-24 [micro]S). Dissolved oxygen levels are fairly low, averaging at 4.4 mg/l, while surface temperatures are high (30.4[degrees]C). Suspended matter consists mainly of clay and organic matter, and usually ranges from 10-15 mg/l.
Geology, geomorphology, and soils
The geology is relatively simple, as the Danau Sentarum area consists largely of recent deposits, together with outcroppings of arkosic sandstone (Molengraaff, 1901; Giesen, 1987). Recent deposits mainly consist of illite and kaolin clays in the lake basin, with pockets of shallow to moderately deep topogenous peat occurring at the base of hills and in depressions between levees. Nodules of goethite (bog iron ore) are common throughout the lake basin, and beds of this ore are exposed during the dry season. Soils on slopes consist of highly weathered and nutrient poor loams and sands, with traces of goethite and gibbsite, while those on the flat ridge tops consist of fine to moderately fine sands and loamy sands. In general, soils throughout the area have a low to very low nutrient status and are infertile. The flat topography is relieved by several isolated hills in the Park, that rise from 120-370 meters above the lakes, and hill ranges to the west, northeast and east of the lake basin that rise to about 500 (-700) meters.
Flora and habitats
More than 500 plant species have been recorded at DSNP, belonging to 99 families (Giesen, 2000). Of these, 262 species occur in the swamp forests, three-quarters of which are trees and shrubs. Aquatic herbaceous species are uncommon, probably because of the significant annual fluctuations in water levels, and are generally limited to more permanent bodies of water near the Kapuas River. The flora includes 30-43 species endemic to the DSNP area, and during recent surveys, eight species new to science were discovered (Giesen, 1996, 2000).
Characteristic for DSNP are the swamp forests and lakes, which respectively account for 48.75 percent and 23 percent of the Park. Three major types of swamp forest can be identified: tall, stunted and dwarf swamp forest, which have an average canopy height of 22-30, 8-15(-22) and 5-8 meters, respectively (Giesen, 1996, 2000). Dwarf swamp forest develops in deeply flooded areas, and may be flooded with 4-5.5 meters of water for 8-12 months per year. Tall swamp forest is flooded for 2-3 months annually by 1-2.5 meters of water, and some areas are characterized by peat soils of 0.5-4 meters depth. Stunted swamp forest is intermediate between tall- and dwarf swamp forest in terms of flooding depth and duration. Almost two-thirds of the swamp forest consists of stunted swamp forest, while one third consists of tall swamp forest. Dwarf swamp forest forms a minor element, accounting for 4.8 percent of all swamp forest. Swamp forests are prone to fires, possibly due to the accumulation of large amounts of organic mat ter in the wet months, and repeated fires appear to be leading to an expansion of dwarf and stunted swamp forest, at the expense of tall swamp forest. Most fires are caused by human interventions, and a marked increase can be noted since 1990 (Dennis et al., 2000). Recently burnt areas and swamp forest regenerating after fires together account for a very significant 17.66 percent of the Park (Dennis et al., 2000). Heath forests, which extend over 0.2 percent of the Park, are characterized by uniform, fairly small statured trees (average up to 20-25 meters), and usually occur on very poor, leached sandy soils on the tops of sandstone ridges. Lowland forest is found on the low hills and ridges around the lake basin, and consists of tall to very tall tree, with emergents attaining 35-45(-55) meters.
The lakes of Danau Sentarum are remarkable for their fish diversity, and 240-266 fish species have been identified at the Park and in smaller streams around the area since 1992 (Kottelat, 1995; Widjanarti, 1996; Jeanes and Meijaard, 2000a), including 12-26 new to science. As the lakes measure only 25,000 hectares, this diversity is remarkable when compared to Europe, where a total of only 195 primary freshwater fish are known. In fact, Danau Sentarum harbors one of the world's most diverse fish fauna's of any floodplain lake system: of the 71 tropical and temperate lakes listed for their biodiversity by WCMC (1992), Danau Sentarum (which is not listed) is surpassed only by Lake Tanganyika and Lake Malawi. In the Indonesian context Danau Sentarum is also very rich. Kalimantan, with 394 species (including 340 primary freshwater species), has the richest fish fauna of all Indonesian islands (Kottelat et al., 1993). Of these Kalimantan species, 310 have been recorded in the Kapuas River, which is Indonesia's spec ies-richest. The DSNP fish fauna includes two highly popular aquarium fish: the rare and valuable red variety of the endangered Asian Arowana Scleropages formosus or siluk (listed on Appendix I of CITES), and the Clown Loach Botia macracanthus or ulanguli. The latter is only known from Danau Sentarum and several locations in Jambi, Sumatra. The Park also harbors many interesting species from families that are primarily marine, such as soles, stingrays and pufferfish.
Reptiles and amphibians
Three species of crocodile occur at DSNP, including the rare and endangered False Gavial (Tomistoma schlegeli), the Estuarine Crocodile (Crocodylus porosus), and a third as yet unidentified species (Frazier, 1994, 2000; Jeanes and Meijaard, 2000a). These are listed on Appendix I of CITES, and the first two are also protected by Indonesian law.
Reptiles further include 11 species of turtle and tortoise (Walter, 1996, 2000; Jeanes and Meijaard, 2000a), two species of Monitor Lizard, and numerous snakes. Amphibians are rare in the Park, and the only species found throughout is the River Toad Bufo asper, with more species being found in permanent waters near the Kapuas River.
DSNP's avifauna has been relatively well studied, and has been found to include 237 confirmed and 45 unconfirmed species belonging to 52 families (van Balen and Jensen, 1994; van Balen, 1996; Jeanes and Meijaard, 2000a; van Balen and Dennis, 2000), which is half of the species recorded on Borneo to date (MacKinnon and Phillips, 1993). These include 9 threatened and 22 near-threatened species, including the Argus Pheasant Argusianus argus and the Storm's Stork Ciconia episcopus stormi (van Balen and Dennis, 2000). The Argus Pheasant, which is listed on Appendix II of CITES, occurs mainly in the hills to the southeast of the Park, where it can regularly be heard. Storm's Stork is listed as extremely rare (Silvius and Verheugt, 1989), and may be considered the world's rarest stork (pers. comm. Silvius, 1994). The vast majority of bird species are forest-dwellers, and waterfowl are relatively rare, probably because of a lack of herbaceous aquatic vegetation cover. Colonial water birds such as egrets and herons ha ve been wiped out due to hunting and egg collecting, and the area has probably never had many ducks or waders.
Apart from studies of the Orangutan Pongo pygmaeus (Russon et al., 1996; Meijaard et al., 1996; Russon et al., 2000) and the Bornean endemic Proboscis Monkey Nasalis larvatus (Sebastian, 1993, 1994, 2000; Wood, 1995), DSNP's mammal population has been poorly studied. 55 species have been directly observed in the Park, and a further 88 species have been recorded from secondary, anecdotal sources (Jeanes and Meijaard, 2000a), bringing the total to 143 species. This includes 16 threatened species and 26 species endemic to Borneo. DSNP has the largest inland population of Proboscis Monkeys, but they are elusive, probably due to past hunting pressures, and unlike other populations of this species, they venture far from waterways frequented by fisher folk (Sebastian, 2000). A remarkable recent discovery is that the swamp forests and peat swamp forests around Danau Sentarum harbor what may be one of Borneo's largest populations of Orangutan (Meijaard 1997; Russon et al., 2000).
Habitats similar to DSNP formerly occurred in East Kalimantan, along the Mahakam River, but this area was already heavily disturbed early this century (Endert, 1927; Giesen, 2000), and is now virtually devoid of primary habitat. On Sumatra, similar lake systems used to occur along the Siak Kecil River in Riau Province, but these forests have been logged and burnt and are now severely degraded (Giesen and van Balen, 1991). The largest floodplain lake system in Asia, Lake Tonle Sap in Cambodia, is an order of magnitude larger than Danau Sentarum and used to harbor similar flooded forests. However, centuries of intensive use by Khmer fisher folk have greatly impoverished the area (Giesen, 1998), and Danau Sentarum is superbly rich by contrast. Habitat-wise, DSNP can therefore be regarded as unique. At a species level, DSNP also has a high level of uniqueness, with in the range of 30-43 plants, 12-26 fish species and perhaps one endemic reptile unique to the area (Giesen, 2000; Jeanes and Meijaard, 2000a).
PEOPLE AND EXPLOITATION OF NATURAL RESOURCES
Although located in a remote part of Borneo, the DSNP area has a long history of human settlement and exploitation (Wadley, 2000b; Colfer et al., 2000). Up to about 200 years ago, the area was inhabited by various ethnic groups (later collectively known as 'Dayak'), who cultivated hill rice using swidden practices, and supplemented their diet largely by means of hunting and gathering forest produce. Fishing was also a very important part of the local economy, especially in the Kapuas lakes region (Wadley, pers. comm.). These people had strong animist beliefs that were closely associated with the forests and its wildlife. Islamic Malay culture spread from the Malacca Straits area, Sumatra and Malaya to the coastal parts of West Kalimantan at least 300-400 years ago, and by the late 18th century, it had spread up to the large towns along the Kapuas River, in the vicinity of what is now the Park. The Dayak were generally not displaced, but in the period 1800-1860 many were converted to Islam and assimilated into the Malay culture. The Malay language spoken nowadays in the Upper Kapuas region owes as much to local Dayak languages (e.g. Embaloh and the various Iban groups) as it does to more traditional coastal Malay (Wadley, pers. comm.). Apart from language and religious practices, changes that occurred include the moving of villages from forested areas, where the Dayak traditionally inhabited long-houses, to single family dwellings in villages located along rivers and lake shores. Compared to Malays along the Borneo coast and in Malaysia, however, the Malays in the DSNP area still maintain strong links with the forests, as they still harvest timber and minor forest products, and practice some form of shifting cultivation. Currently, there are 39 villages located in or immediately adjacent the Park, having a total of about 6,500 inhabitants, of which about 85 percent is Malay (Aglionby, 1997). The population density of the DSNP area is about five persons per square kilometer.
The DSNP area is largely inhabited by Malays, which inhabit 34 of the 39 villages located in or immediately adjacent the Park (Colfer et al., 2000). Their total population numbered about 4,000 in 1990, and is currently expected to be about 5,500. During the fishing season (usually June-August) this swells temporarily by about 20 percent, as relatives from the Kapuas River towns may join them for several months. About six of these villages are temporary fishing camps, but the majority is permanent, and several of the largest villages boast mosques, schools, primary health centers and police stations (Figure 5). While some villages have been established during the last two decades, many have a much longer history, and some are several hundred years old (Giesen, 1987; Wadley, 2000b). All Malay villages maintain strong ties with larger Malay towns located along the Kapuas River, and the sub-district boundaries follow the old Malay fiefdom boundaries established by the colonial administration in 1880 (Wadley, n.d. ). During religious festivities or censuses, for example, Malay villages in the Park are largely deserted, as most inhabitants move back to their ancestral town along the Kapuas River to join relatives. In order to cope with the rise and fall of water levels, houses are generally built on poles or float on rafts of timber.
The Malay economy revolves entirely around fishing, which is the major source of protein and provides most of the Malay family income (Golfer et al., 2000). When water levels are high, fishing activity is at ebb and carried out for subsistence only. During the onset of the dry season (usually June), as water levels drop, fishing activity picks up, and when the lakes have almost dried out, fishing activity peaks and almost everyone is involved. Fishing practices include the use of a wide range of cast nets, gill nets, fixed nets, funnel nets, lift nets, traps, barriers, hooks-and-lines, and even excavated pits (Giesen, 1987; Dudley, 2000). Most fish are sun-dried and salted, as the remote location excludes the possibility of marketing fresh fish, with the exception of several high-value species. The latter include ornamentals, such as the Clown Loach and the Asian Arowana, but also highly prized food fish such as the Marbled Goby Oxyeleotris marmorata or ikan lemas, Sultan Fish Leptobarbus hoevenii or jelawat, Featherback Chitala lopis or belida and Giant Snakehead Channa micropeltes or toman. The latter three also form the basis for floating cage culture, whereby fish are fattened in captivity before being shipped to market. Certain catfish are processed as smoked fish, and these are mainly Kryptopterus apogon, known locally as lair bemban. Other fish products include fermented fish or buduk, fish crackers or krupuk (for which mainly C. lopis is used), and fish eggs (mainly of Kissing Gouramy, Helostoma temminckii or biawan) (Giesen, 1987; Dudley, 2000). The estimated total annual catch ranges from 7,800-13,000 tons, which is about 97.5-162.5 kg/ha, which is similar to that of the Mahakam Lakes in East Kalimantan (139 kg/ha, Dunn and Otte, 1983) and that of Lake Tonle Sap in Cambodia (147 kg/ha, van Zalinge and Touch, 1996). Each village has a head fisherman or ketua nelayan, who presides over fishing activities and assures that proper practices are adhered to in the villages' fishing area. Certain techniques are prohibited, such as the use of fixed bag nets (jermal) in certain areas, the use of fish poisons, and--strangely enough--the use of earthworms as bait.
The fishing industry is a valuable one. A large (50-60cm), reddish-golden colored Asian Arowana can sell for as much as several hundred US dollars in the lake area, and be worth more than US$1,000 (or even US$ 5,000) by the time it is sold in Jakarta. Marbled Goby, valued locally at about US$10 per kilogram, are shipped live, in oxygenated plastic bags, to markets in Singapore and Japan. Clown Loach are shipped the world over, as they are not bred successfully in captivity. The total value of the market is currently valued at about US$ 2.2 million (Aglionby, 1997), but it should be noted that the Asian Arowana is now very scarce and barely contributes to the local economy.
Rice is the most important staple of the Malay, and most of this is obtained by purchase, as suitable areas in which to cultivate rice are very scarce in the Park area. The Malays practice some swidden or ladang, but this is limited to the upper levees of the main rivers in the basin, and crops other than rice are generally grown, such as cassava, maize, eggplant, cucumbers, beans and chili's (Colfer et al., 2000). About 4,500 hectares have been cleared altogether for ladang, which is about 3.5 percent of the Park.
Honey is an important product at DSNP, and the honey industry dates back to at least the early 1800s (van Lijnden and Groll, 1851; Mulder et al., 2000). The industry is well-described by de Mol (1933), who reported that at that time, about 500 families collected honey and wax in the area, each family operating 40-150 tikung. (1) Harvesting occurred mainly at the end of the wet season, or early dry season, by smoking the bees--migratory Asian Giant Bee Apis dorsata--out by means of a torch. Bees also make use of large boughs of trees, and such a natural honey tree is called lalau--which are also marked and "owned" for a season by the person discovering the combs. The industry had withered somewhat over the past decades due to dwindling honey prices, but has picked up again due to promotion by UK-ITFMP. The total honey yield of the Park was estimated to be 20-25 tons in 1993, with almost one third of all families participating, having 10-500 tikung each (Rouquette, 1995; Mulder et al., 2000). In 1993, the value of the industry was about US$ 7000 locally, but almost ten times this in Pontianak, the provincial capital. In villages where honey is collected in reasonably large amounts, regulations have existed for a long time, and in some villages a person specifically responsible for the honey (the ketua madu or ketua priyau) is appointed (Rouquette, 1995; Mulder et al., 2000).
Malay harvesting of timber
Timber is in high demand in the Malay villages, for a wide range of uses, including housing, boat and canoe (sampan) construction, simple furniture, tikung, walkways, and floating cages. Although a wide range of timber species may be used, including a range of dipterocarp (meranti) species, the most desired timber species is Fagraea fragrans (Loganiaceae), known locally as tembesu, which produces a very durable, high quality timber that is very resistant to rot and termites (Peters, 1994b). Harvesting is restricted to periods of high water, to facilitate transport of the timber, and usually carried out in October-December, in the lull period following the fishing season (Peters, 1993, 1994a, 1994b). As a general rule, the intensity of logging is inversely proportional to the intensity of fishing. Generally, harvesting of timber in the area governed by a particular village (i.e. the wilayah kerja, or utilization area) is controlled by the village head or head fisherman ketua nelayan. Villagers may harvest free ly for themselves, provided that it is for their own use, while permission is granted to outsiders, provided that they follow protocol (i.e. ask permission), and harvest for their own use rather than for commercial purposes.
Malay harvesting of non-timber forest products
Malays harvest a wide variety of non-timber forest products in the Park's swamp forests, and in addition to honey, the most important are three species of rattan (cane): duri antu (Calamus schistoacanthus), duri tapah (Calamus tapa) and duri pelanduk (Ceratolobus hallierianus) (Peters, 1994c; Peters and Giesen, 2000). One person can harvest up to 150 canes on a good day, and from 3,000-5,000 per year, depending on market conditions and the flooding cycle. Locally, rattan is used for tying and bundling, and most importantly, for the construction of fish traps and barriers. Commercially, rattan is usually sold in bundles of 50 canes, sold for about US$ 1.00 (1994 rate). Women and children are generally the most important rattan collectors in a community.
The Malays extract many other products from the swamp forests and lakes of the Park, including many fruit, vegetables, timber, herbal medicines and plant dyes (Table 1). Over the years the inhabitants of the lake area have discovered uses for such a variety of plants, that there are, few species that are not found to be useful in one form or other. Giesen (1987) recorded that, for a total of 207 plant species, 81 percent were put to use by local communities, being either consumed directly as fruit or vegetable (30%), used for construction (27%), medicine (6%) or other household uses such as dyes, rope, weaving, household appliances, glues and insect repellent (18%). Plants used as firewood only totaled a mere three percent, and numerous plants have multiple uses. Malays hunt Sambar Deer Cervus unicolor, but are restricted by religious beliefs from hunting other wildlife.
Dayak inhabiting the DSNP area belong to three ethnic groups: Iban, Embaloh and Kantu'. The Embaloh and Kantu' inhabit the areas east and west of the lakes, respectively, and the Iban mainly occupy the area to the north and northeast. The flat area to the north and northeast of the lakes is called the Emperan, and the Iban in this area call themselves the Emperan Iban (Wadley, 2000b). Currently, there are about 1,200 Dayak in the area, inhabiting 5 of the 39 villages located in/adjacent DSNP (Golfer et al., 2000). The majority of Dayak in the region live in the hills and higher ground that surrounds the Park, and their villages are located well outside DSNP. These people mainly depend on upland rice based on shifting cultivation, in combination with hunting and harvesting of forest products. Fruit trees are cultivated in and around the communities, and rubber plantations may also be established, often at some distance from the village. Forests within the utilization area of a given village may be veritable fo rest gardens, and following centuries of enrichment planting, certain patches of forest are particularly endowed with desirable species, such as tengkawang. (2) The Dayak agroforestry system practiced on the periphery of DSNP has resulted in a mosaic of habitats, consisting of shifting cultivation patches (often in various stages of regrowth) and patches of forest preserved for various purposes. The latter may be preserved for religious purposes, an abundance of honey trees, unfavorable soils conditions (e.g. many boulders), or an abundance of fruit trees (Wadley, 1999).
Dayak villages vary from small longhouses, housing up to 5-8 families, to large longhouses (15-30 families; Figure 6) and market towns such as Lanjak, where families have individual houses. Iban Dayak have been engaged in migrant labor for a long time (Wadley, 2000a), and many young men spend several years working in nearby Sarawak, usually in the logging industry or on plantations. When there are few opportunities for cash income at home, adult male absence due to labor migration may be 50 percent or more in most longhouses. Villages have become quite dependent on the supplementary income provided by this migrant labor, no so much for subsistence, as for schooling and consumer goods (Wadley, 2000a).
Dayak villages located within the Park are actively involved in fishing, although they are more oriented towards dryland activities such as shifting cultivation and hunting than their Malay neighbors (Golfer et al., 2000). Iban Dayak hunt a variety of wildlife within and near the Park, including turtles and tortoises, Reticulated Python Python reticulatus, Bearded Pig Sus barbatus, Sambar Deer, Malayan Sun Bear Helarctos malayanus, Orangutan, and numerous bird species. Turtles and tortoises are generally hunted in the dry season, and a large proportion of the catch--an estimated 50 tons--is traded live in Sarawak (Walter, 1996; Walter, 2000). Crocodiles--especially Crocodylus porosus--were formerly hunted as well, but populations are now so low that they are rarely hunted nowadays. Nests of the Edible-nest Swiftlet Collocalia fuciphaga and Black-nest Swiftlet Collocalia maxima are harvested from a number of caves located in the sandstone ridges in the southeastern part of the Park. These are marketed in Chine se communities in West Kalimantan and in Sarawak.
ECONOMIC BENEFITS DERIVED FROM DSNP
Many of the benefits derived from the DSNP cannot be directly expressed in monetary terms. The lake basin plays several very important functions, such as buffering Kapuas River waters (flood prevention, maintenance of river transport and water supplies), and providing a habitat for many species of fish, reptiles and other wildlife. The lakes of the Park have a strong effect on the flow of the Kapuas River. In the dry season, up to 50 percent of upper Kapuas River discharge may consist of lake water, while in the wet season, up to 25 percent of peak flow is absorbed by the lakes (Klepper, 1994). Also, most of the extracted resources are for local subsistence, and do not enter the market economy. Extracted resources that do enter the market economy were valued at about US$ 2.6 million in 1996, while direct (unmarketed) domestic benefits were estimated to be about US$ 16 million (Table 2, Aglionby, 1997).
CHALLENGES TO MANAGEMENT OF NATURAL RESOURCES
Exploitation levels appear to have been sustainable until about 2-3 decades ago; since then, however, the resource base appears to have been steadily eroding, with fish catches declining and forest area dwindling (see also Wadley et al., 2000). The main reasons for this are complex, involving an influx of immigrants, increased non-adherence to local customary law, population increase, increased access to external markets, and a steady development of adjacent areas (e.g. by large-scale logging enterprises and plantation enterprises). Interviews with the leaders of 30 villages indicate that 90-93 percent find that fish, honey and wood resources have declined over the past decades, while 80 percent find that rattan resources have declined (Aglionby, 1997). This is of course highly subjective, but the trends are supported by other data.
Because of the large year-to-year variation in fish catches, it is difficult to assess with certainty that the overall trend of the resource is one of decline. Official fisheries data are unreliable, and with numbers of fisher folk also increasing, subjective individual accounts are also not reliable. However, 17 commonly caught fish species are possibly over-fished, as is indicated by average size of specimens caught, compared to maximum size attainable for each species (Dudley, 2000). Certain species have certainly been over-fished, as they were formerly fairly common, but now have virtually disappeared, in spite of general environmental conditions in the Park remaining favorable. The latter include the Asian Arowana, and a number of cyprinids, such as the Sultan Fish, Freshwater Dorab (belantau, Macrochirichthys macrochirus), and tern unit Labeo chrysophekadion.
Remote sensing data show that about 25 percent of the Park's swamp forests have been burnt over the past decades (Dennis et al., 2000), of which about half had burnt since about 1990. DSNP has a long history of burning, dating back at least to the mid-19th century and possibly for more than 1,000 years (Dennis et al., 2000), but remote sensing imagery indicates that burning is becoming more frequent and widespread, especially since 1990. Following burning, biodiversity is lost, as the regenerating forests are lower in stature and have a much lower species diversity than the original swamp forest (van Balen and Jensen, 1994; Giesen, 1996; Giesen, 2000).
Studies by Peters (1994b) on the Fagraea fragrans (tembesu) resources of DSNP indicate that wood resources are becoming depleted. Woodcutters complain that large tembesu trees are becoming more difficult to locate, and that they have to travel further and further into the forest to locate a merchantable stem. The number of people in the Park that own chainsaws appears to be decreasing. In Nanga Kenelang village, 20 persons had a chainsaw in 1983, and by 1993 this had declined to 11. Transects in the swamp forests show that 80 percent of desirable trees with >40cm dbh have already been cut, and those that remain are of poor quality (e.g. hollow stem). There is little sign of regeneration, and large trees (>60cm dhb) currently being sought are probably >200 years old, while a 40cm dbh tree may be 50-60 years old (Peters, 1994b).
Crocodiles were once abundant in the DSNP, as is graphically described by Beccari's (1904) account of his 1867 visit to the area, whereby he lost several of his travel companions. In the mid-1980s there were still some traders in crocodile skins located in the towns along the Kapuas River, and these received most of their stock from the lakes (Giesen, 1987; Frazier, 1994, 2000). By the early 1990s this trade had died out, partly due to the decline on the world market, but also due to dwindling numbers in the wild. A survey by Frazier in 1994 concluded that crocodile numbers are low, and conditions for crocodile population viability within and around the Park are sub-optimal. The latter is mainly due to the high degree of human disturbance and activity-threats to crocodile populations that have existed for some time (Frazier, 2000).
Colonial water birds were formally common in the Park, as is evident from local names for certain locations (e.g. birds-nest lake, bird-island lake, bird-breeding lake), accounts from old residents, and Beccari's (1904) account of large numbers of white water birds (probably egrets). Probably the clearest evidence comes from Enthoven's (1903) report of water bird colonies "with many nests in the tops of almost submerged trees and shrubs." He goes on to describe "if water levels are low when eggs are laid, the Batang Loepars <Iban Dayak> eagerly collect these eggs, which are considered a great delicacy and ideal for garnishing a dull platter of rice." Older residents report that formerly hundreds of birds used to converge in colonies but that egg collecting had decimated their numbers (Giesen, 1987). Nowadays, colonial water birds such as egrets, herons, night-herons and bitterns still occur in small numbers, but apart from Purple Heron Ardea purpurea, none breed in conspicuous colonies (van Balen and Dennis, 2000).
CAUSES OF DWINDLING RESOURCES
Population increase and poverty
The population of the DSNP area appears to have grown by almost 40% in the period 1985-1995 (Aglionby, 1995), which according to Wickham (1997) is increasingly forcing people to unsustainably and/or illegally harvest resources to meet their daily subsistence needs. Annually, there appears to be a bottleneck in the income of the Malay population in the Park area (Aglionby, 1995; Wickham, 1997), with a strong decline in income at the end of the fishing season (September-October). To counter this decline in income, additional sources of income are sought, such as timber and non-timber forest products. In years during which water levels do not drop considerably in the dry season, the fishing season is poor and this leads to a significant drop in fish-derived incomes. As a result, the impact on non-fish resources of the Park becomes more pronounced and may lead to conflicts between communities (Wickham, 1997). Low income levels prevent families planning resource utilization with a long-term outlook, and in DSNP th e main staple-rice--has to be purchased with receipts from other resources. The average annual per capita income in the area is US$ 265 (1996 figures), which covers basic subsistence requirements (US$ 221), but leaves only US$ 44 for all other needs (Aglionby, 1997). However, even this meager level of income appears to be maintained through unsustainable resource use.
Undefined access rights
From 1982-1999, when DSNP's status was that of wildlife reserve, the people living in the area were deemed "illegal residents" according to national law. Most of the communities were totally unaware of this because they have had usufruct rights for hundreds of years, and had settled in the area long before it was gazetted. With the change in status in 1999 to that of National Park, this problem has disappeared, as a National Park may incorporate various forms of resource use and habitation. The local community believes they have full usufruct rights based on their historical rights, when the area was divided into different sultanates that included the current Park area, and more recently, when DSNP and the surrounding area was divided into utilization zones (Aglionby, 1997; Wickham, 1997). Each village has its own utilization zone (wilayah kerja), which is managed by a locally elected head fisherman with responsibility to enforce traditional law or hukum adat on resource harvesting. However, hukum adat is los ing its power as communities are influenced from outside, and as government by state replaces that by elders (Aglionby, 1997). Access to the area is difficult to limit, as all waterways in Indonesia are open access, and people from outside may come on a seasonal or incidental basis. Because of traditional ties with the large towns along the Kapuas River, there is a seasonal influx of persons during the peak fishing season, leading to a temporary 20 percent increase in population. Complicating matters even further, local government officials have at times also declared the Park's fisheries resource an open access resource, available to all outsiders, despite local protests.
More efficient harvesting techniques
Due to the introduction of modern technology, more efficient harvesting techniques have been introduced into the area. These include the introduction of mass-produced hooks (at the turn of the century), gill nets (late 1940s-1950s), rifles (1950s-1960s), engine-powered boats (1970s), finer fishing nets (1980s), chainsaws (1980s), and chemical fish poisons (1980s-1990s). Gill nets were introduced after the Second World War, and immediately lead to a great increase in fisheries production (Vaas, 1952). Currently, however, small-meshed gear is commonly used, and Dudley (2000) has assessed that about half the gill nets used have a mesh size of less than two inches. This undoubtedly leads to fish being caught at sub-optimal sizes. The fishing effort has also been increased by the introduction of outboard engines, which increases fishing efficiency and makes remote fishing areas more accessible. Currently, about half of all fishing families have (access to) a small outboard engine (Dudley, 2000). Chainsaws were fir st introduced in the 1970s, and became popular in the 1980s, when commercial logging enterprises were active in the area. By the late 1990s, however, the number of chainsaws appears to be decreasing, and halved again in some villages (Peters, 1994b).
Traditionally, Dayak in and around DSNP carry out stream fishing using a concoction based on the roots of the leguminous climber Derris elliptica, locally known as tuba. During the past few years, however, industrial chemicals (e.g. potassium cyanide) and 4 pesticides (notably the insecticide Thiodan (4)) are also used on occasion because they are cheap and highly effective in stunning and killing fish. However, unlike tuba, which soon becomes less active, use of these chemicals has resulted in large, downstream fish kills. In August 1994, for example, fish were killed along a 30 km-long stretch of river in the central part of the Park, resulting in the demise of fish kept in floating cages, and representing a loss of about US$ 150,000 to the fishing communities (Aglionby, 1997). The use of commercial poisons appears to be largely in the hands of Dayak merchants, who aim at large kills for the purpose of sale (Wadley, pers. comm.).
Development and commercial forestry
The Park is slowly losing the isolation that has long shielded it from some of the adverse aspects of development (Wadley, 1998). In the mid-1980s, slow passenger-cum-cargo boat plying along the Kapuas River, provided the only means of transport along the 200+ kilometer stretch from Sintang to the villages near the DSNP. At that time, a 30 kilometer-long dirt footpath provided the only access to Sarawak, taking the better part of a day to cover. Nowadays, a paved road leads almost the entire way to Semitau, some 30 kilometers from the Park's southern border, and several passenger speedboats pass by daily. Jalan Lintas Utara in the Badau and Lanjak area is largely paved, although not the section between the two, and a dry weather road provides access from Lanjak to Lubuk Antu, in Sarawak, reducing travel time in the dry season to just over an hour. Easier access means that markets are more easily reached. As a result, less produce is lost by spoiling of goods, and higher prices are fetched. Certain live fish p roducts are now being shipped to distant markets, which was once viable for highly valuable species only. At the same time, market demand for certain products increase, and this may lead to an increased pressure on remaining resources.
Deforested slopes to the northeast of DSNP have been earmarked for replanting with oil palm, perhaps in combination with a resettlement scheme. On the one hand, reforestation of these grassy Imperata covered slopes is probably desirable in order to curb erosion. On the other hand, oil palm production notoriously goes hand in hand with a heavy use of pesticides (especially rodenticides) and fertilizers, thereby affecting water quality in local streams and lakes.
Commercial logging companies held concessions in the tall swamp forests on the periphery of the Park, and in the adjacent lowland forests. They have not operated on the steep slopes of the hills and ridges, nor have they been active in the swamp forests of the original 80,000-hectare reserve (Giesen, 1987; 1996). The latter has not been entirely out of respect for conservation ideals of the area, but because the original 80,000 hectare reserve holds little timber of commercial importance. At present, commercial logging activity near the Park is limited, as prime areas have already been selectively logged. However, small-scale logging carried out by locals who sell logs to these companies appears to be on the rise since 1997 (Wadley et al., 2000). Logging companies are active along the Embaloh Leboyan River, and log rafts and barges are transported through the Park, as this is the only point of exit from this river. Logging companies create a demand for temporary unskilled labor, food supplies, and other produ cts (e.g. rattan), but may disrupt local communities because of socially unacceptable behavior (alcohol abuse, prostitution). They affect the Park by their workers introducing and illegally using firearms, and because of the transport of log rafts, which causes physical damage of river-lining forests, and release of insecticides used to cure the logs. Locals with chainsaws also carry out commercial logging, but on a much smaller scale than the aforementioned companies. In 1995 there were 91 chainsaws in the DSNP (Aglionby, 1997), a number that was on the decline (Peters, 1994b).
Apart from occasional lightning strikes, fires are generally caused by human intervention, and may be ignited for a variety of reasons. Some fires are accidental, for example, escaping from cooking fires of persons in the forests (e.g. hunters or honey collectors). Deliberate burning may be carried out to clear an area for shifting cultivation, or to make it easier to set up nets with which to catch fish. It has been suggested that burning is associated with catching Asian Arowana (Luttrell, 1994), as these nocturnal fish are reportedly attracted by lamps, which are better observed unimpeded by dense shrubs and trees. Currently, about one quarter of all swamp forests have been affected by fire, and the steady increase in incidence of fires suggest that it is associated with shifting cultivation and netting, rather than Arowana fishing, as the latter have become exceedingly rare and are seldom fished for nowadays.
Lack of information
Many government officials and local communities do not realize that DSNP is a special place, a unique ecosystem with a unique biodiversity, and one that is officially protected by Indonesian law (Aglionby, 1997). Many are also not aware of fairly simple ecological processes, and government officials and fisheries biologists have at various times proposed damming off the Tawang River, which forms the main outlet of the DSNP lakes. The Department of Public Works proposes that a dam could enhance the natural buffering capacity of the lakes, as water could be released late in the dry season, providing freshwater for coastal towns. The costs would be immense, however, both in terms of financial investment and for the natural ecosystem, as prolonged flooding would lead to forest death, and a subsequent decline in fisheries. Also, transport through the area would no longer be possible, as the Tawang forms the main transport route for people and produce. Fisheries biologists have suggested that maintaining water leve ls (by means of a dam) would prevent the annual dramatic loss of fish numbers, and stabiles fish populations. What they fail to realize is that floodplain fisheries depend on the annual cycle of flood and declining water levels, and that tampering with this cycle usually leads to a severe decline in fisheries.
Management of DSNP's natural resources has largely been based on customary law hukum adat, which recognizes wilayah kerja (utilization areas), which are resource assess areas belonging to each village. Hukum adat is well developed for the most valuable or more threatened resources, such as fisheries, major wildlife, honey and edible bird's nests, but less well developed for other forest resources such as rattan and timber. According to Peters (1994a), this is an indication that these resources have only recently been subject to increased pressures.
After the Second World War the Fisheries Department established a large fisheries center in Selimbau, on the Kapuas River close to the Park. Officers from this center carried out regular fish sampling and maintained a record of fisheries data for a number of key fishing villages. Also, a fishing market was maintained, extension work was carried out, and fish stocking programs were launched. The latter were mainly based on exotics such as Nile Tilapia Oreochromis nioticus and Snake-skin Gouramy Trichogaster pectoralis, both of which fortunately did not thrive in the lake system. In addition, the Fisheries Department also provides licenses for jermal (funnel nets), as a way to limit the number of jermal, while at the same time raise revenue for the department. On the whole, the Fisheries Department has little impact on fisheries management, and their operations in Selimbau appears to be drawing to a close, with buildings on the verge of collapse, and the market already closed down by 1985 (Giesen, 1987).
Officially, DSNP is managed by the Directorate General of Nature Protection and Conservation (Ditjen Pelestarian Konservasi Alam or PKA; formerly PHPA) of the Ministry of Forest and Estate Crops (MOFEC). PHPA are represented in the provinces by the Natural Resources Conservation Units (Konservasi Sumber Daya Alam or KSDA), and the Sub-balai KSDA of West Kalimantan resides under that of West Java. There was no active management or representation by PKA in Danau Sentarum until the UK-Indonesia Tropical Forest Management Project (UK-ITFMP), which ran from 1992-1997 and included a conservation project at Danau Sentarum. This project, commonly referred to as the DSNP Management Project, was implemented by the international NGO Asian Wetland Bureau (now Wetlands International).
Under UK-ITFMP, numerous baseline studies were carried out, along with attempts at establishing community-based management and introducing novel approaches to natural resource management. Park management infrastructure was developed by KSDA and UK-ITEMP, and a reserve management network has been in the area since 1992. UK-ITFMP aimed at (re-)establishing community-based management practices and was successful in some areas, such as reinforcing local customary law, strengthening legislation, and creating local appreciation of conservation values. By means of increasing local "value added," the program was also successful in generating additional local income without significantly increasing pressures on natural resources. Two notable examples are the promotion of the honey industry, which aimed at better quality bottled products, and the rattan industry, whereby the production of rattan products was promoted to replace the sale of raw rattan (Wickham, 1997; Mulder et al., 2000). In spite of this, many challeng es remain, including external threats (immigration, development), incorporating local customary laws into the Forestry Department's modus operandi, and establishing continuity in management approaches (see Wadley et al., 2000).
Table 1 Use of plants at DSNP Type of use Number of plant Percentage * species (n=207) Eaten by wildlife 106 51 Human consumption (fruit, 62 30 vegetable) Construction 56 27 Other (household use, glues, 27 18 rope, weaving, dyes) Medicine 13 6 Firewood only 6 3 No known use 27 13 Adapted from Giesen (1987), who listed 207 plant species in his inventory of DSNP. * More than 100% because one species may have more than one use. Table 2 Monetary benefits derived from extracted resources. Natural Resource Rupiah US $ Lake and river fishing 2,905,800,000 1,285,752 Fish cages 1,800,000,000 796,460 Ornamental fish 505,000,000 223,451 Wood 356,085,000 157,560 Edible swiftlet nests 136,900,000 60,575 Turtles and tortoises 56,000,000 24,779 Rattan 54,800,000 24,248 Honey and beeswax 50,000,000 22,124 (3) TOTAL 5,864,585,000 2,594,949 Adapted from Aglionby (1997)
Most of the studies reported in this volume of the Borneo Research Bulletin have been carried out as part of the UK-Indonesia Tropical Forest Management Project, funded by the British Overseas Development Administration (now Department for International Development). The Danau Sentarum Management Project of UK-ITFMP was implemented by the Indonesia Programme of the Asian Wetland Bureau (now Wetlands International--Asia Pacific), together with PKA and KSDA Sub-balai West Kalimantan. On behalf of all those contributing to this special Danau Sentarum volume of the Borneo Research Bulletin, the authors would like to extend their gratitude to PKA, KSDA, DfID and Wetlands International for allowing us to carry out these studies. We would also like to extend our sincere gratitude to the people of Danau Sentarum, without whom most of these studies would have been impossible.
(1.) Tikung are thick planks made from the tembesu Fagraea fragrans tree, U-shaped in cross-section, 1-1.5 meters long and with a deep notch at each end. They are placed horizontally in target trees, with the convex side down. Tikung are individually owned, and if migratory bees make their nest on one, the honey/wax belongs to the owner of the tikung.
(2.) Tengkawang is a generic term for a number of mast fruiting species of dipterocarp that produce oil-containing nuts that are exploited, and used for instance as a cocoa butter substitute.
(3.) In 1993 this was valued at US$7000; since then, this has increased to US$ 22,000, because of projects aimed at increasing added value.
(4.) Thiodan is the brand name; the active ingredients are Dichlorvos and Bioallethrin.
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