Contributions to Zoology, 73 (4) 283-291 (2004)

SPB Academic Publishing bv, The Hague

habitat disturbance and the biomass of Effects of and hunting on the density the endemic Hose’s leaf monkey Presbytis hosei (Thomas, 1889) (Mammalia:

Primates: Cercopithecidae) in east Borneo

Vincent Nijman

Institutefor Biodiversity and Ecosystem Dynamics, Zoological Museum, University ofAmsterdam, P.O. Box

94766, 1090 GT Amsterdam, The Netherlands, e-mail: [email protected]

Keywords:: colobines, conservation, logging, primates; shifting cultivation

sizes and biomass 286 Abstract Densities, group

Correlations between densities and habitat

parameters 287 Hose’s leaf monkey Presbytis hosei is endemic to Borneo and Discussion 288 decades Borneo has lost a occurs only in tall forest. In recent The effects of habitat disturbance 288 large part ofits forest cover, mostly in low-lying coastal regions. The effects of hunting 289 Large intact tracts offorest remain in the interior, but these are Conservation prospects in interior Borneo 289 by and large inhabited by tribes that subsist in part by hunting. Acknowledgements 290 The combined effects of habitat disturbance and hunting on the References 290 studied in densities and biomass of Hose’s leaf monkey were

Kayan Mentarang National Park in Borneo’s far interior. Over

were collected four months, data on densities and hunting by

transect walks in four forest types. Hose’s leaf monkeys were Introduction

hunted to deter crop-raiding, for their meat, and to obtain bezoar

stones (visceral secretions used in traditionalmedicine). Hose’s The Sundaic region is recognised as one of the most of 7-8 leaf monkeys occurred in single male groups individuals et in densities from 2.3 Densities of Hose’s important global biodiversity hotspots (Myers 0.8 to groups km-2.

ah, and within the the con- leafmonkeys were positively correlatedwith certain vegetation 2000) region largest

and of first bough, and tinuous of rain forest is found characteristics, e.g. tree height height expanse on the is-

the nearest Biomass negatively correlatedwith distance to village. land of Borneo. Until few decades only a ago, the of Hose’s leaf monkeys declined considerably as a result of island was almost completely covered in forest. habitat disturbance and hunting from 92 kg km-2 in primary hill of Borneo’s forest for tim- forest Large-scale exploitation forest inside the reserve to 38 kg k m- 2 in old secondary ber the of the and km-2 in forest A re- began at end 1960’s and 31 kg young secondary near villages. currently 90% view of the few studies conducted on the effects of habitat some of the forest (excluding conservation

Hose’s leaf reveal disturbance and hunting on monkeys areas) in Sarawak is under logging concession trends in and inconsistent biomass density responses. (MacKinnon et al., 1996). The total area of forest

under concession in Indonesian Kalimantan is ac-

tually larger than that of remaining forest (Rijksen Contents and Meijaard, 1999). Every year vast areas are

cleared for agriculture, plantation, human settle- Introduction ‘ 283 and timber In the last few de- Methods 284 ments, production.

284 Borneo Study area and study sites cades has become well known for its large

calculation of 285 Primate censuses and density forest fires that coincide with the El Nino South- Biomass 285 ern Oscillation Event (Siegert et al., 2001). Apart Vegetation sampling 285 from the economic the forest fires damage cause, Analysis 286 the loss of forest has consider- Results 286 over large areas a

in Vegetation 286 able effect on the wildlife. The forests the inte-

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Data rior of Borneo have suffered significantly less from as Deficient on the Red List of Threatened

the fires than the low-lying, more coastal, parts. Species (IUCN, 2003).

This be in the low human may explained part by

population density (less chance of ignition), less

selective logging (which greatly increases the risk Methods

of of fire), and a shorter dry season (as a result

and orographic rainfall caused by mountain ranges). Study area study sites

number The interior is home to a large of tribes

known The in Data collectively as Dayak. Dayak live were collected during September-December

villages and practice shifting cultivation. In addi- 1996 in and around the Kayan Mentarang National

the interior is the home the East Indonesia. The is tion, to Punan, a group Park, Kalimantan, park one

hunt- of Southeast and of formerly nomadic tribes that subsisted by Asia’s largest reserves with adja-

ing and gathering. In contrast to the largely Islamic cent (proposed) reserves it covers an area over 2500

km 2 and is the home of Malayans that inhabit the low-lying coastal areas, approximately 10,000 people.

they arc skilful hunters. Although the Punan and The study sites were in the Nggeng Bio, Bua Alat

Dayak occur at low population densities, there are and Tebulo river valleys, in Kayan Mentarang’s

few restrictions on the species that can be hunted Bahau region [115°50’E, 2°50’N], The valleys lie

and the of select of between hills that are intersected impact hunting on a group species steep by many

might be considerable, even leading to (local) ex- small streams. The study sites are at an altitude of

300-800 500 tinction (Sumatran rhino Dicerorhinus sumatrensis: c. m asl but are mostly below m asl.

sites situated close Rookmaaker, 1977; orang-utan Pongo pygmeus : Forest were together (<10 km)

Rijksen and Meijaard, 1999; proboscis monkey and were similar with regards to climate, original

forest altitude and The is Nasalis larvatus: Meijaard and Nijman, 2000a). type, topography. area

virtue make covered in lowland with hill By of their wide appeal, primates may dipterocarp rainforest,

ideal flagship species for tropical ecosystem con- dipterocarp rainforest to submontane forest in the

servation. Borneo is rich in primates with 13 spe- higher parts. True riverine terrace forest is rare or

cies, of which nine are endemics (Meijaard and even absent. Secondary forest of different ages is

Nijman 2003). Most of the endemics and both glo- found along the banks of the Bahau River and in

bally threatened species (orang-utan and proboscis the vicinity of the villages, but is usually not found

monkey) are vulnerable to the loss of their forest beyond the first mountain ridge from a village.

Mature habitat, and site protection is widely seen as the forest is still found close to the major riv-

mechanism their conservation. The effects between key in ers, on steep slopes, and halfway villages.

of hunting on primates in Borneo are poorly known The Nggeng Bio river valley has been a ‘tana

(Nijman, 2001). ulen’ (restricted forest) of the nearby village of Long

In this, I report on the effects of hunting aVid Alango for more than 75 years, and is covered with

habitat disturbance on the abundanceof Hose’s leaf tall primary forest. Most of the Bua Alat river val-

monkey Presbytis hosei in the Bahau region, East ley is covered in primary dipterocarp rainforest.

Kalimantan. This species is restricted to north Near the mouth of the river, however, it is replaced

Borneo: the States of Sarawak old forest that last 45 Malaysian (north- by secondary was logged years

ernmost and the Brunei in The part) Sabah, Sultanate, and ago, 1951. mouth ofthe Tebulo river valley

the northern half of the Indonesian province of East comprised mainly cultivated land, including the

of Kalimantan. It is one the few species of Presbytis village of Long Tebulo. Throughout the valley a

leaf that have been monkeys not studied in any detail patchwork of regenerating forest is present, rang-

20 (but see Rodman, 1978; Mitchell, 1994) although ing from one to years of age. The study was

been in it has included a number of wildlife conductedin forest between 10and 20 sur- patches years

data is available on the of of which with the veys. Hardly any species’ age, some were contiguous conservation status and indeed it has been included old secondary forest in the Bua Alat river valley.

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Primate censuses and calculation of density Biomass

The abundance of Hose’s leaf monkeys was assessed Davies and 6.3 Payne (1982) report kg and 6.0 kg

using repeated line transect Transects were for adult surveys. an male and female Hose’s leaf monkey, situated in hill forest primary (four transects with and 3.0 respectively kg for an immature. Davies

a total of 10.75 riverine forest length km), primary estimated 4.5 for (1994) kg an average leaf mon- (one transect of4.9 km), old forest secondary (one key, irrespective of the in which it group size oc- transect of 3.3 and km), young secondary forest Davies curs. and Payne (1982) estimate 30 kg for (two transects 4.6 An walk- totaling km). average of 7 a group individuals and Suzuki (1992) at 56 1 ing speed of c. 1.5 km h' was maintained. A total kg for a group of eleven individuals. Given that of 258 km were thus covered, 119 km in primary Hose’s leaf monkeys occur in single-male, mul- hill forest, 29 km in primary riverine forest, 66 km tiple-female groups, biomass was calculated using in old and 44 km in secondary forest, young sec- average group mass following: ondary forest.

Densities ofleaf monkeys were estimated using = Mgwup 6.5 + (N - I x 4.8) (equation 3) the effective distance method of Whitesides et al.

(1988): where M = the average group mass (in kg), N = group n " total group size, and 6.5 the n (kg) average weight of (equation 1) A S / L(2Ed + 2) an adult male and 4.8 the (kg) average weight for

females and offspring. = -2 D = where density (groups km ), n number of

= 2 groups seen, A census area (in km ), L = length censused (km), Ed = Effective distance (km, esti- Vegetation sampling mated in and S = m), mean group spread (km, es- timated in m).

Vegetation characteristics were recorded Group spread is the diameter of the circle of at sam- stations established 150 pling every m equivalent area to that along occupied, on average, by a transects. Data 47 The were collected from primate group. effective distance is defined as sampling stations: 13 in each primary forest, 12 in old the distance on side of the transect at which secondary forest, 13 in the young secondary forest and 9 in river- number of sightings at greater perpendicular distances ine forest. Inspired by the work equals the number missed at nearer dis- ofTorquebiau (1986)

and Jones et al. an indication of tances. There was difference in (1995), the recent no significant per- of station pendicular distances between habitats (Kruskall- history each sampling was gained by the Walis H = > recording tree ‘architecture’. The of 2.3, p 0.50), and the effective distance height the first was determined major branching, combined with the using a histogram of perpendicu- presence lar or absence of scars the trunk distances from all habitat types combined: large on below this first bough, information on the Nt provide growth „

— Ed = x Fd conditions of (equation 2) the tree. In general, a tree with branches Nf above half its will have height grown up under a where Nt = total number of sightings, Nf = the closed and be considered canopy may probably a numberof sightings below the fall-off distance, and ‘primary forest’ tree, and those branching below Fd = fall-off distance, defined as the maximum halftheir have height usually grown up in a cleared reliable distance beyond which the number of areas (a ‘secondary growth’ tree). Following the sightings is reduced by 50% or more. method described in Nijman at each sam- The (1998), density of individuals was calculated using pling station four trees cm the (>10 dbh) were selected, mean group size, as observed during the transect the and height height of the first was esti- walks. For estimation of bough mean group size, only mated and the girth and distance to the complete of all members of the sampling counts group were station’s centre measured. used. point Vegetation cover

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was estimated the 5% at low branch at the stations smaller in to nearest ground, (2.0 sample was young m above ground), and canopy level. secondary forest than in old secondary forest (Mann

= = Whitney U, both n ( 12, n, 13, p < 0.01). Veg-

etation cover at low and ground level was highest

Analysis in riverine and young secondary forest, and lowest

in primary and old secondary forest (Kruskall-Wallis

of = < Each transect (apart from two of the transects in one-way analysis variance, H 13.3, p 0.01 primary hill forest from where not all vegetation and H = 19.0, p < 0.001, for ground and low level

data were collected) was characterised by the fol- cover, respectively). Conversely, estimated canopy

variables: cover was in and old lowing average tree distance, tree diam- higher primary secondary and lowest in riverine eter, tree height and height of the first bough; av- forest, young secondary and

the differences between forest how- erage vegetation cover at ground, low and canopy forest, types

not H = level; average altitude (range 325-450 m a.s.L); ever being significant (Kruskall-Wallis, shortest straight line distance to the nearest village 5.0, p > 0.1). Not unexpectedly, vegetation vari-

ables correlated (range 0.5-5.0 km) and to the nearest river (range were highly with one another (Ken-

dal Correlation > < 25 m-2.0 km). A multiple linear regression model Coefficient, t 0.67, p 0.05)

for was fitted on the (normalised) data to determine except distance to the nearest tree. the best sub-set of predictors for the observed va- riation in leaf densities. The effects of col- money

reduced Densities, and biomass linearity were by simply omitting pre- group sizes

dictor variables that correlated highly with the other the With 24 predictor variables that remainedin model an effective sighting distance of m for all

and habitat (Quinn Keough, 2002). Means are reported ± types combined and an average group spread

2 I standard deviation, and all tests are two-tailed of 11 m the total area was 15.2 km (n=9) survey . with assumed when < 0.05. Within this 24 significance p area groups were encountered giv-

of 1.6 km"2 ing an average groups . Although Hose’s

leaf monkeys were encountered in all forest types,

Results group densities were twice as high in primary for-

in est as the other habitat types (Table 2). Within

Vegetation the primary forest the monkeys preferred hill for-

est above riverine forest. Group densities along

transects in undisturbed forest and Primary forest has a much more open understory types (primary

in than secondary forest, yet no significant differences riverine) were significantly larger than the sec-

found forest in forest = = were between types the average ondary types (Mann-Whitney U, n, 5, n,

3, < distance from the nearest tree (>10 cm dbh) to sample p 0.03). Indeed, densities decreased with in- levels of forest disturbance. plot’s centre (Table I). This is mainly due to the creasing Group sizes

Hose’s fact that a great number of the trees in secondary of leaf monkeys tended to be larger in pri-

forest forests to had a diameter of <10 cm dbh and thus were mary compared secondary forests, i.e., not included in sampling. Primary forest and old 8.3±2.9 (n = 11) and 7.2±1.5 (n = 5) individuals,

forest differed but these differences not secondary significantly in average respectively, were signifi- height of the first bough and their diameter (Mann cantly different (Mann-Whitney U, n = 11, n = 5, 2

= > U = = and = 0.30). all habitat the mean Whitney n, 13, m, 12, p 0.03, n [ 13, p Combining types

= = size 8.0±3.0 = individuals n 12, p 0.05, for of first and group was (n 16) (range 2 height bough

Most diameter, respectively). Average tree height did not 1-11). groups consisted of a single adult male, differ between these two forest types, although the several adult females and their offspring, but an

in in range of values was smaller old secondary for- all-male group of four individuals was present

the est (10.4-18.6 m) than in primary forest (10.5-20.8 primary forest and several single individuals, m). Average tree height and height of the first major mostly males, were encountered. With an average

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Table I. in old and forest in National Vegetation structure primary, riverine, secondary, young secondary, Kayan Mentarang Park,

East Indonesia. Based 13 stations in hill 9 stations in riverine 12 Kalimantan, upon sampling primary forest, sampling forest, sampling

stations in old and 13 stations in forest. s,d.=standard deviation. Values with different secondary forest, sampling young secondary

letters are significantly different at the 5% level.

Primary Forest Secondary Forest

Hill Riverine Old Young

mean (s.d.) mean (s.d.) mean (s.d.) mean (s.d.)

height of tree (m) 15.2 (3.0) a 12.0 (2.3) c 13.5(2.6) a 9.9 (1.1) b

height first bough (m) 11.9 (2.5) a 7.7 (1.5) c 9.6 (1.8) b 6.8 (1.0) c

diameter (cm) 31.1 (9.8) a 21.9 (7.2) b 23.8 (8.8) b 17.5 (4.0) b

distance to station (m) 3.5 (1.2) a 3.4 (1.3) a 3,5 (0.7) a 3.4 (1.0) a

ground cover (%) 16.5 (24.7) a 54.4 (22.8) b 17.3 (18.6) a 45.4 (24.9) b

37.7 (18.3) b low level cover (%) 12.4 (6.2) a 16.3(9.1) a 43.5 (16.4) b

53.0 38.3 b ab 36.6 b canopy cover (%) (19.6) a (18.7) 50(19.9) (20.8)

Table 2. Densities of Hose’s leaf monkey Preshytis hosei in East Kalimantan, Indonesia.

2 2 Habitat No transects Repeats Census area Groups km' Individuals km'

2 (length in km) (km ) (s.d.) (s.d.)

Primary forest

Hill 4 (10.8) 44 7.0 2.3 (0.1) 18.9 (22.7)

Riverine 1 (4,9) 6 1.7 1.2 9.5

Secondary forest

Old 1 (3.3) 20 3.9 1.0 7.4

Young 2 (4.6) 19 2.6 0.8 (0.1) 5.5 (5.2)

of the used for group size of 8.0 individuals the average groupmass height tree upon encounter 34 indi-

in old in all forest types combined is 40 kg. This converts viduals primary and secondary forest was

2 in than to a biomass of 92 kg km' primary hill forest, significantly higher that of a random sample

2 48 kg km' in primary riverine forest, and 38 kg of 100 trees (dbh > 10 cm) in these forest types (Mann

2 31 km'2 U = = < The km' and kg for old and young secondary Whitney n 1 100, n, 34, p 0.01). me-

forest, respectively. dian altitude of the transects and distance to the

nearest village were positively correlated (Kendall

Rank Correlation = < Coefficient, t 0.80, p 0.02),

Correlations between densities and habitat reflecting a preference for establishing villages in

Leaf was cor- parameters valleys. monkey density positively related with increasing distance from the village

and distance to the Group densities of Flose’s leafmonkeys were posi- (Figure 1) increasing nearest

river Rank Correlation both tively correlated with tree height, height of the first (Kendall Coefficient,

t = < In a linear bough, tree diameter, and ednopy cover, and nega- 0.73, p 0.04). simple multiple re-

low gression model, tree diameter and distance to a tively with vegetation cover at and ground level.

it to be the best subset of However, only for the first two mentioned was village proved predictors

the in = significant (Kendall Rank Correlation Coefficient, for observed variation densities (F,, 33.5,

2 2 = R = 0.9: = t = < 0.02 = < 0.04 for tree p 0.001, km' 0.87, p and t 0.73, p Density (in groups )

-0.615 + 0.0682 Tree + height and height of first bough respectively). Hose’s Diameter 0.196Distance

leaf tall trees as the to monkeys have a preference for Village).

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common nearer to villages.

Several studies examined the effects of habitat

disturbance (including selective logging, shifting

cultivation and hunting) on other colobines in Af-

rica and Asia, but these studies reveal few consis-

tent trends, with some species declining and others

increasing (Skorupa, 1986; Davies, 1994; Grieser

Johns and Grieser Johns, 1995; Cowlishaw and

the Dunbar, 2000). Even within species of genus

trends in Presbytis few consistent emerge, bearing

mind, however, that there have been few diligent

have studies of this genus. Most species seem to a

clear preference for primary forest (Natuna leaf

monkey P. natunae: Lammertink et al. 2003; grizzled

leaf monkey P. comata: Nijman 1997, Nijman and

P. V. van Balen 1997; red leaf monkey rubicunda, Fig. I. Animal captures (data from Puri, 1992) and densities of Nijman unpubl. data), and the general trend is that Hose’s leaf monkeys in relation to distance to the village in after an initial decrease due to the immediate ef- which hunters reside showing anexponential decrease in hunting fects of the of leaf with logging operation, populations intensity and a linear increase in leaf monkey density

recover but to a below increasing distance from a village. monkeys quickly density

the previous level (Whitten et ah, 2000: 373). Payne

and Davies (1985) found that Hose’s leaf monkeys

were less common in a 19-year old logged forest

Discussion compared to two adjacent unlogged forests, with

knr 2 3.6 densities of 1.3 groups compared to and

The habitat disturbance 4.3 knr 2 More effects of groups respectively. generally, they

found leaf monkey (Hose’s and red) densities were

few document the effects 3-5 lower in This is one of studies to times in logged forest than unlogged

and Hose’s leaf in of habitat disturbance hunting on areas. Mitchell (1994) reported differences rang-

in 45 and 0-20 old monkeys. Group densities 1 year ing behaviour between two adjacent groups, one

30% 40% secondary forest were respectively and of which ranged in a 10-20 year-old lightly logged

less than primary forest. The smaller group sizes forest and the other largely in unlogged forest. The

in forest not are in- in forest had home and secondary (albeit significant) group logged a larger range

dicative of an even decrease in biomass. Mitchell furthermore re- greater larger day ranges. (1994)

have leaf 15-20 These changes come about as result of a com- ported the absence of Hose’s monkey in and it bination of habitat disturbance and hunting, year-old forest that had been heavily logged, sug-

is not possible to separate the effects of hunting gesting declining densities of Hose’s leaf monkey

it is from habitat disturbance on the species’ decline. with logging. However, not clear if this de-

Given the proximity of the study sites to one an- cline is due to the effects of logging or due to geo-

other and the homogeneity of the original forest, it graphical variation in densities. Wilson and Wil-

is dif- unlikely that other factors (such as spatial son (1975) found Hose’s leaf monkey only in pri-

ferences in number of the of but indicate that it did also occur in competitors, amount mary forest,

certain food diseases: reviewed in Davies stud- sources, or disturbed forests. Bennett and Dahaban (1995)

1994) are major contributors in these observed differ- ied the effects of disturbance (including logging

in and other than leaf ences density biomass, those in- and hunting) on densities of four species of

duced habitat disturbance and by or hunting, e.g., monkeys (including Hose’s leaf monkey) in Sarawak

the of certain food amount sources may change after and Brunei. In general, densities of leaf monkeys

and other be logging, primate species may more differed little between eight primary forest plots

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and two 30-year old secondary forest sites, or be- life (cf. Robinson and Bennett, 2000). In Bennett

tween forest site and one prior to logging one year and Dahaban’s (1995) study, the effect of hunting

after leaf logging. on monkeys was considerable (from an aver-

2 In contrast to the above studies that either of 5.1 knr in reported age density groups three sites with a

decrease in densities 2 a due to or were not low 2.7 and 0.5 logging hunting intensity, to groups knr

able to detect an effect on Johns in four densities, (1992) and one forest sites with medium and high in reported an increase density of Hose’s leaf mon- hunting intensity, respectively) yet not statistically after from 2.0 knr2 in key logging, groups primary significant.

2 forest to 3.6 knr in forest 6 after of groups years Analysis data on hunting in Kayan Mentarang

3.9 2 forest 12 logging to knr in after at a site c. 12 km south of groups years my study area presented Wilson and Johns data from Puri logging. (1982), using by (1992) might shed some light on the rela-

East Kalimantan, foundthat leaf were monkeys able tionship between hunting intensity and the distance

to withstand the pressures imposed by logging. from the village where the hunters live (Figure 1). shows It an exponentially decreasing relation be-

tween hunting intensity and distance to a village at

The a scale effects of hunting very similar to the observed increase in

densities of Hose’s leaf monkey with increasing

Kuchikura showed that in Ma- distance to a found in (1988) peninsular village the present study. A

laysia two species of leaf monkey (pale-thighed leaf significant correlation was demonstrated between

Hose’s leaf monkey P. siamensis and dusky leaf monkey Tra- monkey densities and distance to vil-

the and and chypithecus obscurus) were most profitable lages rivers, distance to villages was in-

in of of rate for cluded in the best primates terms rate energy gain subset of variables explaining hunters. variation Nevertheless, primates contribute less than in Hose’s leaf monkey densities. Although a quarter of the entire mammalian harvest in most these data provide only circumstantial evidence and hunter communities (Cowlishaw and Dunbar, 2000). are by no means conclusive, it does indicate that

Indeed in the Kayan Mentarang area pigs and not hunting (perhaps in combination with habitat dis-

has an primates comprise most of the prey. Still, hunting turbance) impact on population numbers of ofHose’s leaf is Hose’s leaf Other monkeys a widespread occurrence monkeys. primates, especially

in those as five skins were observed mounted on walls occurring at low densities or whose behaviour four and an additional three makes them to villages, (most likely susceptible hunting might be more

Hose’s) leaf monkey skulls were present in two affected than Hose’s leaf monkey. MacKinnon

hunt- the almost villages (V. Nijman unpubl. data). On Borneo, (1992) suggested total absence of oran-

ofleaf is often associated with inland in north-east ing monkeys gutans Kalimantan, including the Kayan

the demand is caused settlements, the timber industry and Mentarang area, by hunting. The same for bezoar stones (visceral secretions used in tradi- might explain the scarcity of proboscis monkey in tional medicine and sold for high prices). Near the area (Pfeffer, 1958; Meijaard andNijman 2000a). villages they are hunted to deter crop-raiding. In

West Kalimantan, encounters with primates by

Dayak hunters were as likely to result in a capture Conservation prospects in the interior ofBorneo as encounters with other large mammals, although

were encountered the 2 primates infrequently (Wadley Despite gazetting of several large (>1000 km ) et In the three leaf in Indonesian ah, 1997). Sarawak, monkey protected areas Borneo, due to a com- species (red, Hose’s and white-fronted leaf mon- bination of mismanagement, poorly integrated plan- key account for at least one of institutional P. frontata ) percent ning, deficiencies, and misconceptions all mammals hunted, which account for some on may ecological issues, virtually all forest in protected 20 000 monkeys annually (Bennett ct ah, 1987). areas have been affected by logging, burning and

Borneo However, few studies on have systematic conversion (Meijaard andNijman 2000b; Fredriks-

& cally investigated the effects of hunting on wild- son Nijman, 2004). The only large undisturbed

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in far inte- 66-86. forest areas on Borneo are the island’s

Bennett Caldecott Sebastian A. 1987. rior. due EL, J, Kavanagh M, Probably more to luck and (as yet) poorly Current status of primates in Sarawak. Primate Conserv. developed infrastructure, so far these regions have 8: 184-187. more or less escaped and, in comparison with low- Cowlishaw G, Dunbar RIM. 2000. Primate conservation coastal wildlife thrive. lying areas, seems to Large biolog)’. London and Chicago: University ofChicago Press. sections of the remaining forest in Borneo’s inte- Davies AG. 1994. Colobine populations. In Davies GA, Oates JF, eds. Colobine monkeys: their ecology, behaviour and rior are included inside logging concessions or are evolution. Cambridge: Cambridge University Press, 285- scheduled for conversion. The two largest areas that 310.

at least on are the are, paper, adequately protected A Sabah. Kuala Davies AG, Payne J. 1982. faunal survey of and the / Kayan Mentarang Betung-Kerihun Lanjak Lumpur: World Wildlife Fund Malaysia.

Entimau transboundary reserves in West Kalimantan Fredriksson GM, Nijman V. 2004. Habitat-use and conser-

vation of two elusive ground birds (Carpococcyx radiatus and Sarawak (MacKinnon et at., 1996). Although and Polyplectron schleiermacheri) in Sungai Wain Pro- it does not this may secure the rain forest, exempt tection Forest, East Kalimantan, Indonesian Borneo. Oryx wildlife from the dangers of hunting. In Indone- 38: 297-303. sian law enforcement is absent reserves, virtually Gricser Johns AD, Griescr Johns BD. 1995. Tropical for- and in and around both reserves there are numer- est primates and logging: long-term coexistence? Oryx

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