|Scientific Name:||Muntiacus atherodes Groves & Grubb, 1982|
|Taxonomic Notes:||This Bornean endemic was described as a new species by Groves and Grubb (1982). Although the species had been recognized as different from the 'typical' M. muntjak of Borneo (then referred to as M. m. rubidus, but this name is antedated by M. m. pleiharicus) for many years (e.g. Van Bemmel 1952), the assumed name for it, M. pleiharicus, had in fact been assigned to a specimen of M. muntjac (Groves and Grubb 1982), hence the need to propose a new name (note that Cervulus pleiharicus Kohlbrugge, 1895 was included as a synonym of this species in previous Red List assessments but is now removed to avoid confusion). There is no question of the validity of M. atherodes as a species, because it has multiple diagnostic features and is widely sympatric with Southern Red Muntjac M. muntjak (Groves and Grubb 1982, 1990); but identification to species, particularly on field views and typical camera-trap photographs, of the two muntjacs on Borneo is difficult, and many observers have therefore considered it sensible to present survey results only as 'muntjac sp(p)'. This caution is far preferable to cavalier identification to species, but it results in a slim information base from which to assess the extinction risk of this species.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor(s):||Timmins, R.J., Belden, G., Brodie, J., Ross, J., Wilting, A. & Duckworth, J.W.|
|Reviewer(s):||Brook, S.M. & McShea, W.J.|
Muntiacus atherodes apparently remains widespread and at least locally common. Although data strongly suggest it is predominantly a lowland species, it occurs substantially above the level lowlands; in these latter areas the pace of forest conversion is alone sufficient to result in listing as Vulnerable or Near Threatened for forest obligates even of somewhat shorter generation lengths (see BirdLife International 2001), but this muntjac appears to have too wide an altitudinal range for this to be applied. However, forest loss even up to 750 m has been significant (probably around 15% between 2000 and 2010) and some preliminary data suggest that the species is strongly associated with gentle terrain and avoids rugged areas and steep slopes, which could mean that the loss in terms of M. atherodes numbers has been an even higher proportion.
Muntjacs are subject to intense harvesting in at least some areas of Borneo, and there is good evidence from Malaysian Borneo that this depresses population densities significantly. There is also evidence that Yellow Muntjac is more scarce in logged than in old-growth forest, in contrast to the pattern shown by sympatric M. muntjak. Hunting, logging and post-logging conversion to non-forest are ongoing and can be predicted to continue to reduce populations. However, this species remains common in some areas with both heavy hunting and habitat conversion. Therefore, rates of decline cannot be calculated or even easily inferred (even of muntjac spp. in general, let alone of determining whether M. atherodes is changing in relative frequency).
Concerning the appropriate red list category for this species, there was little convergence of opinion during the 2008 assessment among people surveying mammals on Borneo, except that it was unlikely to fall in any of the threatened categories. Since 2008 what data there are have leant more weight to the probability that the rate of decline could be more substantial than generally conceived; after all detecting even 20% declines in inherently ‘common’ and widespread species is likely to be very difficult on the basis of largely ‘incidental’ data. During the 2008 assessment some felt strongly that it was unlikely that Bornean Yellow Muntjac could be declining fast enough to warrant listing even as Near Threatened. However, with hindsight, it now seems also plausible that when considering potential combined impacts of forest loss, logging and hunting in light of increasing understanding of the species’ ecology, that listing as Vulnerable under scenario A2cd is conceivable. Thus, with reservations, it is listed here as Near Threatened considering that there is reasonable likelihood that declines in the past fifteen years have exceeded 20% and might even have been significantly higher, yet it is an assessment based on few precise data, at times contradictory, and which warrants review whenever a clearer picture is available.
|Previously published Red List assessments:|
|Range Description:||This species occurs only on Borneo, and lives throughout the island; many specific localities are given in Groves and Grubb (1982). No information was traced concerning its presence in Brunei but presumably it lives there. It is present in both Indonesia (Kalimantan) and Malaysia (Sabah and Sarawak). The Bornean Yellow Muntjac is known from most of the forest protected areas in Sarawak, including Bako National Park, Lanjak-Entimau Wildlife Sanctuary, Similajau National Park, Lambir Hills National Park, Samunsam National Park, Gunung Gading National Park (in the lowland part), Mulu and Niah National Park, and has also been recorded in logged forest in the Bintulu area and in oil palm adjacent to recently logged forest in north-east of Bintulu (Belden Giman pers. comm. 2008).|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species appears to be widespread and often common throughout its range, wherever appropriate habitat occurs (Yasuma and Abdullah 1997, Belden Giman pers. comm. 2006; see further discussion in the Habitats and Ecology section). Numbers seem to be in some decline in the Indonesian part of Borneo (Semiadi 2006). They may also be in decline in Malaysian Borneo (Bennett et al. 2000), although this study did not distinguish the two species of muntjac. Around the Bintulu lowlands the species remains common despite major habitat disruption and high levels of hunting relative to the region (Belden Giman pers. comm. 2008).|
Forest loss on Borneo below 750 m has been calculated as ca 16.5% between 2000 and 2010, this figure includes both peat swamp and mangrove forest where percentage losses have been higher than other forest types (derived for Borneo from Miettinen et al. 2011), however it seems likely that in forest types used by M. atherodes the loss has been over 10% and likely even over 15% (A. Wilting pers. comm. 2014). However there is evidence from at least one area that the species is able to use plantation forests (see the Habitats and Ecology section), which could mean that the percentage population decrease of M. atherodes below 750 m as a result of forest loss is somewhat less than the percentage loss of forest would suggest. Evidence from at least two separate studies suggests (see the Habitat and Ecology section) that significant population decline occurs during intensive logging operations, and that significant population depression continues for years after logging has ceased. Suggesting that even in remaining forests below 750 m [Between 1973 and 2010 an estimated 37.8 % of forest has been lost and an additional 34% of forests below 500m have been logged in some way (Gaveau et al. 2014)] significant population declines have taken place. Hunting has been considered a significant issue for the species in many lowland areas, both logged and unlogged (see the Threats section) and this has undoubtedly resulted in further population reductions above and beyond those simply resulting from habitat changes as a result of logging or forest loss.
Estimating the true population reduction over ca the last 15 years (assuming a generation length of ca 5 years) is extremely difficult, however a suspected decline of 20-25% seems quite plausible, in view of the likelihood that the species has a predominantly lowland distribution and favours gentle terrain (see the Habitat and Ecology section).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||Payne et al. (1985) stated that “available data suggests that this species predominates over the Red Muntjac in low hill ranges and coastal regions”, but Meijaard and Sheil (2008) pointed out that still “no robust quantitative data exist to support this [pattern]”. An incomplete review of altitudes associated with museum specimens by R.J. Timmins (pers. comm. 2008) suggests no readily apparent difference between M. atherodes and M. muntjak in the altitudes of historically collected animals, in fact there appear to have been very few muntjacs collected at altitudes over 900 m, presumably partly reflecting the relatively small area of Borneo above such altitudes (Timmins et al. pers. comm. 2008). There is, however, an opinion by many field observers that Bornean Yellow Muntjac is genuinely absent from mountains (Timmins et al. pers. comm. 2008), yet there are specimen records from over 900 m and camera-trap records from over 1,100 m (R. J. Timmins pers. comm. 2015, Hearn et al. unpub. data).|
Based on camera-trapping undertaken between 2008 and 2010 in Sabah in three forest areas all identifiable muntjac photographs were of M. atherodes. The three forest areas were Deramakot (FSC certified and well managed) [below 400 m] in which there were 1,916 trap-days of effort, where muntjacs were recorded from 27 of 48 camera stations, and out of these 18 had confirmed M. atherodes, Tangkulap (more disturbed by conventional selective logging but logging stopped 10 years ago) [below 400 m] in which there were 2,203 trap-days of effort, where muntjacs were recorded from 6 of 64 camera stations, at all six with confirmed M. atherodes, and Segaliud Lokan (also more disturbed by conventional selective logging, only RIL logging is being continued) [below 400 m] in which there were 2,933 trap-days of effort, where muntjacs were recorded from 11 of 58 camera stations, and out of these 10 locations had confirmed M. atherodes. M. muntjak by comparison was not definitely recorded, although single individuals photographed in Deramakot might have been this species and a female and fawn in Segaliud Lokan were probably this species. All three sites are lowland forest reserves and both Deramakot and Tangkulap had high patrol effort by rangers from Sabah Forestry Department during the study, no evidence of hunting was found during the project. In Segaliud Lokan rangers reported that sometimes they encountered hunters in the forest during patrolling, although no evidence of hunting was found during the project (all information from A. Mohamed and A. Wilting pers. comm. 2014).
It was common in Sungai Wain forest, Kalimantan, which spans 30–150 m asl, and clearly out numbers M. muntjak there (G.M. Fredriksson pers. comm. 2008). It also seems to be the predominant species in Sarawak Planted Forests, Bintulu Division, a mix of Acacia mangium plantation and natural forest, where it uses mature and immature plantation, freshly logged forest and relict tall forest, nearby it has also been found in oil palm (Belden et al. 2007, Belden Giman pers. comm. 2008). Since the 2008 assessment the population in this lowland area seems stable (Belden Giman pers. comm. 2014). In this mosaic region the majority of camera-trap photos have come from plantation areas rather than natural forest, and although harvesting has taken place in the plantations this seems not to have affected the muntjac population (Belden Giman pers. comm. 2014). In the Ulu Segama area of Danum Valley Conservation Area, Sabah, mostly at about 300 m Asl, M. atherodes was slightly more common than M. muntjak (Siew Te Wong pers. comm. 2008). Muntjacs were frequently seen, suspected to comprise roughly equal numbers of the two species, in the Batang Ai National Park, Sarawak, which lies mostly at 100–760 m asl (Meredith 1996). M. atherodes occurs down to sea-level (in e.g. Similajau National Park, Sarawak, Duckworth 1997) and up to at least 3,000 feet (approximately 900 m asl), based on specimens in the Field Museum (Chicago, USA, R. J. Timmins pers. comm. 2008). Mohd Azlan J. (pers. comm. 2008) has recorded muntjacs provisionally recorded as this species in hill dipterocarp forest at both Lambir Hills National Park and Lanjak Entimau Wildlife Sanctuary. Field observation suggests that it occurs naturally only below 1,000 m asl, although semi-captive individuals live as high as 3,000 m asl (Belden Giman pers. comm. 2006). Camera-trapping between 2010 and 2012, in 15 sites in Sabah and Sarawak recorded many muntjacs, based on provisional identification of the photos, it appeared that the two species may have had approximately similar abundance below ca 300 m, but M. atherodes abundance declined very quickly with increasing elevation, the preliminary review of the data also suggested that M. atherodes abundance was lower in logged areas than in unlogged areas, while M. muntjak abundance was not discernably affected by logging (Brodie unpublished data, J. Brodie in litt. 2014).
Preliminary camera-trapping results from nine different forest reserves and protected areas across Sabah found high naive occupancy results for Yellow Muntjac from lowland sites, but low occupancy at highland sites, however the highest detections were from over 1,100 m (Hearn, Ross and Macdonald, unpublished data). It uses both primary and secondary forest (Matsubayashi and Sukor 2005, Belden Giman pers. comm. 2008), although no specific information is available on its tolerance to severe degradation and fragmentation. Preliminary analysis of muntjac records from camera-trapping between 2010 and 2012, in eight sites in Sabah and Sarawak, suggest the species might have lower abundance in newly logged forest, whilst M. muntjak abundance potentially was higher, compared with unlogged forest (Brodie unpublished data, J. Brodie in litt. 2014). Preliminary results from 9 different forest reserves and protected areas across Sabah also suggest Yellow Muntjac may be negatively affected by logging whilst Red Muntjac may be less affected (Hearn, Ross and Macdonald, unpub. data). Presumably M. atherodes cannot survive complete forest conversion, but this has not been demonstrated or even, it seems, specifically investigated.
Its diet includes herbs, seeds, grass and fruits (Payne et al. 1985). It is mostly active during the daytime (Payne et al. 1985, Yasuma and Abdullah 1997, Ross et al. 2013) but at least sometimes at night (Duckworth 1997). It lives in small territories and moves either in pairs or alone (Payne et al. 1985). Breeding seasonality is unknown.
|Generation Length (years):||5|
|Use and Trade:||The Bornean Yellow Muntjac is hunted for meat, skins, and as a source of traditional remedies. It is not usually kept as livestock.|
Habitat encroachment and hunting are both widespread on Borneo. Indeed, they are often associated and all the island’s ungulates suffer from the increased hunting that often accompanies logging (Bennett and Dahaban 1995, Bennett and Gumal 2001), such that hunting to local extinction is the chief detrimental effect of logging on ungulates in Sarawak (Bennett and Gumal 2001). Hunting is for meat, medicine and hides.
The extent to which habitat encroachment and hunting constitute threats specifically to M. atherodes is unclear, reflecting a paucity of studies to determine its resilience. Logging has been reported to lead to slight decreases in densities of the species, and this seems to be due to habitat change per se rather than elevated hunting (which usually accompanies logging; Bennett and Gumal 2001) because M. muntjak in the same study was found to increase strongly after logging (Heydon 1994). In the Sarawak Planted Forests, Bintulu Division, Sarawak, muntjacs (probably mostly this species) are among the commonest species camera-trapped in young Acacia mangium plantations (under four years old) and have been seen browsing on young acacia shoots. Footprints are common in the adjacent newly planted areas and forest fragments (Belden Giman pers. comm. 2008). However, this area contains a substantial proportion of natural, if somewhat degraded, forest, which in theory might be found to be necessary for populations in the highly altered habitats. Information on the species in landscape-scale plantations has not been traced. In terms of coping with fragmentation, M. atherodes has survived at least for several years in several forest isolates of 100 km² or less, Similajau National Park (Sarawak; J.W. Duckworth pers. comm. based on observations in 2005), Sepilok Forest Reserve (only 42 km²; muntjacs not confirmed as this species; Siew Te Wong pers. comm. 2008), and Sungai Wain (Kalimantan; G.M. Fredriksson pers. comm. 2008); in the latter, where there is little hunting except around the margins, it is common. But the current carving up of the formerly extensive forest of lowland Borneo is so recent that determining long-term persistence in such fragments is impossible; doomed populations in slow but fixed decline may account for records in fragmented and degraded areas. There is no good evidence that any muntjac is tied to old-growth forest, however, even in areas where two or more species are sympatric (R.J. Timmins pers. comm. 2008).
Muntjacs are widely and heavily hunted on Borneo for meat, skins, and as a source of traditional remedies (Bennett et al. 2000; Mohd Azlan J. pers. comm. 2008; Belden Giman pers. comm. 2008; G. M. Fredriksson pers. comm. 2008; A. C. Sebastian pers. comm. 2008; Siew Te Wong pers. comm. 2008). Traditionally, hunting used traps, dogs and spears, and blowpipes. Hunters in remote parts of the interior still use these methods, but most animals now die by gunfire. Sarawak held 60,000 legally registered shotguns while Sabah held almost 13,000 in the mid 1990s (Bennett et al. 2000). Methods used in Indonesia include guns and spotlights along logging roads, snaring, and dogs (G. M. Fredriksson pers. comm. 2008). The combination of dogs and guns may be particularly efficient (Belden Giman pers. comm. 2008). Snaring is still very heavy for the region (although bears no comparison to the extremely intensive snaring levels found for instance in Vietnam, outside well-secured areas, but at least in some areas seems not to catch many of this species: Belden Giman (pers. comm. 2008) found during interviews with 75 longhouses inside the Sarawak Planted Forests (Bintulu) that the highest percentage (73% and 12%) of game species caught by snares were pigs and porcupines respectively; muntjacs (both species) totalled less than 2% of animals, even though in this area they are common. Shotguns remain the even bigger problem (Bennett et al. 2000; Mohd Azlan J. pers. comm. 2008; Siew Te Wong pers. comm. 2008). Unaccompanied packs of stray or even perhaps feral dogs are also likely to be a threat, particularly in forest isolates close to urban areas (e.g. Similajau National Park; J.W. Duckworth pers. comm. 2008). It is unlikely that hunters make any distinction between the two Bornean muntjac species directly, although it is plausible that M. atherodes is under higher hunting pressure than is M. muntjak reflecting its purported predominance in the lowlands, where most of the logging concessions currently lie. Plantation estates are also concentrated in the lowlands, but Bennett et al. (2000) found that hunting levels in them were low, not least because they supported so few animals that would-be hunters preferred to journey to forest areas. Even when these were nearby, few labourers were hunting, because of the demands of their job, and, crucially, the disincentives by plantations companies for them to own shotguns. As non-locals with limited financial security, most followed employer rules preventing ownership of guns. Experience elsewhere shows that in such situations, local hunters may see such concentrations of labourers as potential markets, therefore leading to an increase in hunting even though it is not undertaken directly by the labourers. As plantations cover ever more Bornean lowlands, this may become a more significant stimulant of hunting. Also, although some ethnic groups, at least the Punan, have traditional beliefs against eating muntjac meat (Belden Giman pers. comm. 2008), over most of (at least) Malaysian Borneo, “in general, everyone will hunt and eat anything” (Bennett et al. 2000). Much hunting is for the market rather than local use, so there is a limitless demand. Bennett and Gumal (2001) profiled the hunting of ungulates in Sarawak in the mid 1990s thus: muntjacs (along with Bearded Pig Sus barbatus and Sambar Rusa unicolor) are heavily shot for wild meat trade across Sarawak, and these ungulates are the species most sought by the restaurants. Wild meat is widely sold in towns, villages, restaurants and logging camps throughout Sarawak; 250 sales outlets were estimated across the state in 1996, with an annual trade worth 3.75 million USD. Along the Rejang river alone, in the mid 1980s, 250 muntjacs were sold per year (Caldecott 1988). The market for meat is great and in the 1990s was probably expanding. There were, then, no controls on commercial hunting of non-protected species (including muntjacs). The implementation of the Master Plan for Wildlife in Sarawak (Wildlife Conservation Society and Sarawak Forest Department 1996) introduced a strict ban on all wildlife trade, shotgun ownership and cartridge sales in the late 1990s (Bennett and Gumal 2001). Substantial numbers of muntjacs are, nevertheless, still killed in the state, as they are elsewhere in Borneo.
Bennett et al. (2000) considered the effects of this onslaught upon muntjacs (not distinguished to species) through a lengthy hunting study in February 1993 to June 1995, in both Bornean states of Malaysia (Sarawak and Sabah), each with eight study areas. Muntjacs constituted only 4–11% of animals killed, but index counts of signs show an inverse relationship between sign index and hunting pressure so strong that the latter over-rode the effects of habitat variables in determining their densities. Hunting was so ubiquitous, even in protected areas, that in the two states, only one site (part of Danum Valley, Sabah) could be found as a control, where there was primary forest but negligible hunting levels. They concluded that “the only single factor offering any effective protection for [quarry species of] wildlife is difficulty of access”; whether animals are protected or non-protected species, inside or outside protected areas, had no significant restraint on hunting levels. Since that study, much forest has been converted and muntjac populations in the smaller and more isolated areas that remain must now be more vulnerable to local extinctions.
Against this backdrop of evidence for widespread hunting of muntjacs, the M. atherodes population in Sarawak Planted Forests, Bintulu Division appears to have been stable between 2008 and 2014 despite some ongoing illegal hunting; in this area pigs Sus and Sambar Rusa unicolor appear to be the primary quarry (Belden Giman pers. comm. 2014).
Yellow Muntjac is known from many protected areas in Malaysia and Indonesia. Protected area coverage in the lowland plains is still relatively limited in Borneo, and many areas are, in terms of forest ungulate protection, sufficiently small (under 100 sq. km) that long-term persistence cannot be assumed; most places will require continuous hands-on activities against poaching. Even protected areas are not securing lowland forest on current trends, at least in some parts of Borneo: Curran et al. (2004) demonstrated substantial loss of lowland forest within protected areas of Indonesian Borneo. Indonesian forestry law protects all species of muntjac (D. Martyr pers. comm. 2008).
Heavy hunting with shotguns was found to be a severe problem for larger mammals and birds across Sarawak and the need for its control (of guns and of sale of ammunition, with firm legal underpinnings) was recognised in the Master Plan for Wildlife in Sarawak (Wildlife Conservation Society and Sarawak Forest Department 1996). As everywhere, people devise ways for circumventing the controls (illegal trade in bullets and locally made shot-guns, called bekakok, which have no administrative or legal paper-trail) and strong enforcement is required for the foreseeable future.
The long-term persistence of large populations of Bornean Yellow Muntjac, as distinct from isolated populations in well-secured protected areas, will depend upon their ability to use plantation landscapes of oil palm, rubber, acacia and others. Clarification of this is needed to assess the species’s conservation priorities. Of particular concern is the finding from Sabah suggesting that M. atherodes may be more a species of old-growth forest and M. muntjak the predominant species of logged areas (Heydon 1994). It is urgent to determine whether this is a generally applicable pattern across Borneo.
Close liaison with plantation estates and other employers of large numbers of labourers is essential as this offers the best medium to control hunting by employees. As the proportion of plantation rises this will become ever more important. Similar arrangements are needed with logging concession-holders, even more importantly because of the high hunting levels by and/for loggers.
In future studies, ways of enhancing information specific to muntjac species need to be sought and implemented. Many of the studies reviewed here would not, for example, have detected wild changes in the relative proportions of the two muntjac species within their results concerning muntjac spp. This is a major concern, given that M. atherodes is likely to be most everywhere sympatric with M. muntjak. With cheap digital cameras now available, some form of photography, by the hunter, of each animal killed should be considered (and this would be beneficial for other Bornean genera with closely similar species, e.g. chevrotains Tragulus). Most of the grey literature was not available to the present review and much could be learnt from a more comprehensive trawl of it and of active surveyors.
|Citation:||Timmins, R.J., Belden, G., Brodie, J., Ross, J., Wilting, A. & Duckworth, J.W. 2016. Muntiacus atherodes. The IUCN Red List of Threatened Species 2016: e.T42189A22166396.Downloaded on 23 September 2017.|
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