Rucervus eldii 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Mammalia Cetartiodactyla Cervidae

Scientific Name: Rucervus eldii (M'Clelland, 1842)
Common Name(s):
English Eld's Deer, Brow-antlered Deer, Thamin
French Cerf d'Eld
Spanish Ciervo de Eld
Cervus eldii M'Clelland, 1842
Panolia eldii (M'Clelland, 1842)
Taxonomic Notes: Most sources before 2005 placed Eld's Deer in the genus Cervus, but Grubb (2005) revived Thomas’s (1918) assignment of the species to Rucervus. However, Pitra et al. (2004) using analysis of mtDNA of many deer taxa demonstrated that placement of Eld's Deer in Cervus had been, in fact, phylogenetically more appropriate; it certainly does not belong in Rucervus (Groves 2006). Placement in the genus Panolia (as used by Pocock 1943) could be an acceptable alternative and was proposed by Groves and Grubb (2011) based on mtDNA analysis of Pitra et al. (2004). Based on the Phylogenetic Species Concept, Groves and Grubb (2011) recognized three ‘species’ of Panolia: P. eldii, P. thamin and P. siamensis supported on the basis of morphological and mtDNA analysis. The species name is often mis-spelt eldi, but the correct original spelling, which must be used today, is eldii.

Phylogeography studies support the recognition of three subspecies (Balakrishnan et al. 2003), with their ranges as follows: R. e. eldii, India; R. e. thamin, Myanmar, westernmost Thailand (Bhumpakphan et al. no date); R. e. siamensis, Cambodia, China, Lao PDR, Thailand (excepting southwestern most; Bhumpakphan et al. no date), Viet Nam.

Validation of, and the ultimate basis of identification of animals for, the various stated distributions of R. e. thamin and R. e. siamensis in Thailand are obscure and have not been researched for this account; such research however is warranted especially in view of the taxonomic status of these two subspecies and in relationship to reintroduction efforts in Thailand.

Although R. e. eldii (Sangai) is apparently very closely related to R. e. thamin based on genetic studies, it has significantly different ecology from other subspecies as well as apparently being the more divergent in morphology (Balakrishnan et al. 2003). The Chinese subpopulation on Hainan island has at times been considered a separate subspecies R. e. hainanus, but there appears to be little to support this stance (Balakrishnan et al. 2003).

Assessment Information [top]

Red List Category & Criteria: Endangered A2cd+3cd+4cd ver 3.1
Year Published: 2015
Date Assessed: 2014-05-02
Assessor(s): Gray, T.N.E., Brook, S.M., McShea, W.J., Mahood, S., Ranjitsingh, M.K., Miyunt, A., Hussain, S.A. & Timmins, R.
Reviewer(s): Duckworth, J.W. & González, S.

The species is considered Endangered based on estimated rates of decline which, averaged across the species, exceed 50% in three generations (presumed to be at least 15 years, see Song 1996). However potential rates of future population decline in both core populations (see below) may approach thresholds (>80%) sufficient to merit a change in status to Critically Endangered in the near future. Monitoring and collating the extent of habitat loss and loss of populations over the next 5-10 years is required.

There are two numerically significant units (defined through threat profile, recent history and short-term prospects, not as populations in any demographically meaningful sense) of wild Eld’s Deer, R. e. thamin in Myanmar and R. e. siamensis of Cambodia, Lao and Viet Nam (of which the overwhelming majority of animals are in Cambodia). Numbers in India are numerically less significant for determining species-level population trends and the semi-captive herds in Hainan (now increasing) are excluded as are introduced Thai subpopulations. Since the 2008 assessment rates of habitat loss and degradation within the species’ preferred lowland deciduous forest in Indochina, which supports the majority of the wild R. e. siamensis population, have accelerated due to expansion of economic and social land concessions into previously remote forested areas in Cambodia’s northern and eastern plains. This is impacting both protected and non-protected forests and no Eld’s Deer subpopulations are thus effectively secure. Given this threat (and the presumed status of the Myanmar subpopulations see below) regular re-assessment of the species’ IUCN categorization is merited. In addition, the Cambodian subpopulations are small (potentially none exceeding 50 mature individuals), functionally isolated, and largely outside the core zones of protected areas. All subpopulations also remain impacted by hunting.

The status of the Myanmar subpopulations is also likely to be declining due to a combination of habitat loss and hunting. Recent (2014) evidence from Myanmar indicates considerable loss of suitable lowland deciduous forest in central Myanmar and a potentially significant decline at one of the countries two core sites (Chatthin Wildlife Sanctuary) (W. McShea in litt. 2014). The Manipur subpopulation is stable but its small size (approximately 100 individuals; Hussain et al. 2009, M.J Ranjitsinh in litt. 2014) and threatened habitat in a single small protected area leave little cause for long-term optimism.

For the species to be categorised as Critically Endangered in the future (criteria A), an 80% decline over c. 15 years would be required, which would be likely to entail, assuming a stable Manipur subpopulation, the complete loss of Eld’s Deer populations from the remaining (one or two) sites in Lao PDR, and local extinctions from all but one protected area population in each of Cambodia and Myanmar. This scenario has not occurred, yet is possible but, perhaps, not likely. and therefore we maintain the previous assessment of Endangered. Regular monitoring of both rates of habitat loss and the status of core populations in both Cambodia and Myanmar is of critical importance for this species

Previously published Red List assessments:

Geographic Range [top]

Range Description:This species was formerly widely distributed across suitable habitats of South and Southeast Asia, from the Manipur region of northeastern India through much of Myanmar, Thailand, Lao PDR, Cambodia, and Viet Nam to the island of Hainan (China) in the east (Salter and Sayer 1986, Grubb 2005). The historical range was broken into four major components, consisting of the Manipur region of India inhabited by R. e. eldii; R. e. thamin on the central plains of Myanmar; R. e. siamensis populations in the lowlands of Thailand, Cambodia, Lao PDR and Viet Nam (separated by the mountains along the Thai-Myanmar border from R. e. thamin); and the population on Hainan and former populations in mainland southern China, which appear to have been disjunct outliers of R. e. siamensis, separated from its main range by mountainous terrain in Lao PDR and Viet Nam.

The global Eld's Deer population is currently very localized to small areas within the species' former range. R. e. eldii is now confined to a single small population at the southern end of Loktak Lake in Manipur, India (Singh 2004). R. e. thamin still occurs in several localised areas of central Myanmar, as well as there being introduced populations in Thailand (McShea et al. 2000, Aung 2004, Naris Bhumpakphan et al. 2004). R. e. siamensis occurs in one or two small localised populations in Lao PDR (Johnson et al. 2004), and as scattered small subpopulations mainly in the northern and eastern lowlands of Cambodia (Tordoff et al. 2005), and occurs in a relatively wild state in one protected area on Hainan, with additionally several other managed herds on that island (Pang et al. 2003).
Countries occurrence:
Cambodia; China; India; Lao People's Democratic Republic; Myanmar
Possibly extinct:
Thailand; Viet Nam
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Based on both habitat extent and size of remaining patches, Myanmar and Cambodia are the pre-eminent countries for Eld's Deer (McShea et al. 2005). However, the actual status of remaining populations is more related to hunting levels.

In Cambodia declines since the late 1950s, when large herds were still readily seen (Wharton 1957), have been dramatic. In the first decade of the 21st century the species declined by 90% or more, given comparisons of aerial counts in 1994 with ground survey results from 1998 to 2008 (Olivier and Woodford 1994, Timmins and Ou 2001, Timmins et al. 2003, R.J Timmins pers. comm. 2008). Eld’s Deer may still occur over a relatively wide area, although localised within this, surviving as small remnant groups in the lowland forests of the north and east. The 2008 account suggested the total Cambodian population “could well be several thousand animals in a forest area that probably exceeds 20,000 km2”. However the current population is more likely <700 individuals in a number of functionally isolated subpopulations despite remaining habitat. As a result of the scattered nature of the small Eld’s Deer subpopulations across northern and eastern Cambodia few occur within the cores of managed protected areas. 

Survey work in appropriate habitat between 1998 and 2008 detected subpopulations in at least 15 separate areas, with anecdotal evidence from several more areas (McShea et al. 2005, Tordoff et al. 2005, Bird et al. 2006, Timmins 2006, Bezuijen et al. in press). A few may remain in the southwest, although there is little evidence other than for one small subpopulation in the Phnom Aural area which persisted until at least the late 1990s (Henshaw et al. 2002, Tordoff et al. 2005), but there is no more recent information. Gray et al. (2012) reviewed camera-trap data from eastern Cambodia between 1999 and 2007 and documented Eld’s Deer records from five of nine survey sites. However in three of these (Phnom Prich Wildlife Sanctuary, areas of Seima Protected Forest and adjacent Snoul Wildlife Sanctuary and unprotected forest close to Prey Khieu at the Mondulkiri-Stung Treng provincial border) recent (post-2008) and extensive habitat loss is likely to have resulted in subpopulation extirpation.

Recent robust distance-based line transect surveys in a number of protected areas which support, or supported, the species (Mondulkiri Protected Forest, Seima Protection Forest, Phnom Prich Wildlife Sanctuary, Preah Vihear Protected Forest and Kulen Promtep Wildlife Sanctuary) failed to detect sufficient Eld’s Deer for population estimation c.f. another globally threatened large ungulate in the landscape banteng Bos javancius (O’Kelly et al. 2012, Gray et al. 2013, S. Mahood pers. comm. 2014). 

Only the subpopulations in Mondulkiri Protected Forest (~50-75 individuals) and Kulen Promtep Wildlife Sanctuary/Preah Vihear Protected Forest (probably a similar size to that in Mondulkiri Protected Forest) are likely resident year-round within a relatively well-patrolled and secured protected area. Numbers in western Siem Pang, Stung Treng province may be higher than previously suspected (BirdLife International Cambodia 2012) but the subpopulation, of between 50-150 individuals, occurs at a site directly threatened through ongoing conversion to Economic Land Concessions. At Ang Trapaeng Thmor Sarus Crane Conservation Area, Banteay Meanchey province, the subpopulation of 30-50 individuals disperses out of the protected area into community forestry during the wet-season (S. Mahood pers. comm. 2014). 

R. e. thamin was still relatively widespread and abundant during the mid-1980s on the plains of central and northern Myanmar, where its range centred on the Irrawaddy Plain, including the Bago or Sittang Plain to the east. It was said to be present to the southeast, along the Thai border (Salter and Sayer 1986), and along the western border with Bangladesh (Lekagul and McNeely 1977), but these records are doubtful and a questionnaire in 1992 and surveys in 1997 could only find evidence for the species in the northeast (McShea et al. 2000). In 1992 a countrywide questionnaire was distributed by the then Wildlife Department of Myanmar, this resulted in reports of Eld’s Deer from 28 Myanmar townships, and 2,200 Eld’s Deer were estimated to remain within Myanmar, with the largest population (over 1,200 deer) in Chatthin Wildlife Sanctuary (Myint Aung 1994, McShea et al. 2000). Regular transect surveys in Chatthin Wildlife Sanctuary between 1983 and 1996 indicated a population decline of upwards of 40% (McShea et al. 2000), with a population estimated at about 500 deer in the latter years (Myint Aung pers. comm. 1996). More recent evidence indicates a continued decline at this site and the population is likely now to be considerably below 100 individuals (W.J. McShea in litt. 2014).

A nationwide survey of Myanmar in 1997 found evidence of Eld’s Deer within 23 of 24 townships surveyed, out of the 28 that were reported to contain Eld’s Deer in 1992. The four un-surveyed townships were considered very unlikely to still harbour deer because of the little remaining habitat within them (McShea et al. 2000). By 2003 a repeat of the 1992 surveys concluded that deer had disappeared from four townships and had declined in at least another four, but there were signs that in some townships populations were stable or even increasing (Myint Aung 2004). However, surveys in 2007 found Eld’s Deer in only 14 townships and had therefore seriously declined. Increases and decreases were in part put down to reforestation efforts and habitat loss respectively (Myint Aung 2004). More recent, anecdotal, assessment of habitat quality indicates considerable loss of lowland deciduous forest throughout central Myanmar in the last 10 years (W.J. McShea in litt. 2014). At Shwesettaw Wildlife Sanctuary, favourable habitat has been taken over by agriculture however more recent information suggests that the site may now hold the most significant Eld’s Deer population in the country with at least 200 individuals noted in 2004 (W.J. McShea in litt. 2014). 

Chatthin Wildlife Sanctuary was described in the 2008 assessment as “now the only viable population with nominal protection, and habitat currently appears more secure” however the assessors ominously noted that “protection efforts appear to be failing, at least partly reflecting changes in management. Since funding from the Smithsonian Institution ceased in 2003, the amount of patrolling and the Eld’s Deer population have decreased every year (W. McShea pers. comm. 2008); a causal link seems inescapable”. More recent, ad-hoc, observations support this conclusion and it is likely that Eld’s Deer populations in Chatthin Wildlife Sanctuary have declined >50% in the past 10 years. 

Two populations detected on the outskirts of Alaungdaw Kathapa National Park and Mahamyaing Wildlife Sanctuary were  never protected by inclusion in the  parks, and elsewhere in the country other populations and large blocks of suitable habitat have not been gazetted into the protected area system despite hopes that they would be (McShea et al. 2000, W. McShea pers. comm. 2008). 

In Lao PDR there are one or two known populations. One (of probably under 50 animals) is in Savannakhet province (central Lao PDR) and has been the focus of a community led species-specific conservation project, with regular subjective monitoring of the population (Johnson et al. 2004, A. Johnson pers. comm. 2007, T. Gray pers. comm. 2013). However this monitoring is not able to effectively estimate population size or trends.. In the late 1990s another small subpopulation, of probably the low dozens of animals, was found from Champasak Province, far south-western Lao PDR, in areas adjacent to the Dong Khanthung Provincial Protected Area, but there has been no recent re-evaluation of the site and it is quite plausible that the species has been hunted out there (Round 1998, Duckworth et al. 1999, A. Johnson pers. comm. 2007, R. J. Timmins pers. comm. 2008). It is unlikely, given the distribution of suitable habitat, the distribution of the human population, and the pervasive hunting culture in Lao PDR that any more significant populations of the species remain to be found (R.J. Timmins pers. obs.); lowland Savannakhet province was the only unprotected part of Lao PDR where in Duckworth et al. (1999: 41) recommended additional surveys of large mammals as likely to reveal new conservation priorities. One subpopulation was indeed found but since that was written, options for others have greatly declined due to extensive road-building, conversion of remaining dry forest habitat and assignment of much of the rest to plantation concessions (particularly on the western plains of the province) and continued extremely high levels of trade-driven large mammal hunting make the chances of any others remaining now very low (J.W. Duckworth in litt. 2008 from field assessment in late 2007).

Survival in Viet Nam is now very doubtful. Eld’s Deer was still reported by local inhabitants in the early 2000’s (e.g. as reported in Nguyen Xuan Dang and Nguyen Thi Thuy (2004), but field surveys of such areas have failed to find the species (Do Tuoc pers. comm. 2006). Perhaps a few animals remain along the border with Cambodia (Do Tuoc pers. comm. 2006), but repeated recent surveys of one of the more promising areas, Yok Don National Park, has not produced good evidence (Le Xuan Canh et al. 1997, Eames et al. 2004). The reported distributions given by Dang Huy Huynh (1990) and Ratajszczak (1991) were either overly optimistic and based on unverified evidence, or indicate a recent swift decline in the species in Viet Nam; probably both factors are responsible.

Continued presence of ancestral wild populations in Thailand is also now very unlikely. At best a few remnant individuals may survive or immigrate. The Thai Royal Forestry Department has a captive breeding programme for both R. e. thamin and R. e. eldii and there have been attempts at introduction of the former in two areas (where it was never a native subspecies); numbers living in a ‘wild state’ are in the low tens (Naris Bhumpakphan et al. 2004). 

Although once distributed in the tropical zone of southwest Yunnan and further east, the South China Eld’s Deer has long been extirpated (Smith and Xie 2008, Zeng et al. 2005). By the 1970s the only remaining Chinese populations were on Hainan and had declined to some 40 animals in Dong Fang and Bai Sha Counties, primarily due to poaching, from a reported 500 individuals in 1950s (Zeng et al. 2005). In 1976 two protected areas, the Datian Nature Reserve, and the Bangxi NR, West Hainan, were founded around the two last remaining isolated herds of deer, with 26 and 20 animals respectively (Song and Zeng 2004, Pang et al. 2003, Zeng et al. 2005). By 1981 the Bangxi NR population had been exterminated by poaching (Zeng et al. 2005). The animals in Datian NR were kept in fenced enclosures while the population grew, and at the current time the whole c. 13 km2 of the reserve is enclosed (Song 1996, Pang et al. 2003, Zeng et al. 2005). Initial problems with conservation efforts at Datian included encroachment of almost half its habitat by agriculture since its establishment, deer deaths through drought and overcrowding in small enclosures, and some poaching (Pang et al. 2003, Zeng et al. 2005). By 1991 the Chinese population had rebounded to 346 animals, of which 261 were within the Datian Nature Reserve (Yuan et al. 1993). By 2003 there were about 1,000 animals in Datian NR, and beginning in 1986 captive and semi-wild populations were established at other facilities, the total population in which was approximately 260 animals in 2003 (Song and Zeng 2004, Zeng et al. 2005). A semi-wild herd was founded once again in Bangxi NR, and by 2002 the population there was reportedly 115 animals (Zeng et al. 2005). In 2003 a third ‘wild’ herd was founded in Mihouling Reserve (Song and Zeng 2004, Zeng et al. 2005). 

In India, R. e. eldii was thought to be extinct in the early 1950s but was subsequently rediscovered. By 1975, the only remaining wild population had declined to about 14 animals in the swamps of Loktak Lake, Manipur (Ranjitsinh 1978). On this basis, a floating marsh on the southern end of Loktak Lake was gazetted in 1977 as the Keibul Lamjao National Park (Ranjitsinh 1978). During 2006-2008, Eld’s Deer presence was recorded in a 21.5 - 22.7 km2 area of the Keibul Lamjao National Park. Higher dung density was recorded from >9.0 ± 0.18 km2 area of the Park. The point count method used for population monitoring revealed the estimated density of 4.04, 4.08 and 4.05 individuals per km2 during 2006, 2007 and 2008 respectively, with a minimum of 2.97 individual per km2 and maximum of 6.01 individuals per km2 at 95% confidence level. This yields the estimated mean population size as 91, 88 and 92 individuals during 2006, 2007 and 2008 respectively, with a minimum of 60 and maximum of 136 Sangai at 95% confidence level. This indicates that the population of Sangai in the Park is more or less stable (Hussain et al. 2009). 

Current Population Trend:Decreasing
Additional data:
Population severely fragmented:Yes

Habitat and Ecology [top]

Habitat and Ecology:

Populations in Lao PDR, Viet Nam and Cambodia seems to have occurred in a variety of primarily open, grass dominated habitats. Most evidence of presence comes from Deciduous Dipterocarp Forests which primarily occur in the highly monsoonal areas of the Mekong plains (Wharton 1957, Tordoff et al. 2005, R.J. Timmins pers. comm. 2008), but historical populations known from, for instance, the Nakai and Bolaven plateaux of Lao PDR appear to have used a mosaic of small grasslands and wetlands amongst pine, semi-evergreen and other forest types, and those known from the Dalat and Kirirom plateaux would seemingly have occurred in more extensive pine/savanna habitats (R.J. Timmins pers. comm. 2008). The species may also have occurred in northern Lao PDR, where suitable habitat is localised to a few plains amid the generally unsuitable rugged densely forested terrain but no conclusive records have been traced (Duckworth et al. 1999), and would have presumably inhabited Mixed Deciduous Forests and grasslands of anthropogenic origin, (R.J. Timmins pers. comm. 2008). Populations in deciduous Dipterocarp Forest appear to favour open-canopy formations, with grass dominated understory, especially areas with extensive grassland patches, and avoid closed-canopy formations where small deciduous bamboos predominate in the understory (Timmins and Ou 2001, Timmins et al. 2003, Tordoff et al. 2005, R.J. Timmins pers. comm. 2008, Gray et al. 2012, T. Gray pers. comm. 2013). Given the highly seasonal nature of such forest areas, permanent wetlands, usually in the form of forest pools or stream bed pools, are likely to be very significant to the species and the densities of animals that a given area can support (R.J. Timmins pers. comm. 2008; T. Gray pers. comm. 2013). Despite suggestions to the contrary in some sources, there is no evidence that Eld’s Deer in these countries are particularly wetland associated, nor is there evidence that the species reached high densities in floodplain tall grasslands (contrary to the case with hog deer) (R.J. Timmins pers. comm. 2008).

The grasslands that the species appears often to associate with are favoured over forest for conversion to rice paddies, and the paddies likewise appear attractive to the deer (T. Gray pers. comm. 2013).

Males appear to be fond of wallowing. Anecdotal evidence suggests that deer do not make substantial movements and tend to remain year round within relatively small areas (R.J. Timmins pers. comm. 2008). At Ang Trapaeng Thmor Conservation Area deer are forced to disperse, during the wet-season, from flooded grassland and agricultural areas around a reservoir where breeding occurs, into adjacent areas of decidious Dipterocarp Forest (S. Mahood pers. comm. 2013). Lekagul and McNeely (1988) suggested that Eld’s Deer had been driven into drier areas by hunting and habitat destruction. However, this is clearly not the case in Cambodia where historically Eld’s Deer were considered one of the most abundant species in the open seasonally very dry forests of the north and east (Wharton 1957).

The Loktak lake population in Manipur, India, inhabits an area of floating marsh called locally ‘phumdi’ (Singh 1983, 2004). This population has adaptations of the feet which are thought to help the animals move easily in their marshland habitat (Pocock 1943), but Pocock (1943) speculated that elsewhere in north-east India Eld’s Deer would also have occupied drier plains. 

In Myanmar most Eld’s Deer occur in indaing forest, which is usually dominated by the tree Dipterocarpus tuberculatus, and is structurally and ecologically fairly equivalent to the Deciduous Dipterocarp Forest of Indochina and Thailand. There are two other types of deciduous forests used by the deer in Myanmar, dry (thandahat), and mixed (teak). All three forest types receive 100-200 cm of rainfall a year (Prescott 1987; Bronson 1989; McShea et al. 1999, 2001; Myint Aung et al. 2001). Pristine habitat is now absent within the Myanmar range of Eld’s Deer and all populations use habitats at various stages of secondary succession (McShea et al. 2005).

The ecology of animals in Myanmar is likely to be similar to those in Indochina and Thailand reflecting the similarities in habitat, with dry-season movement closely correlated with the locations of water sources (Prescott 1987; McShea et al. 1999, 2001). At the Hlawga wildlife park just outside Yangon, Myanmar, many species of Myanmar’s native wildlife have been introduced. In contrast to Hog Deer, Sambar and Northern Red Muntjac, which have all increased to good populations, Eld’s Deer has failed to establish itself within this small fenced area. This is attributed by staff, including a past veterinarian, to the area being too humid (it is said to be outside the native range of Eld’s Deer) although this has not been confirmed.

The typical habitat of ‘Eld’s Deer in Hainan Island is scrubland and dry grassland together with sparse trees in hills below 200 m asl in altitude (Zeng et al. 2005).

Eld’s Deer feeds on grass and some browse and also take fallen fruits and flowers, and reportedly can live without water for several days. Eld’s Deer regularly visits salt licks. Stags are generally solitary except during the rut, while hinds congregate throughout most of the year (Gee 1961, Myint Aung pers. comm. 1996). Wharton (1957) recorded large herds in Cambodia in the 1950s, and Lekagul and McNeely (1988) stated that, prior to hunting reductions, herds of over 50 formed. In Keibul Lamjao National Park, R. e. eldii is thought to move from the ‘phumdi’ to island hillocks during periods of flooding (Green 1990). In China, the rut is during February-June, with a single fawn born from September to January. In India, calving occurs from mid-October to the end of December. Gestation period is between 237 and 240 days, and sexual maturity is reached at approximately 1.5-2.0 years (Wemmer and Grodinsky 1988).

Systems:Terrestrial; Freshwater
Generation Length (years):5

Use and Trade [top]

Use and Trade: Eld's Deer is hunted for food and other purposes. There are many captive animals, the uses of these other than for breeding stock are unknown.

Threats [top]

Major Threat(s):

In Cambodia, Lao PDR and Viet Nam the most obvious threat to Eld’s Deer is hunting, which in addition to local consumption of meat is driven by a thriving and probably increasing trade in bushmeat, a national, regional and East Asian market for traditional medicinal products derived from the species, and a regional international market for trophy antlers (Duckworth et al. 1999, Timmins and Ou 2001, Tordoff et al. 2005, Zeng et al. 2005). However since 2010 large-scale habitat loss and conversion of Deciduous Dipterocarp Forest for Economic and Social Land Concessions, which also increased hunting pressure, has become an equally significant threat in Cambodia. In addition the highly fragmented nature and small population size of the remaining subpopulations makes the species’ perhaps vulnerable to small population threats.

The influence of traditional medicinal trade is uncertain, but may be very significant as products derived from the species are reportedly more valuable than are those from other deer (Zeng et al. 2005). Some hunting in Cambodia is probably also driven by a demand for captive animals especially from zoos and menageries in Thailand and Cambodia (Salter and Sayer 1986, R.J. Timmins pers. comm. 2008). The species is apparently easy to hunt compared with other sympatric deer, and fawns are likely to be very vulnerable to dogs which almost always accompany human parties during forest visits, even when the visits are not for hunting (Tordoff et al. 2005, R.J. Timmins pers. comm. 2008). Predation of fawns by domestic dogs, which are ubiquitous within dry forests in lowland Indochina, has been identified as a threat to the Savannakhet subpopulation in Lao PDR (P. Vongkhamheng pers. comm. 2013) and may also impact the scattered Cambodian subpopulations particularly those outside the cores of protected areas. The effects of hunting have been exacerbated by forest loss and fragmentation, which is rapidly accelerating with human population in-migration, infrastructural developments (especially roads), commercial agricultural expansion, economic land speculation and mineral extraction. Selective logging was initially one of the main driving forces, but it is now of relatively minor concern (Tordoff et al. 2005, R.J. Timmins pers. comm. 2008). Human in-migration and subsequent agricultural encroachment into forest areas tends to concentrate on those habitats most used by Eld’s Deer, and thus the species has suffered more than most from hunting (R.J. Timmins pers. comm. 2008, Tordoff et al. 2005). In-migration is also a commonly associated with land concessions in Cambodia. Indeed the loss of considerable (~500 km2) Eld’s Deer habitat in Preah Vihear province in 2011-12 was associated with a Social Land Concession given to military families. As an inhabitant of relatively open habitat through which travel and transport are easy, it is also likely to have been more heavily affected by a given level of hunting effort compared with species of rugged, dense hill evergreen forest; a similar scenario has been postulated for Jungle Cat Felis chaus (Duckworth et al. 2005, R.J. Timmins pers. comm. 2008).

Probably the most significant challenge to conserving the species in Lao PDR, Cambodia and Viet Nam is the uncertainty involved with long-term protected-area based conservation management. No protected areas within Cambodia are safe from conversion to other land-uses. Protected areas, even those that at present have relatively active and effective management, face an uncertain future with the possibility of excision of conservation status largely for land concessions, the lack of long-term security in external funding adequate to maintain high standards of management, fluctuations in political support necessary to uphold high protection standards and the consequential difficulties of maintaining a motivated and well-trained staff.

Protected areas, primarily those along the tri-border area of Thailand where it adjoins both Lao PDR and Cambodia, and the Huai Kha Khaeng WS, were unable to prevent the decline and likely extirpation of Eld’s Deer from the wild in Thailand (see Bhumpakphan et al. 2004). This decline was likely to have been driven by much the same reasons as in Indochina. If any Eld’s Deer do remain in the wild there, it seems unlikely that they will ever recover unassisted. There are few data on the introduced populations of R. e. thamin to non-native areas (see Bhumpakphan et al. 2004).

Threats to the species in Myanmar appear to be similar to those in Indochina, with perhaps more emphasis on exploitation for meat (Salter and Sayer 1986, Myint Aung pers. comm. 1997).

Habitat loss in some range areas is still ongoing (Myint Aung 2004) and Koy et al. (2005) found that ‘patterns of percentage tree canopy-cover were negatively correlated with human population density, suggesting further threats to Eld's Deer populations as the human population continues to grow’.

A support programme for the main site, Chatthin Wildlife Sanctuary, had an encouraging start but following cessation of external funding the population is now in decline (see Population), while other protected areas in the country either failed to include appropriate habitat for the species (e.g. Alaungdaw Kathapa National Park) or failed to protect the habitat even within the protected area (e.g. Shwesettaw Wildlife Sanctuary).

Overall, the challenges of generating functional protected areas which will sustain Eld’s Deer are similar to, and under current conditions even more daunting than, those outlined for Cambodia, Lao PDR and Viet Nam (above). In general, protected areas in Myanmar are themselves highly threatened by major shortfalls in funding and political will (Rao et al. 2002).

The population on Hainan faces an uncertain future as a wild animal without hands-on management, because protected area management has not been effective in preventing poaching (see Pang et al. 2003, Zeng et al. 2005). Loss of suitable habitat has been extensive and is continuing, but large enough areas probably remain for further population expansion, provided that herds in such situations could be adequately protected from poaching (see Zeng et al. 2005). Genetic analyses of the population suggest that there is low diversity resulting from a population bottleneck, and this could in the future threaten the population’s viability (Pang et al. 2003, Balakrishnan et al. 2003).

Indian populations of Eld’s Deer declined due to some combination of hunting and habitat loss. Even at the Keibul Lamjao National Park, the habitats of the deer have been encroached for grazing, cultivation, and fish farming (Green 1990), but this seems to be mainly now under control (Singh 2004). This population is now most threatened by a hydro-electric project in Loktak Lake which maintains unnaturally high water levels during the dry season and has changed water flow patterns and water quality in the lake (Singh 2004). These in turn appear to be affecting the ecology of the Keibul Lamjao National Park floating marsh (Singh 2004, Sanjit et al. 2005). Floods could also seriously affect the population, which has no high ground to which it can easily escape (Singh 2004). There may also be the threat of low genetic diversity resulting from the effect of a very small founder population (Balakrishnan et al. 2004) and as a small isolated population it must also be considered at risk from disease transfer from domestic livestock, and potentially other factors.

Eld’s Deer readily grazes on rice and some other agricultural products (McShea and Myint Aung 2001). This provides some potential for human-wildlife conflict, but under current conditions populations seem to be too low for this to be a serious problem (e.g. at the Chonbuly district population, Savannakhet province, Lao PDR; J.W. Duckworth in litt. 2008). Retributory killing may become more of a threat if populations are successfully rebuilt in areas close to agriculture.

Conservation Actions [top]

Conservation Actions: This species is listed on CITES Appendix I. Although most Cambodian Eld’s Deer are within protected areas few occur within government approved Core Zones (Timmins et al. 2003, McShea et al. 2005, Tordoff et al. 2005, Timmins 2006). The recent loss, or substantial decline of subpopulations in, and around, Seima Protected Forest, Phnom Prich and Snoul Wildlife Sanctuaries, and O’Yadao Protected Forest due to conversion to land concessions largely occurred because these subpopulations were on the edge of protected areas, close to villages, and in areas where conversion to other land-uses was difficult to prevent.Conservation management of the Kulen Wildlife Sanctuary, Preah Vihear Protection Forest, and, particularly, Ang Trapaeng Thmor Sarus Crane Conservation Area and Mondulkiri Protected Forest may be stabilising and perhaps even increasing Eld’s Deer populations, through externally funded conservation management projects supported by the Wildlife Conservation Society and The World Wide Fund for Nature (WWF unpublished data, WCS unpublished data, R.J. Timmins pers. comm. 2008, T. Gray pers. comm. 2013, S. Mahood pers. comm. 2013). However evidence of increasing Eld’s Deer populations does not exist and recent intensive line-transects surveys have not detected sufficient individuals for robust population size estimation. These five areas cover well over 3,000 km2 of relatively suitable Eld’s Deer habitat, and thus the most pressing conservation need is the continued support and consolidation of these protected areas. Only once this is in place would it be sensible to divert resources to protect Eld’s Deer in further areas of Cambodia currently with little to no active protection. However the intensities of law enforcement within these sites is highly variable and dependent upon both external non-governmental financial and technical support and political buy-in from governments. For example the temporary removal of provincial police from supporting patrolling activities in Mondulkiri Protected Forest in 2011 by provincial authorities resulted in at least one documented Eld’s Deer poaching event and a considerable influx of general illegal activity across the protected area.

An additional conservation action within the core zone of Mondulkiri Protected Forest is the artificial deepening of natural waterholes (trapaeng in Khmer) to ensure year-round water availability, which is also planned for Preah Vihear Protected Forest and Kulen Promtep Wildlife Sanctuary (S. Mahood pers. comm.). Research has indicated the majority of trapaeng are dry in the height of the dry-season and trapaeng deepening has been demonstrated to maintain enhance water retention and provide dry-season water access to Eld’s Deer and other threatened species (T. Gray pers. comm. 2014 and unpublished manuscript).

The central Lao population in Chonbuly District, Savannakhet Province, is under nominal protection in a roughly 200 km2 provincial protected area specifically designated for the species (Johnson et al. 2004). The area had an ongoing conservation management project supported by the Wildlife Conservation Society (Johnson et al. 2004) which since 2009 has been resumed by WWF with support of the Critical Ecosystem Partnership Fund (T. Gray pers. comm. 2014). The single southern Lao population found during extensive surveys in the 1990s was small and inhabited a mosaic of farmland amidst forest, adjacent to a subsequently declared provincial protected area (Round 1998). Attempts to upgrade the provincial protected area to national status have failed (A. Johnson pers. comm. 2007)..

In Thailand the protected area system failed to prevent the species' effective national extinction some years ago. Therefore, recent conservation efforts there have focused on the captive breeding of large numbers of R. e. thamin (see Bhumpakphan et al. 2004), which is not, however, native to most of Thailand. Attempts to introduce R. e. thamin to non-native areas have had limited success, although there is a residual herd at Phu Khieo Wildlife Sanctuary and Propagation Station (Bhumpakphan et al. 2004). Forty-five individuals were reintroduced into Huai Kha Khaeng WS and approximately 20 deer to Wang Lor Wildlife Sanctuary but then the programme was discontinued (W. McShea pers. comm. 2014). R. e. siamensis was the subject of an abortive Smithsonian Institution reintroduction program initiated in 1985. By 1989, progress was limited to construction of holding facilities at Phu Khieo Wildlife Sanctuary and Propagation Station. As with other range states the most pressing conservation measures seem to be strengthening protected area management in those areas that cover the species' former range, so that reintroduction might be possible in the future, jointly with measures to align all stakeholders to ensure that introduction programmes do not create herds with a mix of R. e. siamensis and R. e. thamin ancestry.

The Hainan population is now highly managed with most of the population in Datian NR, and other animals in Bangxi NR and Mihouling Reserve, and other captive facilities (Zeng et al. 2005). The species has been the subject of various avenues of research, for instance a population viability analysis was undertaken to examine demographic and environmental (drought) challenges to the two enclosed populations at the Hainan Datian Nature Reserve (Song 1996), with other research by Yuan et al. (1993) and Song (1993) (see also Zeng et al. 2005). But, the most important conservation measure needed appears to be strengthening of the protected area system so that deer can be re-established in a wild state without danger of poaching or habitat encroachment (see Zeng et al. 2005).

India held 97 captive animals in 15 zoos in December 1992, a slight decline from over 100 in the mid-1980s (Decoux 1993); by 1994, 14 zoos held 107 animals (Sharma 1994). The population is probably inbred: all reportedly are descended from two founder pairs (Walker and Marimuthu 1991, see also Balakrishnan et al. 2003). The 40 km2 Keibul Lamjao National Park was gazetted in 1977 specifically to protect R. e. eldii (Ranjitsinh 1978). Subsequently projects at the park have raised public awareness, and local support has been developed for conserving the endemic Manipur subspecies, and largely halted encroachment of the species habitat (Singh 2004). Status surveys of R. e. eldii have been carried out annually in Keibul Lamjao National Park since 1975 (Ranjitsinh 1996, Singh 2004), and research has been undertaken by Singh (1983, 2004). A Wildlife Institute of India proposal in the 1980s to establish a second free-ranging population in Assam (Khan et al. 1993) was not implemented. Conservation needs are essentially mitigating detrimental effects of the hydropower project on the park, strengthening the protected area management of the park (e.g. through even further improvement of local relations and capacity building), increasing the park’s area to meet the needs of deer through appropriate research and potentially establishing further wild populations in other areas.

In Myanmar, Chatthin Wildlife Sanctuary and Shwesettaw Wildlife Sanctuary were established specifically to protect R. e. thamin (Salter and Sayer 1986), but little management has been undertaken and despite promising initial efforts, management effectiveness appears to be decreasing (Myint Aung 1990, W.J. McShea pers. comm. 2008). Deer were found on the outskirts of two other protected areas  Alaungdaw Kathapa National Park and Mahamyaing Wildlife Sanctuary, but protection efforts were never extended to cover the appropriate area, and the majority of the remnant area occupied by the species are likely to be outside protected areas (McShea et al. 2000, W. McShea pers. comm. 2008). A number of reintroductions have taken place into enclosed sites such as Hlawga Wildlife Park, using animals from Rangoon Zoo and the wild. In 1995, an ecological study of radio-collared R. e. thamin was initiated in Chatthin Wildlife Sanctuary by the Smithsonian Institution, and a community education project commenced later that year to raise local awareness of the deer and the wildlife sanctuary (Wemmer 1995). The Wildlife Division surveys the population annually using a basic line transect method. Conservation measures needed were recently assessed to include extending the protected areas network (McShea et al. 2000) but in the interim the most pressing needs seem to be to prevent further deterioration at Chatthin Wildlife Sanctuary and to salvage the Shwesettaw Wildlife Sanctuary, if this is possible.

McShea et al. (2005) argued that "only Cambodia, with 11% suitable forest protected, has placed sufficient dry dipterocarp forest under protected status. Other Southeast Asia countries have not recognized dry dipterocarp forest as a significant ecotype worthy of conservation status". It is certainly true that this forest type has been seen as a low priority in the conservation planning of all range states, but consideration that a country has placed 'sufficient' of any habitat type under protected status is subjective and a variety of measures can be used. In this case, 'sufficiency' was judged on the basis of proportion of a country's total suitable habitat that has been nominally protected. An alternative would be to consider factors like the actual amount of protected habitat, and whether this is enough to represent the range of biotic variation within the country; whether such habitat is in large enough blocks to remain ecologically functional into the long term, and whether protection is largely nominal or is genuinely effective. The last dichotomy is likely to be the chief determinant of whether Eld's deer will survive. Considering that no range states yet have existing protected areas which have secured the species on a long-term footing (although there are promising developments in several countries), and considering the speed with which populations can decrease, priority is necessary at present to concentrate most conservation actions for Eld’s Deer on securing existing protected areas for key populations which have real potential for success. This has become increasingly urgent given the accelerating threats to lowland deciduous dipterocarp forest in Cambodia both outside, and within, protected areas. Determining this potential will reflect situational factors as much or more than ‘traditional’ biological factors such as current Eld’s Deer status within them. Eld’s Deer could potentially persist in habitat mosaics of forest and agriculture, as they still do in some areas of Myanmar and Cambodia (McShea et al. 2000, T. D. Evans pers. comm. 2007), but cultural predisposition to hunting and competing land uses make it unlikely that poaching can be controlled, or habitat management developed, without the context of a protected area, in most range countries (India and perhaps Myanmar being the most likely exceptions).

There are large captive populations of the species, estimated in 2003 to number 180 R. e. eldii, 1,100 R. e. thamin, 23 R. e. siamensis (non-Hainan stock) and 280 R. e. siamensis (Hainan stock), but most captive groups are not managed with conservation in mind (Siriaroonrat 2004). There is some scope for using these animals in reintroduction programmes, particularly in Thailand where Eld’s Deer is nationally extinct yet the country is now probably in ‘the best financial and administrative position’ of all range states to conserve landscape-scale field populations of the species (McShea et al. 2005).

Citation: Gray, T.N.E., Brook, S.M., McShea, W.J., Mahood, S., Ranjitsingh, M.K., Miyunt, A., Hussain, S.A. & Timmins, R. 2015. Rucervus eldii. The IUCN Red List of Threatened Species 2015: e.T4265A22166803. . Downloaded on 26 September 2018.
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