Scientific Name: Rucervus eldii
Species Authority: (M'Clelland, 1842)
Common Name(s):
English – Eld's Deer, Thamin, Brow-antlered Deer
French – Cerf D'Eld
Spanish – Ciervo De Elde
Synonym(s):
Cervus 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. Groves (2006) pointed out that, by implication under a phylogenetic species concept, the taxon siamensis should probably be recognized as specifically distinct from R. eldii, and urged for a formal study of this. 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. nd).
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 population 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: 2008
Date Assessed: 2008-06-30
Assessor(s): Timmins, R.J. & Duckworth, J.W.
Reviewer(s): Black, P.A. & Gonzalez, S. (Deer Red List Authority)
Justification:
The species is considered EN 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). 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 populations. This population decline is due primarily to hunting, especially of Cambodian/Lao/Viet Namese stocks where declines probably exceed 90%, primarily in the past, although they are ongoing and are expected to continue into the short-term future (until all animals are lost from outside those protected areas which succeed in stabilising Eld's deer populations). The Myanmar population also declined over the same period, perhaps not as dramatically, and is still declining. The Manipur population is increasing, but its small size (under 250) and threatened habitat in a single small protected area leave little cause for long-term optimism. The resultant categorization as EN is thus a compromise taking into account the widely different statuses and conservation trends in the geographically isolated and distinct populations of this species, but with more weight on remnant wild populations, rather than those in managed or introduced situations.
History:
1996 – Vulnerable (Baillie and Groombridge 1996)
1996 – Vulnerable
1996 – Critically Endangered
1994 – Vulnerable (Groombridge 1994)
1990 – Vulnerable (IUCN 1990)
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 localised 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:
Native:
Cambodia; China; India; Lao People's Democratic Republic; Myanmar
Possibly extinct:
Thailand; Viet Nam
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 Eld's deer still occurs over a relatively wide area, although localised within this, surviving as small remnant groups in the lowland forests of the north and east. The total population could well be several thousand animals in a forest area that probably exceeds 20,000 km², but densities are extremely low (Tordoff et al. 2005; R.J. Timmins pers. comm. 2008). Survey work in appropriate habitat in the last decade has detected populations 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 population in the Phnom Aural area which persisted until at least the late 1990s (Henshaw et al. 2002; Tordoff et al. 2005). Declines since the late 1950s, when large herds were still readily seen (Wharton 1957), have been dramatic. Even in the last decade or so, the species has declined by 90% or more, given comparisons of aerial counts in 1994 with ground survey results from 1998 to the present (Olivier and Woodford 1994; Timmins and Ou 2001; Timmins et al. 2003; R.J Timmins pers. comm. 2008). Declines are likely to continue into the future, especially as most remnant groups and animals live either outside protected areas, or in protected areas with little active management. At least a 50% decline in the next 10-15 years seems likely. Populations in the Srepok Wilderness Area, the Siema Biodiversity Conservation Area, the Preah Vihear Protection Forest, Ang Trapeang Thmor Conservation Area and Kulen Wildlife Sanctuary are likely to remain stable and may potentially increase due to ongoing externally funded conservation area management projects (WWF unpublished data; WCS unpublished data; R. J. Timmins pers. comm. 2008).
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). 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 unsurveyed 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 leas
đang được dịch, vui lòng đợi..
