| Citation |
Timmins, R.J., Coudrat, C.N.Z., Duckworth, J.W., Gray, T.N.E., Robichaud, W., Willcox, D.H.A., Long, B. & Roberton, S. 2016. Chrotogale owstoni. The IUCN Red List of Threatened Species 2016: e.T4806A45196929. http://dx.doi.org/10.2305/IUCN.UK.2016-1.RLTS.T4806A45196929.en. Downloaded on 22 August 2019. |
Description |
RANGE DESCRIPTION
Owstons Civet is known to occur across a wide latitudinal range of both eastern Lao PDR (Sivilay et al. 2011, Coudrat et al. 2014, Gray et al. 2014b) and Viet Nam (Roberton 2007, Dang and Le 2010), and in a small area of southernmost China, possibly only in Hekou, Luchun and Jinping counties of Yunnan province (Wang Ying-xiang 2003) but perhaps also in adjacent Guangxi province (Lau et al. 2010). It has not been found west of the Mekong river (Corbet and Hill 1992) and indeed occurrence in Lao PDR is restricted largely to the easternmost areas that have similarities in climate to Viet Nam. The range may also potentially extend into easternmost Cambodia: two individuals seen in the Phnom Tamao zoo (Phnom Penh) collection of stuffed mounts in the late 1990s were unlikely to have originated outside Cambodia (C.M. Poole pers. comm. to Dang and Le 2010). However, extensive surveys in Cambodias eastern provinces have not found the species (e.g., Gray et al. 2014a, E.H.B. Pollard pers. comm. 2012). Perhaps the most likely area of Cambodia, eastern Virachey National Park, remains very little camera-trapped. Suitable methodology (camera-trapping and/or spotlighting) has been applied widely enough in the southern half of Lao PDR to be confident the species is entirely or largely restricted to the east in the south and latitudinal centre; capable searches have been less widespread in the northern highlands.
Records come from the range 100-2,600 m, but, particularly west of the Annamites, only a subset of this full range is likely to be occupied in any given area (see Habitats and ecology).
HABITAT AND ECOLOGY
Owston’s Civet occurs in a variety of habitats, all within evergreen biomes, linked by the common feature of a non-harsh dry season. It is, or was, much more widely spread in Viet Nam than in Lao PDR, reflecting the much larger area of Viet Nam with significant humidity in the driest months (i.e., lacking a harsh dry season). The pattern of locality records in Lao PDR where the species is evidently naturally localised quite clearly shows that the species has a narrow habitat usage. Areas with a non-harsh dry season in Lao PDR are restricted (Timmins and Trinh 2001). The areas providing high encounter rates of Owstons Civet in Lao PDR are adjacent to low sections of the Annamite spine (the north-south mountain range forming much of the international border between Lao PDR and Viet Nam) that allow moisture-bearing winds from Viet Nam during Lao PDRs dry season, which in the rest of the country is harsh at lower and mid altitudes (Timmins and Trinh 2001, Duckworth et al. 2010, Sivilay et al. 2011, Coudrat et al. 2014). Many other evergreen forest survey areas across the country lack records, despite the use therein of methods suitable to find the species, at adequate intensities, and the finding of multiple hunting-sensitive ground-dwelling mammals, It is essentially absent from the predominant evergreen forest types of Lao PDR, lowland, mid-elevation and lower montane semi-evergreen (dry evergreen) and lower montane forests. This is based on spotlighting in several survey areas supporting these forest types in the early - mid 1990s (Duckworth 1997) and on camera-trapping in the 21st century in Phou Sithon, Nakai-Nam Theun National Biodiversity Conservation Area (NBCA), Laving-Laveun NBCA, Nam Kading NBCA, Phou Chomvoy Provincial Protected Area and Xe Sap NBCA (Duckworth et al. 2010, Coudrat et al. 2014, Gray et al. 2014b, R. J. Timmins pers. comm. 2014); the hunting intensity in all of these at the time of camera-trapping was equivalent to Pu Mat before (sometimes well before) 1998, about when the species was still readily detected by camera-traps. It is evidently locally present in Lao PDR below 1,000 m where wet evergreen forest occurs, but the absence of records from Laving-Laveun NBCA, which holds various other wet evergreen forest species, suggests that Owstons Civet is particularly sensitive to climatic conditions. It also occurs in montane evergreen forest (over 1,000 m), but is probably equally restricted by climatic conditions in its geographic and altitudinal range. Montane areas with wet climates, such as various high peaks in eastern parts of Lao PDR, appear to support the species over a relatively wide range (e.g., Xe Sap NBCA; Gray et al. 2014b), whilst peaks further west (greater rain-shadowing during the winter) appear to support more localised populations (e.g. Nam Et-Phou Louey NBCA; Johnson et al. 2009). Wet evergreen forest is, or was, far more widespread in Viet Nam than in Lao PDR, but it is not universal. The strong evidence from Lao PDR for climatic sensitivity of Owstons Civet suggests that some Viet Namese evergreen forests will hold the species sparsely or not at all (those in a rain-shadow).
In the Annamite wet evergreen forest of Lao PDR, Owstons Civet has been recorded as high as suitable survey has occurred (1,500 m; Gray et al. 2014b). The few records from Lao PDRs northern highlands, mostly imprecisely located (barring that in Johnson et al. 2009), are likely to come from higher altitudes where the colder temperatures ameliorate the low dry-season rainfall. Thus, in Lao PDR Owstons Civet is likely to occur mostly in hill and montane altitudes, although there are credible reports from as low as 550 m (Gray et al. 2014b), whereas in Viet Nam the species has a wide altitudinal range, right down to the plains and up to 2,600 m (Van Ban district, Lao Kay province, in 2002; S. Swan pers. comm. 2014). Recent camera-trap records at Mu Cang Chai and Muong La, in the northern highlands of Viet Nam, come from altitudes of 1,722-2,444 m a.s.l.; there was very little survey effort below 1,700 m (B.M. Rawson pers, comm. 2014).
Captive animals in both Viet Nam and the U.K. relish earthworms (J. Meek pers. comm. 2014, D.H.A. Willcox pers. comm. 2014) and the speciess skull and dentition suggest an invertebrate diet (Thomas 1927). An earthworm-dominated diet would explain the tight linkage with year-round humidity, given that in the parts of Lao PDR with a harsh dry season earthworms are not accessible during that season. This remains purely speculative, especially given that the component of Owstons Civet range south of the northern highlands resembles that of various other species unlikely to depend directly on access to earthworms, e.g. Annamite Striped Rabbit Nesolagus timminsi and Saola Pseudoryx nghetinhensis.
Suitable forests, in Viet Nam at least, include some on limestone and some dominated by bamboo (Roberton 2007). There are indications from Lao PDR of occurrence in degraded and edge habitat such as banana gardens (King 2002), but these remain to be confirmed. The lack of records from deciduous forest surely reflects the genuine pattern of occurrence.
Owstons Civet has not been studied in the field, but camera-trapping indicates that it is nocturnal, largely solitary and presumably largely active at ground level (e.g., Coudrat et al. 2014), although there is at least one record of a wild animal 3 m up a tree (Dang and Le 2010). The species climbs well in captivity (D.H.A. Willcox pers. comm. 2014).
THREATS
Lao PDR and Viet Nam, the two countries holding most of the geographic range of Owstons Civet, have among the highest levels of non-specific mammal hunting in the world. For many decades hunting with projectiles, dogs, and traps fabricated from local plant materials has been very high, for largely local use. From the late 1980s, rising throughout the 1990s, 2000s and into the 2010s, rapidly increasing affluence of Chinese and Viet Namese consumers and, to a lesser extent, those in Lao PDR has fuelled an explosive rise in urban demand for wildlife meat, including civets (e.g., Bell et al. 2004). In Viet Nam “the free market economy has resulted in feverish periods of trade in wild species nationwide, with negative impacts on biodiversity” (Government of the Socialist Republic of Viet Nam 2004). In Lao PDR, the same situation has developed, largely for export rather than in-country consumption. This demand has resulted in levels of snaring probably unprecedented anywhere in the world, using durable materials (metal) linked by brushwood drift-fences. These are evidently extremely efficient in extirpating mobile ground-dwelling mammals of civet size (e.g., Coudrat et al. 2014); some areas of little-degraded forest now support negligible densities of ground-dwelling mammals of this size class and above (Willcox et al. 2014).
Although such trade-driven off-take of large mammals from protected areas and such wildlife trade is unambiguously illegal in both Lao PDR and Viet Nam, enforcement is uneven and the large profits to be made hamper effective resolution of the problem. In parts of Lao PDR, trade prices for wild meat are so high and wild stocks so depleted that severe dietary problems are evident among rural hill people (i.e., those without access rights to productive fisheries) (Krahn and Johnson 2007). There is no reason to expect these hunting levels to decline until the wildlife species affected have been hunted out; larger species such as big cats Panthera, wild cattle Bos and Sambar Rusa unicolor are already widely extirpated in Viet Nam and Lao PDR (R.J. Timmins pers. comm. 2014), yet hunting continues. Some Viet Namese areas camera-trapped and discussed by Willcox et al. (2014) were almost bereft of any ground-dwelling mammals or birds bigger than rats. This is the plausible end-point for most areas holding Owstons Civet.
By contrast, Owstons Civet seems to be fairly resilient to long-standing hunting methods and intensities, judging by the numbers that were and still are camera-trapped in in Viet Nams northern highlands (Swan and OReilly 2004, S. Swan pers. comm. 2004, B.M. Rawson pers. comm. 2014). In contrast to Owstons Civet, many other hunting-sensitive species in these areas were or are already extirpated or reduced to numbers so low as to evade detection. This area has no or negligible trade-driven operation of metal snares in long lines; this lack is typical of Hmong-dominated northern highland areas (J. Tordoff pers. comm. 2014). Most hunting for mammals of civet-size and over in these areas is active, with projectiles and with dogs, rather than by passive trapping; and it is by day (B. Long pers comm. 2014). The nocturnal, solitary, generally inconspicuous habits of Owstons Civet evidently facilitate its survival in such areas; its dens must be in areas not readily found by dogs.
Habitat loss, degradation and fragmentation have affected large areas of Owston’s Civet range (Schreiber et al. 1989), particularly in Viet Nam and increasingly in Lao PDR. Habitat fragmentation magnifies the impact of hunting on populations, particularly when roads are built into areas of, until then, limited accessibility. Vehicle access makes the harvest of a whole host of mid-price marketable materials such as civet meat economically viable where previously the labour investment of carrying heavy loads long distances restrained off-take in those areas to high-value products and what was required for living off the land during the process. An ongoing massive expansion of the road system in Lao PDR, in part related to large infrastructure construction such as dams and mines (e.g., Sivilay et al. 2011, W.G. Robichaud pers. comm. 2014), is likely to bring most of the Lao areas holding Owstons Civet within close-enough range of vehicle access that general wildlife meat extraction is economically feasible. This is already the case for most of the Viet Namese areas.
The exceptions to this grim assessment include karst massifs (into which road building is rarely economically viable), montane areas inhabited by people who disdain snaring, and any protected areas which develop effective enough management regimes before the species is extirpated. While there are Owstons Civet records form karst, densities within such landscapes are unknown, as is the degree to which the species depends upon tall forests there (themselves rather patchy in occurrence in karst landscapes). The extent to which industrial snaring will spread into hill areas already largely depleted of animals larger than civets (by day-time shooting and hunting with dogs), notably large areas of the northern highlands, is unclear; if some such areas do not start to deploy it (for various reasons, such as ongoing remoteness from road networks, or the cultural predispositions of the inhabitants), these areas will also be important havens to Owstons Civet.
The adaptability of Owstons Civet to non-hunted degraded and fragmented areas is unknown, but so long as snaring remains uncontrolled, is moot.
USE AND TRADE
Owstons Civet is taken for meat and traditional medicine (including its bones, scent gland, and penis) in all of its range countries; there is not suspected to be any targeted hunting of the species, but much hunting in its range is non-selective (e.g. snares) to supply the general wildlife meat market (Sivilay et al. 2011, B. Long pers. comm. 2006, S.I. Roberton pers. comm. 2006).
CONSERVATION ACTIONS
Owstons Civet is listed as Endangered on the China Red List and as Vulnerable in the Viet Nam Red Book (MOSTE 2000). It is protected in Yunnan province, but not in Guangxi (GMA Small Carnivore Workshop 2006). In Viet Nam the species is listed in group IIB meaning exploitation is regulated but not prohibited (Decree 32/2006/ND-CP). In Lao PDR, the species is listed in group I (Prohibition category) of the hunting regulations (Prime Minister Decree 81, 2008; Wildlife hunting regulation).
An international breeding programme, coordinated from Viet Nam, has been established with populations in Europe and Viet Nam. However numbers are still too low for long-term viability (J. Meek pers. comm. 2014).
Owstons Civet has been recorded in many protected areas in Viet Nam and several in Lao PDR (Roberton 2007, Sivilay et al. 2011, Coudrat et al. 2014, Gray et al. 2014b) but in none of these is trade-driven snaring yet under effective control. They have, however, somewhat to greatly slowed the expansion of the road system, and thus maintained areas in which it is only marginally economically viable to harvest wildlife meat in bulk; and they have reduced the chance of landscape-level habitat transformation projects such as concession plantations. |
