Taxonomic Notes
We follow Luo et al. (2004), who confirmed the division of tigers into six extant subspecies on the basis of distinctive molecular markers:
Amur Tiger P. t. altaica: Russian Far East and northeastern China
Northern Indochinese Tiger P. t. corbetti: Indochina north of the Malayan peninsula
Malayan Tiger P. t. jacksoni: Peninsular Malaysia
Sumatran Tiger P. t. sumatrae: Sumatra
Bengal Tiger P. t. tigris: Indian sub-continent
South China Tiger P. t. amoyensis (although this subspecies has not been directly observed in the wild since the 1970s and is possibly extinct)
Three subspecies previously recognized on the basis of morphology are extinct:
Bali Tiger P. t. balica Schwarz, 1912: Bali
Javan Tiger P. t. sondaica (Temminck, 1844): Java
Caspian Tiger P. t. virgata (Illiger, 1815): dry river valleys of the Takla Makan, western slopes of the Tianshan mountains, Amudarya and Syrdarya river valleys, shores of the Caspian sea, Elburz mountains, eastern Turkey, Tigris and Euphrates river valleys.
Cracraft et al. (1998) considered the Sumatran Tiger to have a sufficiently distinct mitochondrial DNA to warrant species status. Mazak and Groves (2006) also considered the Sumatran Tiger a separate species on the basis of morphology, as well as the Javan Tiger.
On the basis of morphology, however, Kitchener (1999) considered that there is little evidence for discrete subspecies and morphological variation was best characterized as clinal.
Dinerstein et al. (1997) argued that a taxonomic approach to tiger conservation would seek to conserve only genetic variation, but that an ecological-based approach was needed to account for behavioral, demographic and ecological variation across tiger range. Sanderson et al. (2006) grouped tigers by biome (habitat type) and six bioregions that have some congruence with recognized subspecies: Indian sub-continent, Indochina, Peninsular Malaysia, Sumatra, Russian Far East, and China/Korea.
Justification
This species is Regionally Extinct in the Mediterranean.
Geographic Range Information
The tiger once ranged widely across Asia, from Turkey in the west to the eastern coast of Russia (Nowell and Jackson, 1996). Over the past 100 years tigers have disappeared from southwest and central Asia, from two Indonesian islands (Java and Bali) and from large areas of Southeast and Eastern Asia. Tigers have lost 93% of their historic range (Sanderson et al., 2006).
Tigers are currently found in twelve Asian range states: Bangladesh, Bhutan, Cambodia, China, India, Indonesia, Lao PDR, Malaysia, Myanmar, Nepal, Russia, Thailand and Viet Nam. They may still persist in North Korea, although there has been no recent confirmed evidence.
Sanderson et al. (2006) undertook an extensive collaborative exercise to map current tiger range. Priority areas for tigers were delineated and are called Tiger Conservation Landscapes, or TCLs. TCLs are defined as areas where there is sufficient habitat to conserve at least five tigers, and tigers have been confirmed to occur in the past decade. The range map shows the TCLs, and maps can be viewed in detail at the Save the Tiger Fund website: http://www.savethetigerfund.org/am/customsource/tiger/mapping/index.cfm
A total of 76 TCLs were delineated, with a total area of 1,184,911 km². TCLS vary in size, with the largest 269,983 km² in the Russian Far East and the smallest 278 km² in India. Most TCLs are small: 61 (80%) are less than 10,000 km² in area, and the median area for the entire set is just 2,904 km². Rabinowitz (1999) and Karanth and Nichols (2002) emphasize the importance of large core zones (>3,000 km²) with a healthy prey base for conservation of viable tiger populations.
However, tiger range is actually smaller than the total area of TCLS, because most TCLS contain area of non-tiger habitat where tigers cannot live (average 55% non-habitat, ranging from 20-70% of a TCL). The average amount of legally protected area within a TCL is shown below.
However, tigers do occur outside the TCLs. The exercise also identified 543 Fragments with Tigers - areas of habitat with confirmed tiger presence, but considered too small to support a long-term population. Also, 491 Tiger Survey Landscapes were highlighted - areas where tiger status is unknown, but where there is some reason to believe tigers might still be present, and which are large enough to support at least five tigers.
The Indian sub-continent (Bangladesh, India, Nepal, Bhutan, western Myanmar) is the bioregion with the most TCLS (40) and the highest number of TCLs assessed as being of global importance and of top priority for conservation (11). Total TCL area 227,569 km². Median TCL size 2,154 km². Average percent of TCL protected: 15.8%.
The Indochina bioregion (Myanmar, Cambodia, Lao PDR, Thailand and Viet Nam) has a smaller number of TCLs (20, with 6 of top priority) but the largest TCL total area of the four bioregions. Total TCL area 540,758 km². Median TCL size 5,288 km². Average percent of TCL protected: 29.2%.
The Southeast Asia bioregion supports 15 TCLs, with 3 of global priority. Total TCL area 145,285 km². Median TCL size 3,884 km². Average percent of TCL protected: 36.5%.
The Russian Far East bioregion (which includes small areas of northeastern China and North Korea) has just two TCLs, but includes the world's largest (269,983 km²). Total TCL area 271,297 km². Median TCL size 135,649 km². Average percent of TCL protected: 9.9%.
Tiger range has been shrinking not only historically, but also more recently. Comparison of current TCL area with a previous estimate a decade ago (Dinerstein et al. 1997) finds that tiger range has shrunk by 41% in the past ten years. This discrepancy is due in part to technical reasons including a better state of knowledge and improved tiger detection methodologies (Karanth et al., 2003, Sanderson et al., 2006). However, Dinerstein et al. (2007) consider tiger poaching and habitat loss to be important causes of this recent decline.
Although tiger range loss has been serious and steep, Sanderson et al. (2006) still consider 77% of current range to consist of "known and secured breeding populations of tigers in areas large enough for a substantive population." Roughly half of all TCLs are big enough to support an estimated 100 tigers or more, with the largest seven TCLs offering the potential to support 500 or more tigers. Even if tiger populations in these landscapes are below carrying capacity, these areas provide opportunities to increase tiger populations with appropriate conservation measures (Dinerstein et al. 2006).
Population Information
Scientific efforts to monitor tiger populations and estimate their size have increased in recent years (Gratwicke et al. 2006). A collation of national tiger estimates is given below. While some national populations can be estimated with confidence (notably Russia, India and Nepal), most are admittedly more speculative, ranging from application of site-specific density estimates over large areas to outright guesstimates. Putting all these national estimates together, the global tiger population is estimated to range from 3,402-5,140.
A previous compilation of national estimates to determine the global population estimated 5,000-7,000 tigers (Seidensticker et al. 1999). While most of these previous estimates were rough and lacked the scientific rigor that has gone into some recent estimates, so that a direct comparison is unreliable, a global population decline is suggested, as would be expected given the documented range reduction of 41% over the last decade (Sanderson et al. 2006).
In terms of conserving the wild tiger's genetic biodiversity, population biologists prefer to work with a number that approximates the actual breeding population, the number of animals which raise offspring to reproductive adulthood, or effective population size (Ne). The number of breeding tigers in one population was equivalent to just 40% of the actual adult population, based on long-term demographic studies in Nepal's Chitwan National Park (Smith and McDougal, 1991). Therefore, the tiger's effective population size could be in the range of 1,361-2,056 reproductively successful adults.
National tiger population estimates
Bangladesh: Tigers are now largely restricted to the Sundarbans mangrove forest. Estimating tiger density based on prey density, Khan (2004) estimated the population at 200. A higher estimate of 419 was obtained by the Bangladesh Ministry of Environment and Forests, which carried out a joint census with their Indian counterparts (MoEF 2004), using a methodology of identifying individual tigers from their tracks which has been criticized as yielding inaccurate results (Karanth et al. 2003). Based on the first data on home range collected from two radio-collared female tigers (11.5 and 13.9 km²), Barlow et al. (2007) roughly estimated there could be 95-286 female tigers in the Sundarbans. Estimate used for global population: 200-419
Bhutan: Dorji and Santiapillaai (1989) estimated Bhutan's tiger population at 151 (based on track counts) to 250 (extrapolating to unsurveyed areas). However, the density they used for their extrapolation (1 adult per 40 km²) was high for the more high-altitude parts of their range. In Jigme Singye Wangchuck National Park (where tigers have been recorded up to 4,500 m), Wang (2008) estimates, from camera trapping, a density of one tiger per 200 km². A similar density for the central Himalayan region was obtained from track surveys by McDougal and Tsering in the late 1990s, 1 tiger/185 km². Overall, their surveys estimated 67-81 adult tigers in Bhutan; this figure is used in the Govt of Bhutan's 2005 National Tiger Action Plan (Sangay and Wangchuk, 2005), although further research is necessary to clarify tiger abundance and distribution in the country (S. Wang pers. comm. 2008). Estimate used for global population: 67-81
Cambodia: Several NGOs working on tiger conservation held a meeting in 2004 to review data for the Tiger Conservation Landscape delineation exercise (Sanderson et al., 2006). Based on their work, using a range of methodologies including camera traps and field surveys by biologists and community wildlife rangers, Cambodia's tiger population was estimated at 11-50 tigers (Chheang et al. 2006).
China: The Govt of China, State Forest Administration, distributed a presentation at the 2007 International Tiger Symposium held April 2007 in Kathmandu, Nepal. The total tiger population in China was estimated at 37-50, broken down as follows. Amur tiger P.t. altaica (northeastern China) 18-22; Bengal tiger P.t. tigris (Motuo county, Tibet) 8-12; Indochinese tiger P.t. corbetti (southern Yunnan province) 11-16; South China tiger P.t. amoyensis (southern China) no definite evidence of continued persistence (Govt of China 2007, GTF 2007).
India: India's previous national tiger censuses were based on recognition of individual tiger tracks, and in 2001-2002 estimated the population at 3,642 tigers. This methodology was criticized by leading tiger scientists for being inaccurate and inefficient (Karanth et al. 2003). A new methodology has been developed as recommended by the 2005 tiger action plan (Govt of India 2005), using GIS mapping systems to extrapolate tiger densities derived from camera trap and sign-based indices of abundance. The Indian tiger population is now estimated at 1,411 (range 1,165-1,657 (Jhala et al. 2008). The Indian Sundarbans tiger population was not estimated. Because of the difference in methodology, it is not clear how much of the reduction from the 2001 estimate is due to actual loss of tigers as opposed to a more accurate census result.
Indonesia: The Sumatran tiger occurs in about 58,321 km² of forested habitat in 12 potentially isolated Tiger Conservation Landscapes totalling 88,351 km² (Sanderson et al. 2006), with about 37,000 km² protected in ten national parks (Govt of Indonesia 2007b). The tiger population was estimated at 400-500 in the first and second national tiger action plans (Govt of Indonesia 1994, 2007a), and at 342-509 in six major protected areas (estimates from Shepherd and Magnus 2004). However, incorporating more recent research (Linkie et al. 2006, Govt. of Indonesia 2007b), covering most of tiger estimated habitat (Sanderson et al. 2006), suggests the population could be 441-679 (see Red List assessment of Panthera tigris sumatrae for details). Understanding of Sumatran tiger status will improve when research in the three Tiger Conservation Landscapes in Riau province by Sunarto et al. (2007) is complete. Estimate used for global population: 441-679
Lao PDR: No population estimates are available, and Lao PDR is not included in the global population estimate. Tigers are known to occur in five (Duckworth et al. 1999) to seven areas (GTF 2007). One of the largest is the 3,446 km² (+ 854 km² proposed extension) Nam Et - Phou Louey National Protected Area. Based on camera trapping, tiger density there was estimated at 0.2-0.7 per 100 km², a relatively low density suggesting a population of only 7-23 tigers in the reserve (Johnson et al. 2006). Tigers and their large ungulate prey have have been depleted by hunting pressure across the country, and tiger numbers are likely to be low (Duckworth et al. 1999).
Malaysia: Based on typical prey biomass in tropical rainforests, energetic needs of tigers, estimated tiger densities from studies carried out in Taman Negara National Park, Malaysia, and others in tropical Asia, and available tiger habitats in Peninsular Malaysia, Kawanishi et al. (2003) estimated the national tiger population at 493-1,480 adult tigers. The lower bound coincides with the previous population estimate for the country (Topani 1990) and is the number selected as feasible by the country's national tiger action plan (DWNP 2008). However, based on density estimates derived from camera trapping in six sites in Malaysia during the late 1990s, Lynam et al. (2007) suggest a lower population, "up to several hundred." Estimate range used for global population: 300-493
Myanmar: The national tiger population was estimated at approximately 150, according to extensive surveys covering much of the country (Lynam 2003). Most tigers (approximately 100) are found in the large Hukaung Tiger reserve in the north of the country (Lynam et al. in prep.). Tigers have lost much of their historical range in Myanmar, and where they persist are at very low densities. The other important area for tigers is the forest complex found in northern and southern Taninthayi Division (approx. 50) (Lynam 2003).
Nepal: According to government representatives attending the 2007 International Tiger Symposium of the Global Tiger Forum, a 2006 exercise, based in part on camera trapping, estimated 350-370 tigers. The same number was obtained in 2005 and also in 1999-2000, and the population is considered stable (GTF 2007).
North Korea: There have been no surveys since 1998, when tiger tracks were reported along the border with China (Miquelle 1998).
Russia: In 2005 a comprehensive winter snow tracking census estimated 331-393 adult/sub-adult tigers. 977 fieldworkers covered 1537 transect routes totalling 26,031 km. Using a similar methodology, 330-371 adult tigers were estimated in 1996. The more recent number probably reflects more intensive survey effort (Miquelle et al. 2007).
Thailand: Tigers occur in 15 spatially disjunct forest complexes in Thailand (Smith et al. 1999), and were recorded in six out of seven forest complexes where camera trap surveys were carried out (Lynam et al. 2006). The best area for tigers is Huai Kha Khaeng National Park, with an estimated 113 tigers (Simcharoen et al. 2007). Extrapolating the density obtained from Huai Kha Khaeng (3.98 tigers per 100 km²) to the large 18,000 km² Western Forest complex, the largest habitat block for tigers in Thailand, Simcharoen et al. (2007) estimated it could hold 720 tigers, with the potential to harbor 2,000 if prey densities were to increase. However, this estimate should be treated as speculative pending further data from other parts of the Western Forest complex, where conditions are unlikely to be as good as in Huai Kha Khaeng. For example, the distribution map in Thailand's national tiger action plan portrays appoximately half of the Western Forest complex population as low density in comparison to the Huai Kha Khaeng population (Tunhikorn et al. 2004). In other Thai forest complexes, including Phu Khieo Wildlife Sanctuary (Lynam et al. 2001) and the Dong Phayayen-Khai Yai complex (Lynam et al. 2006), tigers were few, occurring at much lower densities than would have been predicted on the basis of habitat quality. Rabinowitz (1993), using presence/absence surveys and a modified arbitrary density estimate of 1 tiger per 100 km², estimated the Thai tiger population at no more than 250. Estimate range used for global population: 250-720.
Viet Nam: According to government representatives attending the 2007 International Tiger Symposium of the Global Tiger Forum, a 2004-2005 exercise estimated not more than 100 tigers in areas along the borders with Lao and Cambodia (GTF 2007).
Habitat and Ecology Information
Tigers are found only in the tropics of Asia. According to a recent comprehensive range mapping exercise (Sanderson et al., 2006), most tiger range is found in tropical and subtropical moist broadleaf forests (700,991 km², or 60% of tiger range). The second most common habitat type is temperate and broadleaf mixed forest (251,516 km², or 21% of tiger range), and the third is tropical and subtropical dry broadleaf forests (122,599 km², or 10% of tiger range). Other habitat types in which tigers are found include coniferous forest, mangrove forest, and tropical grass and shrubland. Photos of tigers up to 4,500 m have been obtained in Bhutan (Wang 2008).
Availability of a sufficient prey base of large ungulates is the tiger's major habitat requirement: "wild pigs and deer of various species are the two prey types that make up the bulk of the tiger's diet, and in general tigers require a good population of these species in order to survive and reproduce" (Sunquist and Sunquist, 2002). Based on studies, Karanth et al. (2004) estimate that tigers need to kill 50 large prey animals per year. Tigers are opportunistic predators, however, and their diet includes birds, fish, rodents, insects, amphibians, reptiles in addition to other mammals such as primates and porcupines. Tigers can also take ungulate prey much larger than themselves, including large bovids (water buffalo, gaur, banteng), elephants and rhinos (Nowell and Jackson 1996).
Tigers are generally solitary, with adults maintaining exclusive territories, or home ranges. Adult female home ranges seldom overlap, whereas male ranges typically overlap from 1-3 females, a typical felid pattern of social organization. Tiger home ranges are small where prey is abundant - eg, female home ranges in Chitwan averaged 20 km², while in the Russian Far East they are much larger at 450 km² (Sunquist and Sunquist, 2002). Similarly, reported tiger densities range from 11.65 adult tigers per 100 km² where prey is abundant (India's Nagarhole National Park) to as low as 0.13-0.45 per 100 km² where prey is more thinly distributed, as in Russia's Sikhote Alin Mountains (Nowell and Jackson, 1996).
Threats Information
Tiger range has contracted by 41% over the last decade (Sanderson et al., 2006). The sharpest decrease in area occurred in India, where landscapes with tigers were found to be much smaller and more fragmented than previously assessed in 1997.
While the reduction in range is due in some measure to improved knowledge of tiger distribution over the past decade, Dinerstein et al. (2007) consider habitat loss and poaching for trade to be primary causes of a significant decline in tiger range and numbers.
Asia is a densely populated and rapidly developing region, bringing huge pressures to bear on the large wild areas required for viable tiger populations. Conversion of forest land to agriculture and silviculture, commercial logging, and human settlement are the main drivers of tiger habitat loss. With their substantial dietary requirements, tigers require a healthy large ungulate prey base, but these species are also under heavy human subsistence hunting pressure and competition from domestic livestock. Karanth and Stith (1999) consider prey base depletion to be the leading threat to tigers in areas of otherwise suitable habitat.
In the early 1990s, it was feared that poaching of tigers for the use of their bones in traditional Asian medicine would drive the tiger to extinction (Nowell, 2000). Despite strong international action to eliminate it, illegal trade persists (Nowell, 2007). Tiger bone has long been considered to hold anti-inflammatory properties, with some support from Chinese medical research, but many consider the effect to be more psychological than pharmacological (Nowell and Xu, 2007). Although all countries have banned use and manufacture of tiger bone, illegal production persists in several Asian countries, especially in China, Malaysia, and Viet Nam (Nowell, 2007). In China there are several operations engaged in intensive breeding ("farming" of tigers), with the captive population reportedly reaching 5,000. They are pressuring the government to allow them to produce tiger products, and several are already engaged in illegal production of tiger bone wine. Market surveys indicate that medicinal use of tiger bone has decreased since China banned tiger bone in 1993. Tiger farming perpetuates and threatens to re-ignite consumer demand (Nowell and Xu, 2007).
There are other illegal markets for tiger products, especially skins, but also teeth and claws (particularly in Sumatra: Shepherd and Magnus, 2004; Ng and Nemora 2007), contributing to poaching pressure. But many tigers are also killed by people seeking to protect life and livestock. Conflict-killed tigers can also feed into the illegal trade. Many tiger products in trade are faked, a legal "grey area" in several countries which also perpetuates consumer demand (Nowell, 2000).
Tiger attacks on livestock and people can lead to intolerance of tigers by neighbouring communities and presents an ongoing challenge to managers to build local support for tiger conservation. In some areas there have been many human deaths - for example, 41 people were killed by tigers in the Sundarbans mangrove forest of Bangladesh during an 18-month period in 2001-2003 (Khan 2004).
Sanderson et al. (2006) surveyed 77 biologists about threats to tigers in the areas they work in, and compiled the results to indicate threat prevalence across tiger range. The top twelve threats are listed below, with their Vulnerability Scores: high scores indicate the threat is severe (e.g., it is reducing tiger populations), is urgent, and is widespread across tiger range.
Threat Vulnerability Score
Lack of law enforcement 1943
Hunting of tiger prey 1936
Low tiger population size 1909
Incidental hunting of tigers 1545
Lack of habitat connectivity 1510
Habitat degradation 1499
Export of tiger parts to other areas 1462
Habitat destruction 1386
Directed hunting of tigers 1325
Resource exploitation 1229
Local trade in tiger parts 1030
Lack of legal protection 586
Source: Sanderson et al. (2006: 14)
Use and Trade Information
Conservation Actions Information
Tigers have been the focus of substantial conservation effort and investment. Most range countries have developed or are developing national tiger conservation action plans (see Country Action Plan section of the Save the Tiger Fund website), and have called for IUCN to facilitate an international tiger conservation strategy (Nowell et al., 2007). A unique international conservation body, the Global Tiger Forum, brings together tiger range state governments with other governments and NGO members (GTF, 2007).
Tigers are included on CITES Appendix I, banning international trade, and all tiger range states as well as countries with consumer markets have banned domestic trade as well (although implementation has been uneven, and some legal loopholes remain (Nowell, 2007). At the 14th Conference of the Parties to CITES, stronger enforcement measures were called for, as well as an end to tiger farming (the production of tiger products from captive tigers) (Nowell et al., 2007).
National governments have invested huge resources in tiger conservation, including India, which has had a special Project Tiger program since the early 1970s. Increasingly, international inter-governmental organizations such as the World Bank are also supporting tiger conservation. Nongovernmental organizations have been very active. S. Christie (in Sanderson et al., 2006) analyzed tiger conservation funding by non-governmental organizations in the years 1998-2002. Over $23 million USD was invested, primarily in India, Russia, Indonesia, Malaysia and Nepal. The Save the Tiger Fund, funded in part by ExxonMobil, has invested 12.6 million USD in tiger conservation from 1995-2004 (Gratwicke et al., 2006).
To address the threat posed by habitat loss and fragmentation of the tiger population, the Wildlife Conservation Society and the Panthera Foundation announced plans on January 30 2008 to establish a 5,000 mile-long "genetic corridor" from Bhutan to Myanmar that would conserve a large contiguous tiger population. It would span eight countries and represent the largest block of tiger habitat left on earth. The proposed corridor includes extensive areas of Bhutan, northeast India, Myanmar, Thailand and Malaysia, along with potential connectivity to Lao PDR, Cambodia and Viet Nam. It was endorsed by the King of Bhutan, his Majesty Jigme Khesar Namgyel Wangchuck, who requested other heads of state to support similar efforts.
Sanderson et al. (2006) surveyed 77 biologists about the effectivess of conservation measures for tigers in the areas they work in (Tiger Conservation Landscapes), and compiled the results to indicate conservation effectiveness across tiger range. Scores for 22 conservation measures are given below; high scores indicate high effectiveness and widespread implemenation. Measures at the top of the list are widely implemented and considered effective. Measures in the middle require more effort, and measures at the bottom are perceived to be ineffective. Individual Tiger Conservation Landscapes which received the highest conservation effectivenss scores were in India, Bhutan, Nepal and Malaysia. Malaysia also had a number of Tiger Conservation Landscapes with the lowest scores, indicating lack of effective implementation.
Conservation Measure Effectiveness score
Education of local people 170
Education of school children 164
Training of protected area staff 159
Anti-poaching patrols 153
Monitoring of tigers in the field 152
Enforcement of protected area policies 149
Provisioning or monetary support to protected area staff 141
Enforcement of existing laws regarding tigers 135
Local publicity about tigers 133
Monitoring of prey populations 129
Anti-trafficking enforcement 104
Ecotourism ventures 104
Compensation programs 99
New laws/policies for tigers 93
Conflict management/mitigation 90
Monitoring of trade in tiger parts 80
New/upgraded protected area 78
Translocation of local people out of protected area 76
Habitat restoration 68
Habitat enhancement 58
Captive breeding facility 24
Reintroduction of tigers 8
