In the beginning of 19th century, the range (areal) of Panthera tigris altaica included the forest part of the Korean Peninsula, the northern provinces of China, and the left bank of the Amur River in Russia and approached Transbaikalia and Yakutia. By the late 1930s, the number of tigers in Russia had decreased to 20–30 individuals. Protections against hunting (1947), the entrapment of tiger cubs (1965), and a lack of a market for tiger derivatives contributed to growth in tiger numbers. By the 1960s, the tiger population in Russia had increased to 100–110 individuals. According to a count in 1970, the population of tigers had reached 140–150 individuals. At this point in time, the range covered the forest territory of Primorsky Krai and southern Khabarovsky Krai. The last two total counts (1995–96 and 2004–05) revealed a further increase in the numbers to 450–500 animals and a range of 156,000 km2 . The latest recordings have confirmed the maximum numbers of tigers in the Sikhote-Alin and Lazovsky reserves and adjacent territories. However, the small areas of the reserves and their territorial separation preclude the maintenance of or increases in the population to or beyond 400–500 adult animals, which in genetic terms, would ensure the long-term conservation of the tiger. Further conservation of the region requires the assignment of two protective zones of 45,000–50,000 km2 with centres in the Sikhote-Alin and Lazovsky reserves. Within these protective zones, economic development involving any type of forest felling or ungulate hunting should be fully prohibited. The creation of protective zones is the only route to preserving the natural complex of the Sikhote-Alin, including the Amur tiger in Russia.
Amur tiger ; Panthera tigris altaica ; Far East ; Sikhote-Alin
At the beginning of the last century, the border of the area of the Amur tiger (Panthera tigris altaica ) covered the entire Korean peninsula. In China, the geographic habitat of the tiger occupied the basins of the Songhua River and Little and Great Khingan. Furthermore, the boundary followed to the east along the left bank of the Amur River to cross the Zeya River and then crossed the Amur River again (below the mouth of the Gorin River). The boundary of the geographic range extended to the mouth of the Samarga River and to the shores of the Sea of Japan.
In the north-eastern part of the habitat, the number of tigers was relatively stable. At that time, tigers were common on the left bank of the Amur River, on the ridge of the Shuah-Pokto and Bira and Bijan river valleys, in the Ussuri river basin and on the eastern slopes of the Sikhote-Alin (Abramov, 1970 ). According to Silantyev (2013) , in the Ussuri region in the 19th century, 120–150 tigers were hunted annually.
Although they were not permanently residents, tigers were often noted in Trans-Baikal. In 1820, one predator was shot in the Nerchinskii district, and another was killed in 1841 in the Onon river basin. Subsequent cases occurred again 1845 near Nerchinsk, close to the Agun River and three miles from the Argunskaya station (Cherkasov, 1990 ; Selsky, 1856 ).
In the beginning of the 20th century, tiger approaches occurred significantly less frequently in Trans-Baikal, which is likely attributable to a general decline in the tiger population in the Russian Far East. In the 1930s, this animal appeared in the upper reaches of the Zeya and Argu rivers.
According to the hunting specialist D. Chugunov, in 1931, the Fedorovs brothers hunted a tiger in the Amur Region (Chokchagur Mountain). In 1934, N.A. Khomenko saw a tiger in the Zeya area of the Amur region. In the same area, a frozen tiger was found a on the northern slope of the Stanovyi ridge. Occasionally tiger tracks were observed on Dzhagdy ridge and in the Argali river valley in the Amur region (Abramov, 1974 ). Below the Gorin River, along which Amur tigers had not always been present, some approaches have been observed to the east of the Nizhne-Tambovskoe village (Salmin, 1941 ).
In the beginning of the last century in the Amur–Ussuri region, the number of tigers decreased rapidly likely due to the decreases in ungulate, particularly wild boar, populations. Ungulate populations were particularly reduced after the snowy winter of 1914. That year, the boars disappeared almost completely. According to Kaplanov (1948) , the number of elk decreased by more than 1500 individuals. The tiger population might have declined for this reason.
By 1916, the tigers had disappeared from the eastern slopes of the Sikhote-Alin, and by the 30s of the 20th century, it became impossible to talk about a continuous tiger area. During this period, tigers were most common in the eastern part of the Girin province of China (PRC) to the east of the ridge of Laolin and the Little Khingan Mountains (Baikov, 1925 ). In the territories of Amur and Primorye, tigers remained in small groups that were isolated from each other along the Bureya, Bijan, Tyrma, Chur, Urmi, Khor, Bikin, Big Ussurka, and Ussuri rivers and in the south-western districts of Primorye. Currently, the majority of tiger sighting occur in the upper reaches of the Big Ussurka where 2–3 predators were hunted annually prior to the establishment of the Sikhote-Alin Reserve (1935).
By 1938–39 the tiger population had decreased even further in the Russian Far East. L. G. Kaplanov noted that the tiger population gradually decreased due to the capture and shooting of young adult tigers. At this time, tigers were most common in the Sikhote-Alin Reserve (10–12 individuals), and there were only 20–30 individuals in the Far East of Russia (Kaplanov, 1948 ).
By the 50s of the last century, tigers had disappeared from the southern part of the Korean Peninsula. The southern border of the tiger habitat was probably somewhere to the south of Pyongyang (Abramov, 1970 ). The area that was appropriate for tiger habitation along the Ussuri River and its main tributaries also decreased. In the remaining northern part of the area, the boundary shifted to the south. However, in the Russian Far East, local groups had been gradually merging, and a single area that covered the Anuy, Khor, Bikin, Big Ussurka, Malinovka, Zhuravlevka, Arsenievka basins and the rivers of the eastern Sikhote-Alin to the Malinovka River in the south began forming.
In the south-western areas of Primorye bordering China, tigers were observed along the Borisovka, Nezhinka, Ananievka, Amba, Barabashevka and Narva rivers. Single tigers appeared periodically in the Prikhankaysky border areas.
By the mid-1950s, the entrapment of young tigers had significantly increased. The main places of capture were the Dalnerechensky, Chuguevsky, Krasnoarmeysky and Kirovsky districts. The capturing of tigers was permitted without any restrictions. Essentially, all of the observed tiger cubs were being caught. Additionally, despite the official ban on tiger hunting, shootings by poachers continued to occur due to the existing demand for tiger skins and derivatives in China. This situation posed a threat to increases in the population and the existence of tigers. For example, from 1950 to 1960, in Primorye alone, at least 23 tigers were captured. The tiger population in the Russian Far East (i.e., the Primorsky and Khabarovsk Territories) did not exceed 58–60 individuals (Abramov, 1960 ).
In 1956, radical measures were taken to conserve the tiger. Specifically, a complete ban was placed on the capture of cubs. This measure was needed because the Primorye Zoologic Base could not provide the required conditions and professional personnel to maintain the animals. Consequently, another significant reduction in the number of trapped tigers occurred. Thus, in the winter of 1955–56, 15 tiger cubs were captured, and 13 died during maintenance and transportation to the central zoologic base (Moscow).
To streamline the economic use of tigers and their protection, the keeping of animal records was initiated in the winter of 1958–59. Abramov (1961) was the first to develop a methodology for tiger accounting and proposed the use of the width of the big subunguis (“heel”) of the predators forelimb as the primary parameter. As proposed by K. G. Abramov, the width of the “heel” remains the key indicator that is used for all counts of the Amur tiger. Additionally, the size of the “heel” is used for the specific identification of different individuals and assessments of their ages and genders (Miquelle et al ., 2006 ; Pikunov et al ., 2010 ; Pikunov et al ., 2014 ).
K. G. Abramov found that by the end of the winter of 1959 in Primorsky Krai, the tigers were remaining in the Pozharsky, Dalnerechensky, Krasnoarmeysky, Terneisky, Chuguyivsky, Olginsky, Partizansky, Shkotovsky, Yakovlevsky, Khasansky, Khankaisky, Dalnegorsky and Kavalerovsky districts of the Primorye Territory. At the same time, tigers were recorded in the Sikhote-Alin, Lazo and Ussuri Reserves. In 1959, it was found that there were 60–65 tigers in the entire territory of Primorsky Krai that included 12 adult males, 16 females (both with broods and single), 23 cubs, and 12–14 individuals of unknown gender and age (Abramov, 1962 ; Abramov, 1965 ).
According to a regional hunting inspection in the Khabarovsky Krai at the beginning of 1959, there were approximately 36 tigers. Several individuals lived in the Amurskaya oblast where they penetrated from the adjacent regions of the PRC. In Transbaikal, tigers were not observed in this period. Thus, at the beginning of 1959, the total number of individual tigers in the Russian Far East was estimated to be 100–110 individuals.
In the subsequent four years (1960–63), the tiger distribution exhibited some changes. In the northern parts of the area, the population density significantly decreased, particularly in the basins of the Bikin and Big Ussurka rivers. This decrease was likely due to the extensive development of the forests in the basins of these rivers and to significant decreases in the numbers of wild boar due to years of poor harvests of their main feed and snowy winters.
In the southern and south-eastern regions of Primorye (i.e., the basins of the Partizanskaya, Arsenievka, Ussuri and Ilistaya rivers) the number of tigers increased slightly during this period (Abramov, 1970 ). On the eastern slopes of the Sikhote-Alin Mountains, particularly in the vicinities of the bays of Vladimir, Olga, Valentin and Kievka, the tiger numbers clearly increased. Moreover, the appearance of the predators near settlements and even attacks on domestic animals had become more frequent. Thus, the regional hunt management of the Primorsky Krai Executive Committee, in consultation with the Central Hunt Management of the RSFSR, began to issue permits for the shooting of tigers.
In the winter of 1964, 12 adult tigers were observed crossing the state border with China in the Pogranichny and Khankaisky areas. Thus, a group of 15–17 individuals emerged (3–4 residents and the 12 newcomers). The Pogranichny and Khankaisky areas of Primorye are separated from the mountain range of the Sikhote-Alin by the vast treeless spaces of the Prikhankayskaya lowlands. Therefore, the tigers living here do not have contact with the animals that live in the mountain and forest areas of the Sikhote-Alin. It should also be noted that the lands that are appropriate for long-term tiger stays in the Khanka and border areas are too small, and probably for this reason, the migrant tigers either disappeared back to China or were illegally shot after some time.
The expansion of the northern and western borders of the tiger range that began in the mid-1950s probably continued until the early 1960s. At this time, the reverse reduction occurred place. Thus, in 1960–61 the tigers that had historically always dwelled in the Amur region disappeared from the fauna of the territory. In 1963–64, tigers ceased to visit the Jewish Autonomous Region. According to Kucherenko (1970) , at the beginning of 1968, the total number of tigers in the Primorsky Krai was 110–134 individuals, and 30% of this population was comprised of cubs.
Finally, in 1970, the number of tigers in the Primorsky Krai was estimated to be 124–131 individuals, and the estimate throughout Far East Russia was 144–151 individuals (Kazarinov, 1972 ; Yudakov and Nikolaev, 1972 ; Yudakov and Nikolaev, 1973 ).
By 1970, the tiger range in the Far East of Russia had decreased significantly compared to that in 1960. By this time, the predator had virtually disappeared from the left bank areas of the Amur River Region. The northern areas of the Sikhote-Alin (i.e., the Khungari and Anuy river basins) were also excluded from the geographic range. Along the eastern slopes of the Sikhote-Alin, the border shifted south to the Maksimovka river basin. Only by 1979 did single individual tigers (mostly males) appear occasionally on the left bank of the Anyuya and in the upper Copy and Botchi rivers (Kazarinov, 1979 ).
In 1979, tigers occupied the following two areas in the Far East of Russia:
This are is located in the Sikhote-Alin mountain system and extends from the western slopes to the south of the Khor river basin to the eastern slopes to the south of the Maksimovka River. In this part of the area, the border of the tiger distribution structure is determined by the habitat mosaic of the wild boar, and to a certain extent, the red deer and sika deer. Furthermore, the spread of the wild boar in Sikhote-Alin depends directly on the Korean pine and the Mongolian oak.
This area is located in the Khasansky and Nadezhdinsky districts and in the western part of the Ussurisky district of Primorsky Krai. This plot of 500,000 ha is separated from the first area by vast, open spaces and by a highway and railroad. Movements of tigers between these sections have not been registered. However, in the south-western parts of the cluster, the majority of the tiger habitat is beyond the state border and partially located in the adjacent areas of China.
The stable northern boundary of the Amur tiger area coincides with the northern boundary of the continuous range of the Ussuri boar. On the eastern slopes of the Sikhote-Alin, this border begins in the Maksimovka river basin. Visits by large males to the basins of Svetlaya, Yedinka and Samarga have been recorded in several years. Furthermore, approaches of the adult individuals might have occurred in the Samarga basin along the coast of the Sea of Japan and in the Khor river basin.
Regarding natural conditions, the most favourable habitat for the Amur tiger is the southern part of the Sikhote-Alin. However, it is precisely this region that has been affected by and is currently being exposed to growing anthropogenic pressure.
In the Middle Sikhote-Alin (north of Primorsky Krai), a continuous 80–100-km wide strip of Okhotsk-type vegetation ‘wedges in’ to cover the basins of the upper reaches of the Bikin and Big Ussurka rivers and the rivers of the eastern slope of Sikhote-Alin. The abundances of wild boar and red deer are much lower in this territory; therefore, there are no permanently dwelling tigers, although occasional visits of single adult males have been registered.
The results of tiger recordings in 1979 revealed an uneven distribution of animals in the territory of Primorsky Krai. The maximum population density of tigers (0.035–0.05 individuals per 1,000 ha) was detected in the Pozharsky, Olginskiy, Lazovsky and Yakovlevskiy districts of Primorye (overall area: 1,920,000 ha). Average population densities (0.017–0.019 individuals per 1,000 ha) were identified in the Krasnoarmeysky and Kirovsky districts of Primorye. The minimum population densities (less than 0.015 individuals per 1,000 ha) were registered in the following districts: Kavalerovsky, Lesozavodsky, Chuguevsky, Spassky, Chernigovsky, Shkotovsky, and Ussurisky.
The total number of tigers in 1979 in Primorsky Krai was 172–195 individuals, and the habitat area comprised 97,150 km2 . Between 1969 and 1979 in the Khankaisky and Pogranichny districts of Primorye, there were no reports of the presence of tigers (Pikunov et al., 1983 ).
In the 1970s, increases in the population and density of tigers occurred in the northern parts of the range and can be explained by improved trophic conditions and improved habitat preservation against various human influences. During the same time period, tigers died due to various causes: 78 were shot (both with permits and uncovered poaching); 37 cubs were captured alive for zoos; and the natural causes accounted for the deaths of approximately 15 individuals. In total, more than 130 tigers died.
Litter numbers and the safety of cubs are directly dependent on the extent of human influence. As the population grows and the taiga is exploited, the most effective measure for saving tigers will be to increase the prey population density. The environmental conditions of the region make it possible to significantly increase the densities of the wild boar, red deer, sika deer and roe deer populations. Such increases will not require expensive biotechnological activities. Funds are needed for more effective protection of ungulates, i.e., strict compliance with the rules of shooting licenses, restrictions, and even a complete local ban on the hunting of ungulates. Otherwise, it will be impossible not only to foster an increase in but also to maintain the existing tiger population.
A comparison of the boundaries of the ranges and distributions of tigers in 1970 (Yudakov and Nikolaev, 1973 ) with those in 1978–79 (Pikunov et al., 1983 ) revealed expansions in the area and increases in numbers occurred mainly in the northern regions of Primorye. By 1984–85, increases in the numbers of tigers had occurred in essentially all parts of the range. These increases were facilitated by the preservation of habitats and the consequently more favourable environmental conditions (primarily a sufficiently large and stable ungulate population).
The results of recordings from 1984–85 revealed a further increase in the area of the tiger habitat in Primorsky Krai to 108,500 km2 (Pikunov, 1990 ). Later, in the winter of 1995–96, the increase of the range in the Primorsky Territory continued to 123,000 km2 , the range throughout the Far East of Russia expanded to 156,000 km2 , and the number individuals increased to 415–476 (Matyushkin et al ., 1996 ; Matyushkin et al ., 1999 ; Miquelle et al ., 2005 ).
The results of monitoring in 1995–96 and 2005 confirmed that these predators continue to exist at the maximum population density in the protected areas. This pattern was observed in almost all of the previous counts, but it was less pronounced. Simultaneously, it became more apparent that reserves in small areas (i.e., Sikhote-Alin, 401,600 ha; Lazovsky, 150,000 ha; and Ussurisky, 40,400 ha) and will not be able to solve the problem of tiger conservation the Russian Far East due to the disunity of those areas. The solution to this problem requires a system of large reserves, including protected areas, that are connected with one another.
Unfortunately, given the current conditions, it does not seem possible to maintain a single, integrated tiger population numbering 450–500 mature individuals. There are no remaining appropriate continuous habitats in the Sikhote-Alin that could maintain such a population. Therefore, the only way to ensure the long-term preservation of the integrity of the Ussuri taiga natural complex (of which the Siberian tiger is an essential component) is to create two new protected areas in the south of the Far East. The need to provide “protected zones” and connect them with ecological corridors was proposed the experts authors of the three latest Amur tiger counts (1984–85, 1995–96, and 2004–05).
First, the northern buffer zone should include the entire area of the remaining middle course of the basin of Bikin (Pozharsky district), the eastern part of the Krasnoarmejskiy district (the basins of the Large Ussurka right tributaries), the north-eastern part of the Dalnerechensky district, the Sikhote-Alin Reserve and the entire southern part of the Terneisky district to the Maksimovka river basin inclusively. The area of this zone is approximately 33,000–35,000 km2 .
Second, the southern protected zone should encompass the Lazovsky and Olginsky districts, the territory of the Lazovsky Reserve and the adjacent parts of the Partyzansky and Kavalerovsky districts. The area of this zone would comprise 13,000–15,000 km2 .
The rest of the Primorsky Territory is unlikely to be useful for the preservation of tigers in the future due to impending industrial development.
In the territories of the proposed protected zones, it will be necessary to completely restrict all types of logging and animal hunting. Moreover, it is also important to increase the prestige and level of game management in the adjacent areas with the goal of increasing the densities of the ungulate populations (Matyushkin et al., 1999 ).
Examinations of the results of the last two tiger counts (1995–96 and 2004–05), particularly the one from 1984–85, clearly demonstrate that expansions of the range to the north and deeper into the Sikhote-Alin have occurred. Tigers have gradually settled in the Samarga river basin and part of the upper Bikin River in which the living conditions for these predators are far from optimal. Simultaneously, reductions in tiger numbers have occurred in the central and southern regions of the Sikhote-Alin as these regions have become more accessible to humans.
The increases in range and population growth apparently continued until the 1990s. Efforts to preserve tiger habitats (e.g., a ban on the logging of Korean pine, restrictions on the hunting of ungulates, and the creation of new reserves) have succeeded to some extent. Population losses due to the increased poaching motivated by the strong demand for and high prices of tiger derivatives have apparently matched the reproductive capacity of the population (Table 1 ) as evidenced by the results of the monitoring studies conducted from 1998 to 2012. However, in some areas of Primorye and Khabarovsky krai, imbalances between the numbers of tigers and their foraging resources have become evident.
|District of Primorsky Krai||Degree of anthropogenic pressure||Portion (%) of young animals in the group|
The regular occurrence of the maximum numbers of tigers in the reserves and other protected areas (PAs) is particularly clearly demonstrated by the results of recent surveys (1984–85, 1995–96 and 2004–05). The increased attraction of tigers to the reserve areas has undoubtedly been caused by the degradation and deterioration of the habitats outside protected areas. These areas have suffered decreases small ungulate populations, poaching and the deterioration of habitat due to intensive logging, the development of forest road networks and a general increase anxiety-inducing factors. The transformation of habitats has led to a reduction in the suitable living space for tigers and ungulates and will progress in the future. In this regard, nature reserves and other protected areas that are small and not connected will not solve the problem of tiger preservation.
The present area of the tiger in the Russian Far East is 156,000–160,000 km2 (Matyushkin et al ., 1996 ; Matyushkin et al ., 1999 ; Miquelle et al ., 2006 ; Pikunov, 1990 ). Increases in the Ussurisky and Lazovsky reserve areas with protection zones and connecting ecological corridors will guarantee the preservation of much of the modern population of the Amur tiger. The proposed additional protected areas, incombination with the existing protected areas, represent the minimum habitat that is absolutely necessary to guarantee the long-term preservation of the landscape and its constituent elements in the face of radical restructuring of the natural environment of the area of the Amur tiger in the future.