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Abstract: During the years 1992-2013, we studied the relationship between Amur tigers and brown and Asiatic black bears in the Sikhote-Alin Nature Reserve and surrounding areas in the southern part of the Russian Far East. To determine the importance of bears in the diet of tigers, 763 kills were located and identified, and 430 tiger scat samples were collected and analyzed. To detect kills and scat samples, we used radio telemetry and satellite tracking, as well as snow-tracking. Relying on evidence revealed by tracks, as well as radio telemetry, we determined whether bears exploited tiger kills as a food resource and how the two may have interacted at kill sites. Thirty-two Asiatic black bear and 12 brown bear den sites were measured to define properties that might assist in protection from the threat of a tiger attack. We identified 641 instances of marking on trees by both tigers and bears, an indication of the complexity of their relationship. Bears are an important part of the tigers' diet, representing 2.2% of all kills found. Bear remains were found in 8.4% of examined tiger scat. Bears exploited tiger kills after a tiger had left, by usurping a kill, or by "sharing" a kill at alternate times. The occurrence of den properties that provided some protection from tigers was dependent on the den type and location. Evidence of both tiger and bear marking was detected at 50.1% of marked trees. A review of the literature on the relationship of tigers and bears is provided. [ABSTRACT FROM AUTHOR]

Wild, solitary felids demonstrate a variety of spacing patterns, with diversity in spatial organization largely attributed to variations in abundance and distribution of important resources, particularly prey. We examined the relationship between territoriality of female Amur tigers Panthera tigris altaica and seasonal movements of a key prey species, Manchurian red deer Cervus canadensis xanthopygus, in the Russian Far East. We predicted that despite considerable seasonal fluctuations in productivity, red deer density does not change seasonally within tigress home ranges. We analyzed radio-telemetry data to identify directional movements of deer as an indicator of relative changes in seasonal red deer abundance and distribution, and we looked for seasonal shifts in home ranges of tigresses that could signify tracking of migratory prey. We failed to detect either seasonal shifts in tigress home ranges or significant differences in seasonal prey abundance. Most red deer were sedentary, while those that migrated demonstrated varying directionality of movements. Relatively low average snow depth likely reduced directional migratory tendencies in prey populations. Despite existing theory that might predict high overlap of Amur tiger home ranges, our results suggest that exclusive spacing patterns in this tiger subspecies are at least partly explained by the absence of major spatial and temporal changes in ungulate abundance and distribution. We submit that the assumption that home-range overlap should increase with increasing home-range size may require further evaluation in cases such as that of Amur tigers. [ABSTRACT FROM AUTHOR]

The Amur tiger ( Panthera tigris altaica) is a critically endangered felid that suffered a severe demographic contraction in the 1940s. In this study, we sampled 95 individuals collected throughout their native range to investigate questions relative to population genetic structure and demographic history. Additionally, we sampled targeted individuals from the North American ex situ population to assess the genetic representation found in captivity. Population genetic and Bayesian structure analyses clearly identified two populations separated by a development corridor in Russia. Despite their well-documented 20th century decline, we failed to find evidence of a recent population bottleneck, although genetic signatures of a historical contraction were detected. This disparity in signal may be due to several reasons, including historical paucity in population genetic variation associated with postglacial colonization and potential gene flow from a now extirpated Chinese population. Despite conflicting signatures of a bottleneck, our estimates of effective population size ( Ne = 27–35) and Ne /N ratio (0.07–0.054) were substantially lower than the only other values reported for a wild tiger population. Lastly, the extent and distribution of genetic variation in captive and wild populations were similar, yet gene variants persisted ex situ that were lost in situ. Overall, our results indicate the need to secure ecological connectivity between the two Russian populations to minimize loss of genetic diversity and overall susceptibility to stochastic events, and support a previous study suggesting that the captive population may be a reservoir of gene variants lost in situ. [ABSTRACT FROM AUTHOR]

Presents a study that examined the extend and phylogenetic pattern of DNA variation in wild-born and captive populations of the leopard Panthera pardus orientalis. Methodology; Results; Discussion.

Human-tiger conflict (HTC) fuels tiger population declines through retaliation killing by local people and government-sanctioned removal of problem individuals. This may have significant impacts on population persistence. In tigers and other large felids, broken canines are often assumed to be an infirmity that leads to HTC, but peer-reviewed literature does not support this. Thus, removal of animals with broken canines from the wild may result in unnecessary mortality. We examined data from wild Amur tigers to establish a baseline for degree of canine breakage in wild tigers not involved in conflict (referred to as 'research tigers'), to test for sex and age-related patterns in canine breakage and to estimate the impacts on survival and reproduction. We further compared canine breakage in research tigers to that in tigers captured or killed in HTC situations (HTC; 'conflict tigers'). We detected no difference ( P=0.76) in the percentage of tigers with broken canines between the two groups (24% in research tigers vs. 27% in conflict tigers) and no difference between sexes ( P=0.84), but the proportion of animals with broken canines increased with age class ( P<0.001). We detected no impact of canine breakage on survival or reproduction of research tigers and four research tigresses produced one to three litters each, despite one to three broken canines. Broken canines were considered a significant health issue in 2 of 17 cases, resulting in depredation in one case. Our data support the premise that broken canines do not usually represent a serious health issue and are usually not related to HTC. The assumption that broken canines lead to HTC appears invalid and may result in tigers being unnecessarily removed from the wild by managers. Similar results have been found for lions and the trend may be true for other large cats and carnivores as well. [ABSTRACT FROM AUTHOR]

For many purposes it is often desirable to estimate animal population densities over large areas. Where total counts are not possible and sightings are relatively rare, a range of methods exists to estimate densities from indirect sign. Such methods are frequently unreliable and usually require independent calibration or confirmation. We present an analytical method for estimating population density from track counts. The method, widely known in the Russian Federation but not in the English language scientific literature, requires counts of tracks of known age, together with estimates of animal daily travel distances. We use simulations to verify the theoretical basis of the approach and to indicate potential precision that may be achieved. We illustrate application of the approach using a large data set on ungulate track counts in the Russian Far East. We suggest that under most circumstances, nonparametric bootstrapping will be the most appropriate method for deriving estimates of confidence intervals about density estimates. As with other approaches to estimating density from indirect sign, the method that we discuss is vulnerable to violations of an array of underlying assumptions. However, it is easily applied and could represent an important method by which the relationship between indices of abundance and absolute density can be understood. [ABSTRACT FROM AUTHOR]

The serum prevalence of brown (Ursus arctos) and Asiatic black bears (Ursus thibethanus) to 14 different pathogens is analyzed; seropositive bears to ten different pathogens are found. The serum prevalence is at the maximum for Candida sp., pseudorabies virus and Dirofilaria sp. Species-specific differences in the serum prevalence to different pathogens are observed for Trichinella sp. and Toxoplasma gondii, but seropositive individuals are observed only among brown bears. These variations can be explained by differences in the feeding behavior of the brown and Asiatic black bears and the frequency of contacts with the Amur tiger and its kills. [ABSTRACT FROM AUTHOR]

The role of the Siberian musk deer in the diets of the Amur tiger, brown bear, and Asian black bear has been studied in the Sikhote-Alin State Biosphere Reserve in 1992 to 2016. Information has been collected from 763 tiger feeding sites, and the contents of tiger feces have been analyzed. Radiotelemetry has been used to evaluate tiger-musk deer relationships. The musk deer accounted for 0.26% of all animal species found to be eaten by the tiger. Musk deer remains in feces of the tiger, brown bear, and Asian black bear occurred with frequencies of 1.3, 0.2, and 0.3%, respectively. A case of musk deer avoiding the presence of brown bear is described. [ABSTRACT FROM AUTHOR]

Daily activity patterns of brown bears were monitored using radiotelemetry from 1993 to 2006, in the Sikhote-Alin Biosphere Reserve and adjacent areas. Outside of the denning period, bears were active for approximately 52% of the 24-hour period. Males were more active (64% of total time) than females (51%). Brown bears in the Sikhote-Alin are diurnal and crepuscular, but switch to a nocturnal pattern in areas of high anthropogenic influence. During the summer months, daily activity patterns were influenced by precipitation, cloud cover, and air temperature. [ABSTRACT FROM AUTHOR]

The future of wild tigers is dire, and the Global Tiger Initiative's ( GTI) goal of doubling tiger population size by the next year of the tiger in 2022 will be challenging. The GTI has identified 20 tiger conservation landscapes ( TCL) within which recovery actions will be needed to achieve these goals. The Amur tiger conservation landscape offers the best hope for tiger recovery in China where all other subspecies have most likely become extirpated. To prioritize recovery planning within this TCL, we used tiger occurrence data from adjacent areas of the Russian Far East to develop two empirical models of potential habitat that were then averaged with an expert-based habitat suitability model to identify potential tiger habitat in the Changbaishan ecosystem in Northeast China. We assessed the connectivity of tiger habitat patches using least-cost path analysis calibrated against known tiger movements in the Russian Far East to identify priority tiger conservation areas ( TCAs). Using a habitat-based population estimation approach, we predicted that a potential of 98 (83-112) adult tigers could occupy all TCAs in the Changbaishan ecosystem. By combining information about habitat quality, connectivity and potential population size, we identified the three best TCAs totaling over 25 000 km2 of potential habitat that could hold 79 (63-82) adult tigers. Strong recovery actions are needed to restore potential tiger habitat to promote recovery of Amur tigers in China, including restoring ungulate populations, increasing tiger survival through improved anti-poaching activities, land-use planning that reduces human access and agricultural lands in and adjacent to key TCAs, and maintaining connectivity both within and across international boundaries. Our approach will be useful in other TCLs to prioritize recovery actions to restore worldwide tiger populations. [ABSTRACT FROM AUTHOR]

We examined causes of mortality and survival rates for Amur tigers on and near the Sikhote-Alin Biosphere Zapovednik. Our objectives were to estimate and compare survival rates among sex and age classes, estimate cause-specific mortality, identify conservation issues related to tiger mortality and provide recommendations for reducing human-caused mortality. We used two separate datasets; one based on radio-tracking tigers from 1992 to 2005 and one based on reports of dead tigers from 1976 to 2000. We examined causes of mortality for both datasets and used a Cox proportional hazards models to estimate survival rates using data from 42 radio-collared tigers. Mortality was predominantly human-caused for both datasets (83% for the telemetry dataset and 78% for the other, n=24 and 53 mortalities, respectively), and 75% of collared animals were poached. All collared subadult tigers that dispersed were poached ( n=6). Annual survival of adult females (0.81±0.10) was greater than that of adult males (0.63±0.20) ( z=1.52, P=0.13) and subadult males (0.41±0.46) ( z=2.07, P=0.04). Survival rates were precariously low on our study area, which included the largest protected area within Amur tiger range. Efforts to reduce human-caused mortality should focus on poaching and reducing deaths from tiger–human conflicts. [ABSTRACT FROM AUTHOR]