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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]

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]