Survival rates and causes of mortality of Amur tigers on and near the Sikhote-Alin Biosphere Zapovednik

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.