Understanding the effects of human disturbance on endangered wildlife populations is critical to their conservation. We examined the effects of roads and human disturbance on the survivorship and foraging efficiency of Amur tigers ( Panthera tigris altaica ) on and near Sikhote-Alin State Biosphere Zapovednik, Primorye Krai (province), Russia. To evaluate the effects of roads, we estimated survivorship of radiocollared tigers and their cubs living in three types of areas: (1) areas with primary roads, (2) areas containing secondary roads, and (3) areas with minimal or no road access. We classified a tiger into one of these three treatments based on which types of roads bisected their 50% minimum convex polygon home ranges. Over a 9-year period (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000), adult female survival was greatest ( 2 ϭ 12.2, df ϭ 2, p ϭ 0.002) for radiocollared tigers in roadless areas. All adult female tigers in roadless areas survived their tenure in those locations ( n ϭ 2), whereas all died or disappeared prematurely from areas with primary roads ( n ϭ 6). Cub survival was lower in areas with primary and secondary roads than in roadless areas ( 2 ϭ 10.9, df ϭ 1, p Ͻ 0.009). We evaluated the effects of human disturbance at kill sites by examining 86 kills made by 15 tigers determining whether human disturbance had occurred at the kill site, and examining prey carcasses after tigers left, to estimate the percent meat eaten and whether the tiger abandoned the kill following human disturbance. Tigers undisturbed at kills consumed more meat ( Z ϭ 3.71, p ϭ 0.0002) from each kill than disturbed tigers did. Undisturbed tigers also spent more time at each kill site than disturbed tigers did ( Z ϭ 2.3; p ϭ 0.02). Abandonment of kills occurred in 63% of 24 instances when tigers were disturbed by people. Because roads decrease the survivorship and reproductive success of tigers, we recommend that in habitats managed for tigers, construction of new roads should be prohibited wherever possible and access to secondary roads (e.g., logging roads) should be reduced or prevented wherever possible. Protected areas seem to cease functioning as source populations where road access exists, and unprotected areas-the majority of Amur tiger rangecannot sustain stable populations with the increasing threat of human access to tiger habitat. Efectos de Caminos y Perturbación Humana sobre Tigres AmurResumen: Entender los efectos de la perturbación humana sobre poblaciones de vida silvestre en peligro es crítico para su conservación. Examinamos los efectos de caminos y perturbación humana sobre la supervivencia y eficiencia de forrajeo de tigres Amur ( Panthera tigris altaica ) en y cerca de Biosfera Estatal Zapovednik Sikhote-Alin, Primorye Krai ( provincia), Rusia. Para evaluar los efectos de los caminos, estimamos la supervivencia de tigres con radio-collares y sus crías en áreas de tres tipos: 1) áreas con caminos primarios, 2) áreas con caminos secundarios y 3) áreas con mínimo o sin acceso de caminos. Cla...

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 AE 0.10) was greater than that of adult males (0.63 AE 0.20) (z = 1.52, P= 0.13) and subadult males (0.41 AE 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.

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Canine distemper virus (CDV) has recently emerged as an extinction threat for the endangered Amur tiger (Panthera tigris altaica). CDV is vaccine-preventable, and control strategies could require vaccination of domestic dogs and/or wildlife populations. However, vaccination of endangered wildlife remains controversial, which has led to a focus on interventions in domestic dogs, often assumed to be the source of infection. Effective decision making requires an understanding of the true reservoir dynamics, which poses substantial challenges in remote areas with diverse host communities. We carried out serological, demographic, and phylogenetic studies of dog and wildlife populations in the Russian Far East to show that a number of wildlife species are more important than dogs, both in maintaining CDV and as sources of infection for tigers. Critically, therefore, because CDV circulates among multiple wildlife sources, dog vaccination alone would not be effective at protecting tigers. We show, however, that low-coverage vaccination of tigers themselves is feasible and would produce substantive reductions in extinction risks. Vaccination of endangered wildlife provides a valuable component of conservation strategies for endangered species.

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