Reconciling biome-wide conservation of an apex carnivore with land-use economics in the increasingly threatened Pantanal wetlands.

Conservation of carnivores involves finding solutions to minimize habitat loss and human-wildlife conflict. Understanding the nature of land-use economics can allow us to mitigate both threats. In the Pantanal, the two main economic activities are cattle ranching and ecotourism, each of which directly and indirectly affect the persistence of jaguars (Panthera onca). To understand how the geography of these economic activities is related to jaguar populations, we developed a jaguar distribution model (JDM), livestock density model, and ecotourism lodge density model for the Pantanal. Due to the recent wildfires within the Pantanal, we also assess the impact of burnt areas that are suitable for jaguars, cattle ranching, and tourism. Our JDM indicate that 64% of the Pantanal holds suitable habitat for jaguars. However, jaguar habitat suitability was positively correlated with ecotourism, but negatively correlated with areas most suitable for intensive cattle-ranching. This demonstrates a biome-wide scenario compatible with jaguar conservation. Of particular concern, recent wildfires overlap most suitable areas for jaguars. If wildfires become increasingly frequent, this would represent a serious threat to jaguars and many other wildlife populations. We emphasize the global importance of the Pantanal wetland ecoregion as a key stronghold for long-term jaguar conservation.

Pumas as ecosystem engineers: ungulate carcasses support beetle assemblages in the Greater Yellowstone Ecosystem.

Ecosystem engineers create physical changes in abiotic and biotic material, and through this process control the availability of resources for other species. Predators that abandon large portions of their prey may be ecosystem engineers that create habitat for carrion-dependent invertebrates that utilize carcasses during critical life-history periods. Between 04-May-2016 and 04-Oct-2016, we sampled beetle assemblages at 18 carcasses of prey killed by pumas and matching control sites in the southern Greater Yellowstone Ecosystem, USA, to measure the extent to which beetle families utilized these carcass "habitats". We used generalized linear-mixed models and linear-mixed effect models to examine changes in beetle abundance, species richness, and Simpson's Index of Diversity. We estimated kill rates and carrion production rates for individual pumas to better assess the impact of pumas on invertebrate communities. We collected 24,209 beetles representing 215 species. We identified eight beetle families that had significantly higher abundance at carcasses than control sites. Carcasses had a statistically large to very large effect (determined using Cohen's d) on beetle abundance, richness, and diversity for the initial 8 weeks of sampling. Our research revealed strong effects of an ecosystem engineer on beetle assemblages while highlighting the potential role of apex predators in creating and modifying physical habitats for carrion-dependent species. This suggests that there may be consequences for invertebrate communities where apex predators exist at reduced numbers or have been eradicated. The ecological role of invertebrates is often overlooked, yet they are essential taxa that provide critical ecological services upon which we depend.

Serosurvey of free-ranging Amur tigers in the Russian Far East.

Wild Amur tigers (Panthera tigris altaica, n=44) from the Russian Far East were tested for antibodies to feline leukemia virus, feline corona virus (FCoV), feline immunodeficiency virus, feline parvovirus (FPV), canine distemper virus (CDV), Toxoplasma gondii, and Bartonella henselae. Antibodies to FCoV, CDV, FPV, and T. gondii were detected in 43, 15, 68, and 42% of tigers, respectively. No differences were detected in antibody prevalence estimates between tigers captured as part of a research program and those captured to mitigate human-tiger conflicts. Domestic dogs (Canis familiaris) were tested as a potential source for CDV; 16% were vaccinated against CDV and 58% of unvaccinated dogs were antibody positive for CDV. A high percentage of tigers were exposed to potential pathogens that could affect the survival of this species. We recommend continued monitoring of wild tigers throughout Asia, development of standardized sampling and postmortem examination procedures, and additional research to better understand potential domestic and wild animal sources for these pathogens.

Sex-biased natal dispersal and inbreeding avoidance in American black bears as revealed by spatial genetic analyses.

We tested the hypothesis that sex-biased natal dispersal reduces close inbreeding in American black bears, a solitary species that exhibits nearly complete male dispersal and female philopatry. Using microsatellite DNA and spatial data from reproductively mature bears (>or= 4 years old), we examined the spatial genetic structure of two distinct populations in New Mexico from 1993 to 2000. As predicted, relatedness (r) and the frequency of close relationships (parent-offspring or full siblings) decreased with distance among female dyads, but little change was observed among male or opposite-sex dyads. Neighbouring females were more closely related than neighbouring males. The potential for inbreeding was low. Most opposite-sex pairs that lived sufficiently close to facilitate mating were unrelated, and few were close relatives. We found no evidence that bears actively avoided inbreeding in their selection of mates from this nearby pool, as mean r and relationship frequencies did not differ between potential and actual mating pairs (determined by parentage analysis). These basic patterns were apparent in both study areas despite a nearly two-fold difference in density. However, the sex bias in dispersal was less pronounced in the lower-density area, based on proportions of bears with male and female relatives residing nearby. This result suggests that male bears may respond to reduced competition by decreasing their rate or distance of dispersal. Evidence supports the hypothesis that inbreeding avoidance is achieved by means of male-biased dispersal but also indicates that competition (for mates or resources) modifies dispersal patterns.

Phylogeography and genetic ancestry of tigers (Panthera tigris).

Eight traditional subspecies of tiger (Panthera tigris),of which three recently became extinct, are commonly recognized on the basis of geographic isolation and morphological characteristics. To investigate the species' evolutionary history and to establish objective methods for subspecies recognition, voucher specimens of blood, skin, hair, and/or skin biopsies from 134 tigers with verified geographic origins or heritage across the whole distribution range were examined for three molecular markers: (1) 4.0 kb of mitochondrial DNA (mtDNA) sequence; (2) allele variation in the nuclear major histocompatibility complex class II DRB gene; and (3) composite nuclear microsatellite genotypes based on 30 loci. Relatively low genetic variation with mtDNA,DRB,and microsatellite loci was found, but significant population subdivision was nonetheless apparent among five living subspecies. In addition, a distinct partition of the Indochinese subspecies P. t. corbetti in to northern Indochinese and Malayan Peninsula populations was discovered. Population genetic structure would suggest recognition of six taxonomic units or subspecies: (1) Amur tiger P. t. altaica; (2) northern Indochinese tiger P. t. corbetti; (3) South China tiger P. t. amoyensis; (4) Malayan tiger P. t. jacksoni, named for the tiger conservationist Peter Jackson; (5) Sumatran tiger P. t. sumatrae; and (6) Bengal tiger P. t. tigris. The proposed South China tiger lineage is tentative due to limited sampling. The age of the most recent common ancestor for tiger mtDNA was estimated to be 72,000-108,000 y, relatively younger than some other Panthera species. A combination of population expansions, reduced gene flow, and genetic drift following the last genetic diminution, and the recent anthropogenic range contraction, have led to the distinct genetic partitions. These results provide an explicit basis for subspecies recognition and will lead to the improved management and conservation of these recently isolated but distinct geographic populations of tigers.

Effects of Roads and Human Disturbance on Amur Tigers.

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 (1991-2000), adult female survival was greatest (χ 2 = 12.2, df = 2, p = 0.002) for radiocollared tigers in roadless areas. All adult female tigers in roadless areas survived their tenure in those locations (n = 2), whereas all died or disappeared prematurely from areas with primary roads (n = 6). Cub survival was lower in areas with primary and secondary roads than in roadless areas (χ 2 = 10.9, df = 1, p < 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 = 3.71, p = 0.0002) from each kill than disturbed tigers did. Undisturbed tigers also spent more time at each kill site than disturbed tigers did ( Z = 2.3; p = 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 range-cannot sustain stable populations with the increasing threat of human access to tiger habitat.

RESUMEN: 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. Clasificamos un tigre en uno de estos tres tratamientos con base en cuales tipos de caminos dividen el 50 % mínimo del polígono convexo de sus rangos de hogar. En un período de 9 años (1991-2000), la supervivencia de hembras adultas fue mayor (χ 2 = 12.2, g.l. = 2, p = 0.002) en tigres con radio-collar en áreas sin caminos. Todas las hembras adultas en áreas sin caminos sobrevivieron su dominio en esas localidades (n = 2), mientras que todas murieron o desaparecieron prematuramente en las áreas con caminos primarios (n = 6). La supervivencia de crías fue menor en áreas con caminos primarios y secundarios que en áreas sin caminos (χ 2 = 10.9, g.l. = 1, p < 0.009). Evaluamos los efectos de la perturbación humana en sitios de depredación mediante el examen de 86 muertes causadas por 15 tigres, determinando si había ocurrido perturbación humana en el sitio, y mediante el examen de restos de las presas después de que se alejaron los tigres, para estimar el porcentaje de carne consumida y si el tigre abandonó su presa después de una perturbación humana. Los tigres no perturbados consumieron más carne ( Z = 3.71, p = 0.0002) de cada presa que los tigres perturbados. Tigres no perturbados pasaron más tiempo con su presa que tigres perturbados ( Z = 2.3, p = 0.02). El abandono de presas ocurrió en 63 % de 24 eventos cuando los tigres fueron perturbados por humanos. Debido a que los caminos reducen la supervivencia y el éxito reproductivo de los tigres, recomendamos que en los hábitats bajo manejo para tigres, se debe prohibir la construcción de caminos donde sea posible y se debe reducir o prevenir el acceso a caminos secundarios (e. g. caminos madereros) donde sea posible. Las áreas protegidas dejan de funcionar como poblaciones fuente donde existe acceso a caminos, y las áreas no protegidas ( la mayor parte del rango de tigre Amur) no pueden sostener poblaciones estables con la incremento en la amenaza del acceso humano al hábitat de los tigres.