Willow on Yellowstone's northern range: evidence for a trophic cascade?

Reintroduction of wolves (Canis lupus) to Yellowstone National Park in 1995-1996 has been argued to promote a trophic cascade by altering elk (Cervus elaphus) density, habitat-selection patterns, and behavior that, in turn, could lead to changes within the plant communities used by elk. We sampled two species of willow (Salix boothii and S. geyeriana) on the northern winter range to determine whether (1) there was quantitative evidence of increased willow growth following wolf reintroduction, (2) browsing by elk affected willow growth, and (3) any increase in growth observed was greater than that expected by climatic and hydrological factors alone, thereby indicating a trophic cascade caused by wolves. Using stem sectioning techniques to quantify historical growth patterns we found an approximately twofold increase in stem growth-ring area following wolf reintroduction for both species of willow. This increase could not be explained by climate and hydrological factors alone; the presence of wolves on the landscape was a significant predictor of stem growth above and beyond these abiotic factors. Growth-ring area was positively correlated with the previous year's ring area and negatively correlated with the percentage of twigs browsed from the stem during the winter preceding growth, indicating that elk browse impeded stem growth. Our results are consistent with the hypothesis of a behaviorally mediated trophic cascade on Yellowstone's northern winter range following wolf reintroduction. We suggest that the community-altering effects of wolf restoration are an endorsement of ecological-process management in Yellowstone National Park.     

Spatial and temporal changes in group dynamics and range use enable anti-predator responses in African buffalo

The reintroduction of large predators provides a framework to investigate responses by prey species to predators. Considerable research has been directed at the impact that reintroduced wolves (Canis lupus) have on cervids, and to a lesser degree, bovids, in northern temperate regions. Generally, these impacts alter feeding, activity, and ranging behavior, or combinations of these. However, there are few studies on the response of African bovids to reintroduced predators, and thus, there is limited data to compare responses by tropical and temperate ungulates to predator reintroductions. Using the reintroduction of lion (Panthera leo) into the Addo Elephant National Park (AENP) Main Camp Section, South Africa, we show that Cape buffalo (Syncerus caffer) responses differ from northern temperate ungulates. Following lion reintroduction, buffalo herds amalgamated into larger, more defendable units; this corresponded with an increase in the survival of juvenile buffalo. Current habitat preference of buffalo breeding herds is for open habitats, especially during the night and morning, when lion are active. The increase in group size and habitat preference countered initial high levels of predation on juvenile buffalo, resulting in a return in the proportion of juveniles in breeding herds to pre-lion levels. Our results show that buffalo responses to reintroduced large predators in southern Africa differ to those of northern temperate bovids or cervids in the face of wolf predation. We predict that the nature of the prey response to predator reintroduction is likely to reflect the trade-off between the predator selection and hunting strategy of predators against the life history and foraging strategies of each prey species.     

Longitudinal Analysis of Attitudes Toward Wolves

Understanding individual attitudes and how these predict overt opposition to predator conservation or direct, covert action against predators will help to recover and maintain them. Studies of attitudes toward wild animals rely primarily on samples of individuals at a single time point. We examined longitudinal change in individuals’ attitudes toward gray wolves (Canis lupus). In the contiguous United States, amidst persistent controversy and opposition, abundances of gray wolves are at their highest in 60 years. We used mailed surveys to sample 1892 residents of Wisconsin in 2001 or 2004 and then resampled 656 of these individuals who resided in wolf range in 2009. Our study spanned a period of policy shifts and increasing wolf abundance. Over time, the 656 respondents increased agreement with statements reflecting fear of wolves, the belief that wolves compete with hunters for deer (Odocoileus virginianus), and inclination to poach a wolf. Endorsement of lethal control of wolves by the state and public hunting of wolves also increased. Neither the time span over which respondents reported exposure to wolves locally nor self‐reported losses of domestic animals to wolves correlated with changes in attitude. We predict future increases in legal and illegal killing of wolves that may reduce their abundance in Wisconsin unless interventions are implemented to improve attitudes and behavior toward wolves. To assess whether interventions change attitudes, longitudinal studies like ours are needed. Análisis Longitudinal de las Actitudes Hacia Lobos     

Genetic Variation of Naturally Colonizing Wolves in the Central Rocky Mountains

Recovery of gray wolf ( Canis lupus ) populations in North America depends on minimizing human-caused mortality and enhancing migration from stable source populations to suitable habitat unoccupied by wolves. We used a combination of field observation and DNA microsatellite genotyping to examine natural wolf colonization of Glacier National Park, Montana, and surrounding lands. We found high genetic variation in the colonizing population, showing that these packs were founded by multiple, unrelated wolves from Canada. High dispersal rates, long dispersal distances, and lack of a founding population bottleneck indicate that wolves in the United States and Canada should be viewed and managed as a single population. Restoration in the United States by artificial transplants from Alberta to Yellowstone National Park and central Idaho began in 1995. The transplanted wolves will likely aid demographic recovery, but permanently retaining the high genetic variation of wolves in the United States will require assuring gene flow throughout the central Rocky Mountains.     

Are wolves saving Yellowstone's aspen? A landscape-level test of a behaviorally mediated trophic cascade

Behaviorally mediated trophic cascades (BMTCs) occur when the fear of predation among herbivores enhances plant productivity. Based primarily on systems involving small-bodied predators, BMTCs have been proposed as both strong and ubiquitous in natural ecosystems. Recently, however, synthetic work has suggested that the existence of BMTCs may be mediated by predator hunting mode, whereby passive (sit-and-wait) predators have much stronger effects than active (coursing) predators. One BMTC that has been proposed for a wide-ranging active predator system involves the reintroduction of wolves (Canis lupus) to Yellowstone National Park, USA, which is thought to be leading to a recovery of trembling aspen (Populus tremuloides) by causing elk (Cervus elaphus) to avoid foraging in risky areas. Although this BMTC has been generally accepted and highly popularized, it has never been adequately tested. We assessed whether wolves influence aspen by obtaining detailed demographic data on aspen Stands using tree rings and by monitoring browsing levels in experimental elk exclosures arrayed across a gradient of predation risk for three years. Our study demonstrates that the historical failure of aspen to regenerate varied widely among stands (last recruitment year ranged from 1892 to 1956), and our data do not indicate an abrupt cessation of recruitment. This pattern of recruitment failure appears more consistent with a gradual increase in elk numbers rather than a rapid behavioral shift in elk foraging following wolf extirpation. In addition, our estimates of relative survivorship of young browsable aspen indicate that aspen are not currently recovering in Yellowstone, even in the presence of a large wolf population. Finally, in an experimental test of the BMTC hypothesis we found that the impacts of elk browsing on aspen demography are not diminished in sites where elk are at higher risk of predation by wolves. These findings suggest the need to further evaluate how trophic cascades are mediated by predator-prey life history and ecological context.     

A meta‐analysis of studies on attitudes toward bears and wolves across Europe 1976–2012

The ranges of wolves (Canis lupus) and bears (Ursus arctos) across Europe have expanded recently, and it is important to assess public attitudes toward this expansion because responses toward these species vary widely. General attitudes toward an object are good predictors of broad behavioral patterns; thus, attitudes toward wolves and bears can be used as indicators to assess the social foundation for future conservation efforts. However, most attitude surveys toward bears and wolves are limited in scope, both temporally and spatially, and provide only a snapshot of attitudes. To extend the results of individual surveys over a much larger temporal and geographical range so as to identify transnational patterns and changes in attitudes toward bears and wolves over time, we conducted a meta‐analysis. Our analysis included 105 quantitative surveys conducted in 24 countries from 1976 to 2012. Across Europe, people's attitudes were more positive toward bears than wolves. Attitudes toward bears became more positive over time, but attitudes toward wolves seemed to become less favorable the longer people coexisted with them. Younger and more educated people had more positive attitudes toward wolves and bears than people who had experienced damage from these species, and farmers and hunters had less positive attitudes toward wolves than the general public. For bears attitudes among social groups did not differ. To inform conservation of large carnivores, we recommend that standardized longitudinal surveys be established to monitor changes in attitudes over time relative to carnivore population development. Our results emphasize the need for interdisciplinary research in this field and more advanced explanatory models capable of capturing individual and societal responses to changes in large carnivore policy and management.     

Recolonizing wolves and mesopredator suppression of coyotes: impacts on pronghorn population dynamics.

Food web theory predicts that the loss of large carnivores may contribute to elevated predation rates and, hence, declining prey populations, through the process of mesopredator release. However, opportunities to test predictions of the mesopredator release hypothesis are rare, and the extent to which changes in predation rates influence prey population dynamics may not be clear due to a lack of demographic information on the prey population of interest. We utilized spatial and seasonal heterogeneity in wolf distribution and abundance to evaluate whether mesopredator release of coyotes (Canis latrans), resulting from the extirpation of wolves (Canis lupus) throughout much of the United States, contributes to high rates of neonatal mortality in ungulates. To test this hypothesis, we contrasted causes of mortality and survival rates of pronghorn (Antilocapra americana) neonates captured at wolf-free and wolf-abundant sites in western Wyoming, USA, between 2002 and 2004. We then used these data to parameterize stochastic population models to heuristically assess the impact of wolves on pronghorn population dynamics due to changes in neonatal survival. Coyote predation was the primary cause of mortality at all sites, but mortality due to coyotes was 34% lower in areas utilized by wolves (P < 0.001). Based on simulation modeling, the realized population growth rate was 0.92 based on fawn survival in the absence of wolves, and 1.06 at sites utilized by wolves. Thus, wolf restoration is predicted to shift the trajectory of the pronghorn population from a declining to an increasing trend. Our results suggest that reintroductions of large carnivores may influence biodiversity through effects on prey populations mediated by mesopredator suppression. In addition, our approach, which combines empirical data on the population of interest with information from other data sources, demonstrates the utility of using simulation modeling to more fully evaluate ecological theories by moving beyond estimating changes in vital rates to analyses of population-level impacts.     

Prey risk allocation in a grazing ecosystem.

Understanding the behaviorally mediated indirect effects of predators in ecosystems requires knowledge of predator-prey behavioral interactions. In predator-ungulate-plant systems, empirical research quantifying how predators affect ungulate group sizes and distribution, in the context of other influential variables, is particularly needed. The risk allocation hypothesis proposes that prey behavioral responses to predation risk depend on background frequencies of exposure to risk, and it can be used to make predictions about predator-ungulate-plant interactions. We determined non-predation variables that affect elk (Cervus elaphus) group sizes and distribution on a winter range in the Greater Yellowstone Ecosystem (GYE) using logistic and log-linear regression on surveys of 513 1-km2 areas conducted over two years. Employing model selection techniques, we evaluated risk allocation and other a priori hypotheses of elk group size and distributional responses to wolf (Canis lupus) predation risk while accounting for influential non-wolf-predation variables. We found little evidence that wolves affect elk group sizes, which were strongly influenced by habitat type and hunting by humans. Following predictions from the risk allocation hypothesis, wolves likely created a more dynamic elk distribution in areas that they frequently hunted, as elk tended to move following wolf encounters in those areas. This response should dilute elk foraging pressure on plant communities in areas where they are frequently hunted by wolves. We predict that this should decrease the spatial heterogeneity of elk impacts on grasslands in areas that wolves frequently hunt. We also predict that this should decrease browsing pressure on heavily browsed woody plant stands in certain areas, which is supported by recent research in the GYE.     

Consensus on Criteria for Potential Areas for Wolf Reintroduction in Mexico

Abstract: Given the conflict with human interests that in many cases results in the extirpation of large carnivores, acceptance of their reintroduction is a considerable challenge. By the 1980s Mexican wolves (Canis lupus) were extinct in the wild. In 1998 a population was reintroduced in the Blue Range Mountains of New Mexico (U.S.A.). Efforts to reintroduce the species in Mexico have been ongoing since the late 1980s. Four teams working independently identified 6 areas in northern Mexico in the historic range of Mexican wolves, where reintroductions could potentially be successful. Each team used different methods and criteria to identify the areas, which makes it difficult to prioritize among these areas. Therefore, members of the different teams worked together to devise criteria for use in identifying priority areas. They identified areas with high, intermediate, and low potential levels of conflict between wolves and humans. Areas with low potential conflict had larger buffers (i.e., distance from human settlement to areas suitable for wolves) around human settlements than high‐ and intermediate‐conflict areas and thus were thought most appropriate for the first reintroduction. High‐conflict areas contained habitat associated with wolf presence, but were closer to human activity. The first reintroduction of Mexican wolves to Mexico occurred in October 2011 in one of the identified low‐conflict areas. The identification of suitable areas for reintroduction represents a crucial step in the process toward the restoration of large carnivores. Choice of the first reintroduction area can determine whether the reintroduction is successful or fails. A failure may preclude future reintroduction efforts in a region or country.     

The Role of Translocation in Recovery of Woodland Caribou Populations

Abstract: Maintenance of viable populations of many endangered species will require conservation action in perpetuity. Efforts to conserve these species are more likely to be successful if their reliance on conservation actions is assessed at the population level. Woodland caribou (Rangifer tarandus caribou) were extirpated recently from Banff National Park, Canada, and translocations of caribou to Banff and neighboring Jasper National Park are being considered. We used population viability analysis to assess the relative need for and benefits from translocation of individuals among caribou populations. We measured stochastic growth rates and the probability of quasi extinction of four populations of woodland caribou with and without translocation. We used two vital rates in our analysis: mean adult female survival and mean number of calves per breeding‐age female as estimates of mean fecundity. We isolated process variance for each vital rate. Our results suggested the Tonquin caribou population in Jasper is likely to remain viable without translocation, but that translocation is probably insufficient to prevent eventual extirpation of the two other populations in Jasper. Simulated reintroductions of caribou into Banff resulted in a 53–98% probability of >8 females remaining after 20 years, which suggests translocation may be an effective recovery tool for some caribou populations.     

Indirect effects and traditional trophic cascades: a test involving wolves, coyotes, and pronghorn

The traditional trophic cascades model is based on consumer resource interactions at each link in a food chain. However, trophic-level interactions, such as mesocarnivore release resulting from intraguild predation, may also be important mediators of cascades. From September 2001 to August 2004, we used spatial and seasonal heterogeneity in wolf distribution and abundance in the southern Greater Yellowstone Ecosystem to evaluate whether mesopredator release of coyotes (Canis latrans), resulting from the extirpation of wolves (Canis lupus), accounts for high rates of coyote predation on pronghorn (Antilocapra americana) fawns observed in some areas. Results of this ecological perturbation in wolf densities, coyote densities, and pronghorn neonatal survival at wolf-free and wolf-abundant sites support the existence of a species-level trophic cascade. That wolves precipitated a trophic cascade was evidenced by fawn survival rates that were four-fold higher at sites used by wolves. A negative correlation between coyote and wolf densities supports the hypothesis that interspecific interactions between the two species facilitated the difference in fawn survival. Whereas densities of resident coyotes were similar between wolf-free and wolf-abundant sites, the abundance of transient coyotes was significantly lower in areas used by wolves. Thus, differential effects of wolves on solitary coyotes may be an important mechanism by which wolves limit coyote densities. Our results support the hypothesis that mesopredator release of coyotes contributes to high rates of coyote predation on pronghorn fawns, and demonstrate the importance of alternative food web pathways in structuring the dynamics of terrestrial systems.     

Assessment of prey vulnerability through analysis of wolf movements and kill sites.

Within predator-prey systems behavior can heavily influence spatial dynamics, and accordingly, the theoretical study of how spatial dynamics relate to stability within these systems has a rich history. However, our understanding of these behaviors in large mammalian systems is poorly developed. To address the relationship between predator selection patterns, prey density, and prey vulnerability, we quantified selection patterns for two fine-scale behaviors of a recovering wolf (Canis lupus) population in Yellowstone National Park, Wyoming, USA. Wolf spatial data were collected between November and May from 1998-1999 until 2001-2002. Over four winters, 244 aerial locations, 522 ground-based telemetry locations, 1287 km of movement data from snow tracking, and the locations of 279 wolf kill sites were recorded. There was evidence that elk (Cervus elaphus) and bison (Bison bison) densities had a weak effect on the sites where wolves traveled and made kills. Wolf movements showed a strong selection for geothermal areas, meadows, and areas near various types of habitat edges. Proximity to edge and habitat class also had a strong influence on the locations where elk were most vulnerable to predation. There was little evidence that wolf kill sites differed from the places where wolves traveled, indicating that elk vulnerability influenced where wolves selected to travel. Our results indicate that elk are more vulnerable to wolves under certain conditions and that wolves are capable of selecting for these conditions. As such, vulnerability plays a central role in predator-prey behavioral games and can potentially impact the systems to which they relate.     

Multiscale Factors Affecting Human Attitudes toward Snow Leopards and Wolves

The threat posed by large carnivores to livestock and humans makes peaceful coexistence between them difficult. Effective implementation of conservation laws and policies depends on the attitudes of local residents toward the target species. There are many known correlates of human attitudes toward carnivores, but they have only been assessed at the scale of the individual. Because human societies are organized hierarchically, attitudes are presumably influenced by different factors at different scales of social organization, but this scale dependence has not been examined. We used structured interview surveys to quantitatively assess the attitudes of a Buddhist pastoral community toward snow leopards (Panthera uncia) and wolves (Canis lupus). We interviewed 381 individuals from 24 villages within 6 study sites across the high‐elevation Spiti Valley in the Indian Trans‐Himalaya. We gathered information on key explanatory variables that together captured variation in individual and village‐level socioeconomic factors. We used hierarchical linear models to examine how the effect of these factors on human attitudes changed with the scale of analysis from the individual to the community. Factors significant at the individual level were gender, education, and age of the respondent (for wolves and snow leopards), number of income sources in the family (wolves), agricultural production, and large‐bodied livestock holdings (snow leopards). At the community level, the significant factors included the number of smaller‐bodied herded livestock killed by wolves and mean agricultural production (wolves) and village size and large livestock holdings (snow leopards). Our results show that scaling up from the individual to higher levels of social organization can highlight important factors that influence attitudes of people toward wildlife and toward formal conservation efforts in general. Such scale‐specific information can help managers apply conservation measures at appropriate scales. Our results reiterate the need for conflict management programs to be multipronged. Factores Multi‐Escala que Afectan las Actitudes Humanas hacia Leopardos de las Nieves y Lobos     

Modeling changes in the coastal ecosystem of the Pearl River Estuary from 1981 to 1998

The coastal ecosystem of the Pearl River Estuary (PRE) has been overfished and received a high level of combined pollution since the 1980s. Ecopath with Ecosim was used to construct two ecosystem models (for 1981 and 1998) to characterize the food web structure and functioning of the ecosystem. Pedigree work and simple sensitivity analysis were carried out to evaluate the quality of data and the uncertainty of the models. The two models seem reliable with regards to input data of good quality. Comparing the variations of outputs of these two models aimed to facilitate assessment of changes of the ecosystem during the past two decades.The trophic structure of the ecosystem has changed with an increase in the biomass proportion of lower trophic level (TL) organisms and a decrease in top predator biomass proportion. All the indices of ecosystem maturity examined show that the system was in a more mature condition in 1981 than in 1998, although the system has been in a condition of stress due to anthropogenic disturbances, such as environmental pollution and habitat destruction since 1981. The ecosystem was aggregated into six and seven integral TLs in 1981 and 1998, respectively, using the trophic aggregation routine of Ecopath. Most of the total system biomass and catch took place at TL II and III in both years. But the distribution of the total system biomass and catch at different TLs changed with decreasing proportions in higher TLs in 1998. The mean transfer efficiency was 9.1% and 10.2% in 1981 and 1998, respectively.Comparative network analysis allowed quantification of the importance of direct and indirect trophic interactions among functional groups. Moreover, a method derived from the mixed trophic impact (MTI) analysis allowed estimating importance of groups in terms of “keystoneness” and identifying the keystone species in the two models over the past two decades. The results indicate that there were no clear keystone species in 1998 but two keystone species at medium trophic levels were identified in 1981. Moreover, organisms located at low trophic levels such as phytoplankton, zooplankton and benthic invertebrates were identified to have relatively high keystoneness in the ecosystem.     

Validity of the Prey‐Trap Hypothesis for Carnivore‐Ungulate Interactions at Wildlife‐Crossing Structures

Abstract: Wildlife‐exclusion fencing and wildlife‐crossing structures (e.g., underpasses and overpasses) are becoming increasingly common features of highway projects around the world. The prey‐trap hypothesis posits that predators exploit crossing structures to detect and capture prey. The hypothesis predicts that predation events occur closer to a highway after the construction of fences and crossing structures and that prey species’ use of crossings increases the probability that predators will attack prey. We examined interactions between ungulates and large carnivores at 28 wildlife crossing structures along 45 km of the Trans‐Canada Highway in Banff National Park, Alberta. We obtained long‐term records of locations where ungulates were killed (kill sites) before and after crossing structures were built. We also placed remote, motion‐triggered cameras at two crossing structures to monitor predator behavior following ungulate passage through the structure. The proximity of ungulate kill sites to the highway was similar before and after construction of fencing and crossing structures. We found only five kill sites near crossing structures after more than 32,000 visits over 13 years. We found no evidence that predator behavior at crossing structures is affected by prey movement. Our results suggest that interactions between large mammals and their prey at wildlife‐crossing structures in Banff National Park are not explained by the prey‐trap hypothesis.     

Water tables constrain height recovery of willow on Yellowstone's northern range.

Excessive levels of herbivory may disturb ecosystems in ways that persist even when herbivory is moderated. These persistent changes may complicate efforts to restore ecosystems affected by herbivores. Willow (Salix spp.) communities within the northern range in Yellowstone National Park have been eliminated or degraded in many riparian areas by excessive elk (Cervus elaphus L.) browsing. Elk browsing of riparian willows appears to have diminished following the reintroduction of wolves (Canis lupis L.), but it remains uncertain whether reduced herbivory will restore willow communities. The direct effects of elk browsing on willows have been accompanied by indirect effects from the loss of beaver (Castor canadensis Kuhl) activity, including incision of stream channels, erosion of fine sediments, and lower water tables near streams historically dammed by beaver. In areas where these changes have occurred, lowered water tables may suppress willow height even in the absence of elk browsing. We conducted a factorial field experiment to understand willow responses to browsing and to height of water tables. After four years of protection from elk browsing, willows with ambient water tables averaged only 106 cm in height, with negligible height gain in two of three study species during the last year of the experiment. Willows that were protected from browsing and had artificially elevated water tables averaged 147 cm in height and gained 19 cm in the last year of the experiment. In browsed plots, elevated water tables doubled height gain during a period of slightly reduced browsing pressure. We conclude that water availability mediates the rate of willow height gain and may determine whether willows grow tall enough to escape the browse zone of elk and gain resistance to future elk browsing. Consequently, in areas where long-term beaver absence has resulted in incised stream channels and low water tables, a reduction in elk browsing alone may not be sufficient for recovery of tall willow stands. Because tall willow stems are important elements of habitat for beaver, mitigating water table decline may be necessary in these areas to promote recovery of historical willow-beaver mutualisms.     

Values Associated with Management of Yellowstone Cutthroat Trout in Yellowstone National Park

Recent emphasis on a holistic view of natural systems and their management is associated with a growing appreciation of the role of human values in these systems. In the past, resource management has been perceived as a dichotomy between extraction (harvest) and nonconsumptive use, but this appears to be an oversimplified view of natural-cultural systems. The recreational fishery for Yellowstone cutthroat trout ( Oncorhynchus clarki bouvieri ) in Yellowstone National Park is an example of the effects of management on a natural-cultural system. Although angler harvest has been drastically reduced or prohibited, the recreational value of Yellowstone cutthroat trout estimated by angling factors (such as landing rate or size) ranks above that of all other sport species in Yellowstone National Park. To maintain an indigenous fishery resource of this quality with hatchery propagation is not economically or technically feasible. Nonconsumptive uses of the Yellowstone cutthroat trout including fish-watching and intangible values, such as existence demand, provide additional support for protection of wild Yellowstone cutthroat trout populations. A management strategy that reduces resource extraction has provided a means to sustain a quality recreational fishery while enhancing values associated with the protection of natural systems.     

Dynamics of Hybridization and Introgression in Red Wolves and Coyotes

Abstract:  Hybridization and introgression are significant causes of endangerment in many taxa and are considered the greatest biological threats to the reintroduced population of red wolves ( Canis rufus ) in North Carolina (U.S.A.). Little is known, however, about these processes in red wolves and coyotes ( C. latrans ). We used individual-based simulations to examine the process of hybridization and introgression between these species. Under the range of circumstances we considered, red wolves in colonizing and established populations were quickly extirpated, persisted near the carrying capacity, or had intermediate outcomes. Sensitivity analyses suggested that the probabilities of quasi extinction and persistence of red wolves near the carrying capacity were most affected by the strength of two reproductive barriers: red wolf challenges and assortative mating between red wolves and coyotes. Because model parameters for these barriers may be difficult to estimate, we also sought to identify other predictors of red wolf population fate. The proportion of pure red wolves in the population was a strong predictor of the future probabilities of red wolf quasi extinction and persistence. Finally, we examined whether sterilization can be effective in minimizing introgression while allowing the reintroduced red wolf population to grow. Our results suggest sterilization can be an effective short-term strategy to reduce the likelihood of extirpation in colonizing populations of red wolves. Whether red wolf numbers are increased by sterilization depends on the level of sterilization effort and the acting reproductive barriers. Our results provide an outline of the conditions likely required for successful reestablishment and long-term maintenance of populations of wild red wolves in the presence of coyotes. Our modeling approach may prove generally useful in providing insight into situations involving complex species interactions when data are few.     

Moral dimensions of human–wildlife conflict

Despite increasing support for conservation globally, controversy over specific conservation policies persists among diverse stakeholders. Investigating the links between morals in relation to conservation can help increase understanding about why humans support or oppose policy, especially related to human–wildlife conflict or human conflict over wildlife. Yet the moral dimension of human–wildlife conflict has mostly gone unconsidered and unmeasured; thus, policy and programmatic efforts to reduce controversy may be missing a key part of the equation. We conducted a web‐based survey (n = 1239 respondents) in Michigan (U.S.A.) to investigate cognitive and emotional influences on the value–behavior relationship. Respondents were identified by their interest and involvement in Michigan wolf management. The survey consisted of questions about values, emotions, cognitions, and behaviors relative to wolves in Michigan. We used path analysis to explore whether emotions and cognitions mediated the relationship between value and behavior. Most respondents attributed intrinsic value to wolves (n = 734) and all life (n = 773) and engaged in behaviors that benefited wolf populations and ecosystems regardless of stakeholder group (e.g., environmentalist, farmer). Attributing intrinsic value to wolves was positively related to favorable emotions toward wolves and cognitive assessments that hunting and trapping of wolves is unacceptable. Despite similarities in attribution of intrinsic value, groups differed in emotions and cognitions about wolf hunting. These differences provide a useful way to predict stakeholder behavior. Our findings may inform interventions aimed at increasing support for wolf management policies and positive interactions among stakeholders and wildlife. Leveraging agreement over intrinsic value may foster cooperation among stakeholders and garner support for controversial conservation policy.     

On the Origin of Brucellosis in Bison of Yellowstone National Park: A Review

Brucellosis caused by Brucella abortus occurs in the free-ranging bison ( Bison bison ) of Yellowstone and Wood Buffalo National Parks and in elk ( Cervus elaphus ) of the Greater Yellowstone Area. As a result of nationwide bovine brucellosis eradication programs, states and provinces proximate to the national parks are considered free of bovine brucellosis. Thus, increased attention has been focused on the wildlife within these areas as potential reservoirs for transmission to cattle. Because the national parks are mandated as natural areas, the question has been raised as to whether Brucella abortus is endogenous or exogenous to bison, particularly for Yellowstone National Park. We synthesized diverse lines of inquiry, including the evolutionary history of both bison and Brucella , wild animals as Brucella hosts, biochemical and genetic information, behavioral characteristics of host and organism, and area history to develop an evaluation of the question for the National Park Service. All lines of inquiry indicated that the organism was introduced to North America with cattle, and that the introduction into the Yellowstone bison probably was directly from cattle shortly before 1917. Fistulous withers of horses was a less likely possibility. Elk on winter feedgrounds south of Yellowstone National Park apparently acquired the disease directly from cattle. Bison presently using Grand Teton National Park probably acquired brucellosis from feedground elk.