Demographic Connectivity for Ursid Populations at Wildlife Crossing Structures in Banff National Park

Wildlife crossing structures are one solution to mitigating the fragmentation of wildlife populations caused by roads, but their effectiveness in providing connectivity has only been superficially evaluated. Hundreds of grizzly (Ursus arctos) and black bear (Ursus americanus) passages through under and overpasses have been recorded in Banff National Park, Alberta, Canada. However, the ability of crossing structures to allow individual and population‐level movements across road networks remains unknown. In April 2006, we initiated a 3‐year investigation into whether crossing structures provide demographic connectivity for grizzly and black bears in Banff National Park. We collected hair with multiple noninvasive methods to obtain genetic samples from grizzly and black bears around the Bow Valley. Our objectives were to determine the number of male and female grizzly and black bears that use crossing structures; examine spatial and temporal patterns of crossings; and estimate the proportions of grizzly and black bear populations in the Bow Valley that use crossing structures. Fifteen grizzly (7 female, 8 male) and 17 black bears (8 female, 9 male) used wildlife crossing structures. The number of individuals detected at wildlife crossing structures was highly correlated with the number of passages in space and time. Grizzly bears used open crossing structures (e.g., overpasses) more often than constricted crossings (e.g., culverts). Peak use of crossing structures for both bear species occurred in July, when high rates of foraging activity coincide with mating season. We compared the number of bears that used crossings with estimates of population abundance from a related study and determined that substantial percentages of grizzly (15.0% in 2006, 19.8% in 2008) and black bear (17.6% in 2006, 11.0% in 2008) populations used crossing structures. On the basis of our results, we concluded wildlife crossing structures provide demographic connectivity for bear populations in Banff National Park. Conectividad Demográfica para Poblaciones de Úrsidos en Estructuras para Cruce de Vida Silvestre en el Parque Nacional Banff     

Factors Influencing the Effectiveness of Wildlife Underpasses in Banff National Park, Alberta, Canada

Abstract: Wildlife crossing structures are intended to increase permeability and habitat connectivity across roads. Few studies, however, have assessed the effectiveness of these mitigation measures in a multispecies or community level context. We used a null model to test whether wildlife crossing structures serve large mammal species equally or whether such structures limit habitat connectivity across roads in species-specific ways. We also modeled species responses to 14 variables related to underpass structure, landscape features, and human activity. Species performance ratios (observed crossing frequency to expected crossing frequency) were evaluated for four large carnivore and three ungulate species in 11 underpass structures in Banff National Park, Alberta, Canada. Observed crossing frequencies were collected in 35 months of underpass monitoring. Expected frequencies were developed from three independent models: radio telemetry, pellet counts, and habitat-suitability indices. The null model showed that species responded to underpasses differently. In the presence of human activity carnivores were less likely to use underpasses than were ungulates. Apart from human activity, carnivore performance ratios were better correlated to landscape variables, and ungulate performance ratios were better correlated to structural variables. We suggest that future underpasses designed around topography, habitat quality, and location will be minimally successful if human activity is not managed.     

Factors Mediating Co‐Occurrence of an Economically Valuable Introduced Fish and Its Native Frog Prey

Habitat characteristics mediate predator–prey coexistence in many ecological systems but are seldom considered in species introductions. When economically important introduced predators are stocked despite known negative impacts on native species, understanding the role of refuges, landscape configurations, and community interactions can inform habitat management plans. We measured these factors in basins with introduced trout (Salmonidae) and the Cascades frog (Rana cascadae) to determine, which are responsible for observed patterns of co‐occurrence of this economically important predator and its native prey. Large, vegetated shallows were strongly correlated to co‐occurrence, and R. cascadae larvae occur in shallower water when fish are present, presumably to escape predation. The number of nearby breeding sites of R. cascadae was also correlated to co‐occurrence, but only when the western toad (Anaxyrus boreas) was present. Because A. boreas larvae are unpalatable to fish and resemble R. cascadae, they may provide protection from trout via Batesian mimicry. Although rescue‐effect dispersal from nearby populations may maintain co‐occurrence, within‐lake factors proved more important for predicting co‐occurrence. Learning which factors allow co‐occurrence between economically important introduced species and their native prey enables managers to make better‐informed stocking decisions. Factores que Median la Co‐Ocurrencia de un Pez Introducido con Valor Económico y su Presa, una Rana Nativa     

Minimizing predation risk in a landscape of multiple predators: effects on the spatial distribution of African ungulates

Studies that focus on single predator-prey interactions can be inadequate for understanding antipredator responses in multi-predator systems. Yet there is still a general lack of information about the strategies of prey to minimize predation risk from multiple predators at the landscape level. Here we examined the distribution of seven African ungulate species in the fenced Karongwe Game Reserve (KGR), South Africa, as a function of predation risk from all large carnivore species (lion, leopard, cheetah, African wild dog, and spotted hyena). Using observed kill data, we generated ungulate-specific predictions of relative predation risk and of riskiness of habitats. To determine how ungulates minimize predation risk at the landscape level, we explicitly tested five hypotheses consisting of strategies that reduce the probability of encountering predators, and the probability of being killed. All ungulate species avoided risky habitats, and most selected safer habitats, thus reducing their probability of being killed. To reduce the probability of encountering predators, most of the smaller prey species (impala, warthog, waterbuck, kudu) avoided the space use of all predators, while the larger species (wildebeest, zebra, giraffe) only avoided areas where lion and leopard space use were high. The strength of avoidance for the space use of predators generally did not correspond to the relative predation threat from those predators. Instead, ungulates used a simpler behavioral rule of avoiding the activity areas of sit-and-pursue predators (lion and leopard), but not those of cursorial predators (cheetah and African wild dog). In general, selection and avoidance of habitats was stronger than avoidance of the predator activity areas. We expect similar decision rules to drive the distribution pattern of ungulates in other African savannas and in other multi-predator systems, especially where predators differ in their hunting modes.     

Identifying impediments to long‐distance mammal migrations

In much of the world, the persistence of long‐distance migrations by mammals is threatened by development. Even where human population density is relatively low, there are roads, fencing, and energy development that present barriers to animal movement. If we are to conserve species that rely on long‐distance migration, then it is critical that we identify existing migration impediments. To delineate stopover sites associated with anthropogenic development, we applied Brownian bridge movement models to high‐frequency locations of pronghorn (Antilocapra americana) in the Greater Yellowstone Ecosystem. We then used resource utilization functions to assess the threats to long‐distance migration of pronghorn that were due to fences and highways. Migrating pronghorn avoided dense developments of natural gas fields. Highways with relatively high volumes of traffic and woven‐wire sheep fence acted as complete barriers. At crossings with known migration bottlenecks, use of high?quality forage and shrub habitat by pronghorn as they approached the highway was lower than expected based on availability of those resources. In contrast, pronghorn consistently utilized high?quality forage close to the highway at crossings with no known migration bottlenecks. Our findings demonstrate the importance of minimizing development in migration corridors in the future and of mitigating existing pressure on migratory animals by removing barriers, reducing the development footprint, or installing crossing structures. Identificación de los Impedimentos para las Migraciones de Larga Distancia de Mamíferos     

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.     

Effectiveness of Predator Removal for Enhancing Bird Populations

Abstract: Predation pressure on vulnerable bird species has made predator control an important issue for international nature conservation. Predator removal by culling or translocation is controversial, expensive, and time‐consuming, and results are often temporary. Thus, it is important to assess its effectiveness from all available evidence. We used explicit systematic review methodology to determine the impact of predator removal on four measurable responses in birds: breeding performance (hatching success and fledging success) and population size (breeding and postbreeding). We used meta‐analysis to summarize results from 83 predator removal studies from six continents. We also investigated whether characteristics of the prey, predator species, location, and study methodology explained heterogeneity in effect sizes. Removing predators increased hatching success, fledging success, and breeding populations. Removing all predator species achieved a significantly larger increase in breeding population than removing only a subset. Postbreeding population size was not improved on islands, or overall, but did increase on mainlands. Heterogeneity in effect sizes for the four population parameters was not explained by whether predators were native or introduced; prey were declining, migratory, or game species; or by the study methodology. Effect sizes for fledging success were smaller for ground‐nesting birds than those that nest elsewhere, but the difference was not significant. We conclude that current evidence indicates that predator removal is an effective strategy for the conservation of vulnerable bird populations. Nevertheless, the ethical and practical problems associated with predator removal may lead managers to favor alternative, nonlethal solutions. Research is needed to provide and synthesize data to determine whether these are effective management practices for future policies on bird conservation.     

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.     

Drivers of Seabird Population Recovery on New Zealand Islands after Predator Eradication

Eradication of introduced mammalian predators from islands has become increasingly common, with over 800 successful projects around the world. Historically, introduced predators extirpated or reduced the size of many seabird populations, changing the dynamics of entire island ecosystems. Although the primary outcome of many eradication projects is the restoration of affected seabird populations, natural population responses are rarely documented and mechanisms are poorly understood. We used a generic model of seabird colony growth to identify key predictor variables relevant to recovery or recolonization. We used generalized linear mixed models to test the importance of these variables in driving seabird population responses after predator eradication on islands around New Zealand. The most influential variable affecting recolonization of seabirds around New Zealand was the distance to a source population, with few cases of recolonization without a source population ≤25 km away. Colony growth was most affected by metapopulation status; there was little colony growth in species with a declining status. These characteristics may facilitate the prioritization of newly predator‐free islands for active management. Although we found some evidence documenting natural recovery, generally this topic was understudied. Our results suggest that in order to guide management strategies, more effort should be allocated to monitoring wildlife response after eradication. Conductores de la Recuperación de Poblaciones de Aves Marinas en Islas de Nueva Zelanda después de la Erradicación de Depredadores     

Ungulate Traffic Collisions in Europe

The expansion of highways and roads can fragment natural habitats and thus decrease the viability of ungulate subpopulations. It can also increase the number of vehicle collisions with wildlife. Although collisions apparently contribute to only a minor part of the annual mortality for most ungulate populations, they have become a serious road-safety problem in Europe, the United States, and Japan. To better understand this threat to biodiversity and road safety, we reviewed European and, secondarily, North-American and Japanese literature on ungulate traffic collisions. In contrast to the results of some long-term studies, we argue that the relationship suggested between the number of road kills and traffic volume is confounded by population dynamics, changes in traffic volume, and sampling intensity. Although sexes may run distinct seasonal risks of collision, the age and sex composition of road kills reflect population structure in the field. We also argue that observed seasonal and daily patterns in the number of road kills, related to life-history features of the species involved, should form the template for solutions to the problem. We found no strong evidence of the effects of permanent warning signs, 90° light mirrors, scent, or acoustic fencing on the number of kills per crossing. To reduce the risk of ungulate traffic collisions, we recommend a combination of fencing and wildlife passages for roads and railroads that combine high traffic volume with high speed. For secondary roads we recommend seasonal application of intermittently lighted warning signs, triggered if possible by the ungulates. We emphasize the need for educational programs.     

Evaluating the impact of caribou habitat restoration on predator and prey movement

Fragmentation of the boreal forest by linear features, including seismic lines, has destabilized predator–prey dynamics, resulting in the decline of woodland caribou (Rangifer tarandus caribou) populations. Restoration of human-altered habitat has therefore been identified as a critical management tool for achieving self-sustaining woodland caribou populations. However, only recently has testing of the response of caribou and other wildlife to restoration activities been conducted. Early work has centered around assessing changes in wildlife use of restored seismic lines. We evaluated whether restoration reduces the movement rates of predators and their associated prey, which is expected to decrease predator hunting efficiency and ultimately reduce caribou mortality. We developed a new method for using cameras to measure fine-scale movement by measuring speed as animals traveled between cameras in an array. We used our method to quantify speed of caribou, moose (Alces alces), bears (Ursus americanus), and wolves (Canis lupus) on treated (restored) and untreated seismic lines. Restoration treatments reduced travel speeds along seismic lines of wolves by 1.38 km/h, bears by 0.55 km/h, and caribou by 1.57 km/h, but did not reduce moose travel speeds. Reduced predator and caribou speeds on treated seismic lines are predicted to decrease encounter rates between predators and caribou and thus lower caribou kill rates. However, further work is needed to determine whether reduced movement rates result in reduced encounter rates with prey, and ultimately reduced caribou mortality.     

The Paradox of the Long‐Term Positive Effects of a North American Crayfish on a European Community of Predators

Abstract: Invasions of non‐native species are one of the major causes of losses of native species. In some cases, however, non‐natives may also have positive effects on native species. We investigated the potential facilitative effects of the North American red swamp crayfish (Procambarus clarkii) on the community of predators in southwestern Spain. To do so, we examined the diets of predators in the area and their population trends since introduction of the crayfish. Most predator species consumed red swamp crayfish, which sometimes occurred in over 50% of their diet samples. Moreover, the abundance of species preying on crayfish increased significantly in the area as opposed to the abundance of herbivores and to predator populations in other areas of Europe, where those predators are even considered threatened. Thus, we report the first case in which one non‐native species is both beneficial because it provides prey for threatened species and detrimental because it can drive species at lower trophic levels to extinction. Increases in predator numbers that are associated with non‐native species of prey, especially when some of these predators are also invasive non‐natives, may increase levels of predation on other species and produce cascading effects that threaten native biota at longer temporal and larger spatial scales. Future management plans should include the complexity of interactions between invasive non‐natives and the entire native community, the feasibility of successful removal of non‐native species, and the potential social and economic interests in the area.     

Trophic Cascades Following the Disease‐Induced Decline of an Apex Predator,the Tasmanian Devil

As apex predators disappear worldwide, there is escalating evidence of their importance in maintaining the integrity and diversity of the ecosystems they inhabit. The largest extant marsupial carnivore, the Tasmanian devil (Sarcophilus harrisii) is threatened with extinction from a transmissible cancer, devil facial tumor disease (DFTD). The disease, first observed in 1996, has led to apparent population declines in excess of 95% in some areas and has spread to more than 80% of their range. We analyzed a long‐term Tasmania‐wide data set derived from wildlife spotlighting surveys to assess the effects of DFTD‐induced devil decline on populations of other mammals and to examine the relative strength of top–down and bottom–up control of mesopredators between 2 regions with different environmental conditions. Collection of the data began >10 years before DFTD was first observed. A decrease in devil populations was immediate across diseased regions following DFTD arrival, and there has been no indication of population recovery. Feral cats (Felis catus) increased in areas where the disease was present the longest, and feral cat occurrence was significantly and negatively associated with devils. The smallest mesopredator, the eastern quoll (Dasyurus viverrinus), declined rapidly following DFTD arrival. This result suggests the species was indirectly protected by devils through the suppression of larger predators. Rainfall deficiency was also a significant predictor of their decline. Environmental variables determined the relative importance of top–down control in the population regulation of mesopredators. In landscapes of low rainfall and relatively higher proportions of agriculture and human settlement, top–down forces were dampened and bottom–up forces had the most effect on mesopredators. For herbivore prey species, there was evidence of population differences after DFTD arrival, but undetected environmental factors had greater effects. The unique opportunity to assess population changes over extensive temporal and spatial scales following apex predator loss further demonstrated their role in structuring ecosystems and of productivity in determining the strength of top–down control. Cascadas Tróficas Después de la Declinación Inducida por Enfermedad de un Depredador Apical, el Demonio de Tasmania     

Impact of conservation areas on trophic interactions between apex predators and herbivores on coral reefs

Apex predators are declining at alarming rates due to exploitation by humans, but we have yet to fully discern the impacts of apex predator loss on ecosystem function. In a management context, it is critically important to clarify the role apex predators play in structuring populations of lower trophic levels. Thus, we examined the top‐down influence of reef sharks (an apex predator on coral reefs) and mesopredators on large‐bodied herbivores. We measured the abundance, size structure, and biomass of apex predators, mesopredators, and herbivores across fished, no‐take, and no‐entry management zones in the Great Barrier Reef Marine Park, Australia. Shark abundance and mesopredator size and biomass were higher in no‐entry zones than in fished and no‐take zones, which indicates the viability of strictly enforced human exclusion areas as tools for the conservation of predator communities. Changes in predator populations due to protection in no‐entry zones did not have a discernible influence on the density, size, or biomass of different functional groups of herbivorous fishes. The lack of a relationship between predators and herbivores suggests that top‐down forces may not play a strong role in regulating large‐bodied herbivorous coral reef fish populations. Given this inconsistency with traditional ecological theories of trophic cascades, trophic structures on coral reefs may need to be reassessed to enable the establishment of appropriate and effective management regimes. El Impacto de las Áreas de Conservación sobre las Interacciones Tróficas entre los Depredadores Dominantes y los Herbívoros en los Arrecifes de Coral     

Poaching Risks in Community‐Based Natural Resource Management

Poaching can disrupt wildlife‐management efforts in community‐based natural resource management systems. Monitoring, estimating, and acquiring data on poaching is difficult. We used local‐stakeholder knowledge and poaching records to rank and map the risk of poaching incidents in 2 areas where natural resources are managed by community members in Caprivi, Namibia. We mapped local stakeholder perceptions of the risk of poaching, risk of wildlife damage to livelihoods, and wildlife distribution and compared these maps with spatially explicit records of poaching events. Recorded poaching events and stakeholder perceptions of where poaching occurred were not spatially correlated. However, the locations of documented poaching events were spatially correlated with areas that stakeholders perceived wildlife as a threat to their livelihoods. This result suggests poaching occurred in response to wildlife damage occurred. Local stakeholders thought that wildlife populations were at high risk of being poached and that poaching occurred where there was abundant wildlife. These findings suggest stakeholders were concerned about wildlife resources in their community and indicate a need for integrated and continued monitoring of poaching activities and further interventions at the wildlife‐agricultural interface. Involving stakeholders in the assessment of poaching risks promotes their participation in local conservation efforts, a central tenet of community‐based management. We considered stakeholders poaching informants, rather than suspects, and our technique was spatially explicit. Different strategies to reduce poaching are likely needed in different areas. For example, interventions that reduce human‐wildlife conflict may be required in residential areas, and increased and targeted patrolling may be required in more remote areas. Stakeholder‐generated maps of human‐wildlife interactions may be a valuable enforcement and intervention support tool. Riesgos de Cacería Furtiva en el Manejo de Recursos Naturales Basado en Comunidades     

An interdisciplinary review of current and future approaches to improving human–predator relations

In a world of shrinking habitats and increasing competition for natural resources, potentially dangerous predators bring the challenges of coexisting with wildlife sharply into focus. Through interdisciplinary collaboration among authors trained in the humanities, social sciences, and natural sciences, we reviewed current approaches to mitigating adverse human–predator encounters and devised a vision for future approaches to understanding and mitigating such encounters. Limitations to current approaches to mitigation include too much focus on negative impacts; oversimplified equating of levels of damage with levels of conflict; and unsuccessful technical fixes resulting from failure to engage locals, address hidden costs, or understand cultural (nonscientific) explanations of the causality of attacks. An emerging interdisciplinary literature suggests that to better frame and successfully mitigate negative human–predator relations conservation professionals need to consider dispensing with conflict as the dominant framework for thinking about human–predator encounters; work out what conflicts are really about (they may be human–human conflicts); unravel the historical contexts of particular conflicts; and explore different cultural ways of thinking about animals. The idea of cosmopolitan natures may help conservation professionals think more clearly about human–predator relations in both local and global context. These new perspectives for future research practice include a recommendation for focused interdisciplinary research and the use of new approaches, including human‐animal geography, multispecies ethnography, and approaches from the environmental humanities notably environmental history. Managers should think carefully about how they engage with local cultural beliefs about wildlife, work with all parties to agree on what constitutes good evidence, develop processes and methods to mitigate conflicts, and decide how to monitor and evaluate these. Demand for immediate solutions that benefit both conservation and development favors dispute resolution and technical fixes, which obscures important underlying drivers of conflicts. If these drivers are not considered, well‐intentioned efforts focused on human–wildlife conflicts will fail.     

Defining ecologically relevant scales for spatial protection with long‐term data on an endangered seabird and local prey availability

Human activities are important drivers of marine ecosystem functioning. However, separating the synergistic effects of fishing and environmental variability on the prey base of nontarget predators is difficult, often because prey availability estimates on appropriate scales are lacking. Understanding how prey abundance at different spatial scales links to population change can help integrate the needs of nontarget predators into fisheries management by defining ecologically relevant areas for spatial protection. We investigated the local population response (number of breeders) of the Bank Cormorant (Phalacrocorax neglectus), a range‐restricted endangered seabird, to the availability of its prey, the heavily fished west coast rock lobster (Jasus lalandii). Using Bayesian state‐space modeled cormorant counts at 3 colonies, 22 years of fisheries‐independent data on local lobster abundance, and generalized additive modeling, we determined the spatial scale pertinent to these relationships in areas with different lobster availability. Cormorant numbers responded positively to lobster availability in the regions with intermediate and high abundance but not where regime shifts and fishing pressure had depleted lobster stocks. The relationships were strongest when lobsters 20–30 km offshore of the colony were considered, a distance greater than the Bank Cormorant's foraging range when breeding, and may have been influenced by prey availability for nonbreeding birds, prey switching, or prey ecology. Our results highlight the importance of considering the scale of ecological relationships in marine spatial planning and suggest that designing spatial protection around focal species can benefit marine predators across their full life cycle. We propose the precautionary implementation of small‐scale marine protected areas, followed by robust assessment and adaptive‐management, to confirm population‐level benefits for the cormorants, their prey, and the wider ecosystem, without negative impacts on local fisheries.     

Permeability of Roads to Movement of Scrubland Lizards and Small Mammals

A primary objective of road ecology is to understand and predict how roads affect connectivity of wildlife populations. Road avoidance behavior can fragment populations, whereas lack of road avoidance can result in high mortality due to wildlife‐vehicle collisions. Many small animal species focus their activities to particular microhabitats within their larger habitat. We sought to assess how different types of roads affect the movement of small vertebrates and to explore whether responses to roads may be predictable on the basis of animal life history or microhabitat preferences preferences. We tracked the movements of fluorescently marked animals at 24 sites distributed among 3 road types: low‐use dirt, low‐use secondary paved, and rural 2‐lane highway. Most data we collected were on the San Diego pocket mouse (Chaetodipus fallax), cactus mouse (Peromyscus eremicus), western fence lizard (Sceloporus occidentalis), orange‐throated whiptail (Aspidoscelis hyperythra), Dulzura kangaroo rat (Dipodomys simulans) (dirt, secondary paved), and deer mouse (Peromyscus maniculatus) (highway only). San Diego pocket mice and cactus mice moved onto dirt roads but not onto a low‐use paved road of similar width or onto the highway, indicating they avoid paved road substrate. Both lizard species moved onto the dirt and secondary paved roads but avoided the rural 2‐lane rural highway, indicating they may avoid noise, vibration, or visual disturbance from a steady flow of traffic. Kangaroo rats did not avoid the dirt or secondary paved roads. Overall, dirt and secondary roads were more permeable to species that prefer to forage or bask in open areas of their habitat, rather than under the cover of rocks or shrubs. However, all study species avoided the rural 2‐lane highway. Our results suggest that microhabitat use preferences and road substrate help predict species responses to low‐use roads, but roads with heavy traffic may deter movement of a much wider range of small animal species.     

Global patterns and trends in human–wildlife conflict compensation

Human–wildlife conflict is a major conservation challenge, and compensation for wildlife damage is a widely used economic tool to mitigate this conflict. The effectiveness of this management tool is widely debated. The relative importance of factors associated with compensation success is unclear, and little is known about global geographic or taxonomic differences in the application of compensation programs. We reviewed research on wildlife‐damage compensation to determine geographic and taxonomic gaps, analyze patterns of positive and negative comments related to compensation, and assess the relative magnitude of global compensation payments. We analyzed 288 publications referencing wildlife compensation and identified 138 unique compensation programs. These publications reported US$222 million (adjusted for inflation) spent on compensation in 50 countries since 1980. Europeans published the most articles, and compensation funding was highest in Europe, where depredation by wolves and bears was the most frequently compensated damage. Authors of the publications we reviewed made twice as many negative comments as positive comments about compensation. Three‐quarters of the negative comments related to program administration. Conversely, three‐quarters of the positive comments related to program outcomes. The 3 most common suggestions to improve compensation programs included requiring claimants to employ damage‐prevention practices, such as improving livestock husbandry or fencing of crops to receive compensation (n = 25, 15%); modifying ex post compensation schemes to some form of outcome‐based performance payment (n = 21, 12%); and altering programs to make compensation payments more quickly (n = 14, 8%). We suggest that further understanding of the strengths and weaknesses of compensation as a conflict‐mitigation tool will require more systematic evaluation of the factors driving these opinions and that differentiating process and outcomes and understanding linkages between them will result in more fruitful analyses and ultimately more effective conflict mitigation.     

Ensemble ecosystem modeling for predicting ecosystem response to predator reintroduction

Introducing a new or extirpated species to an ecosystem is risky, and managers need quantitative methods that can predict the consequences for the recipient ecosystem. Proponents of keystone predator reintroductions commonly argue that the presence of the predator will restore ecosystem function, but this has not always been the case, and mathematical modeling has an important role to play in predicting how reintroductions will likely play out. We devised an ensemble modeling method that integrates species interaction networks and dynamic community simulations and used it to describe the range of plausible consequences of 2 keystone‐predator reintroductions: wolves (Canis lupus) to Yellowstone National Park and dingoes (Canis dingo) to a national park in Australia. Although previous methods for predicting ecosystem responses to such interventions focused on predicting changes around a given equilibrium, we used Lotka–Volterra equations to predict changing abundances through time. We applied our method to interaction networks for wolves in Yellowstone National Park and for dingoes in Australia. Our model replicated the observed dynamics in Yellowstone National Park and produced a larger range of potential outcomes for the dingo network. However, we also found that changes in small vertebrates or invertebrates gave a good indication about the potential future state of the system. Our method allowed us to predict when the systems were far from equilibrium. Our results showed that the method can also be used to predict which species may increase or decrease following a reintroduction and can identify species that are important to monitor (i.e., species whose changes in abundance give extra insight into broad changes in the system). Ensemble ecosystem modeling can also be applied to assess the ecosystem‐wide implications of other types of interventions including assisted migration, biocontrol, and invasive species eradication.