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Land use and climate change alter species distributions worldwide, and detecting and understanding how species ranges shift can facilitate conservation planning and action. Following extirpation from most of the contiguous United States, gray wolves (Canis lupus) have partially recolonized former range in the western Great Lakes region, but it is unknown how land use and climate change may alter amounts of wolf habitat. Using wolf observation data collected during winters 2017–2020 in Minnesota, Wisconsin, and Michigan, we created ensemble models to predict how land use and climate change may affect the amount of wolf habitat within these states. A projection model for the western Great Lakes region suggested three of four scenarios of land use and climate change will lead to 9%–35% increases in wolf habitat, while a solely climate‐based projection model supported our expectation that changes in climate, in isolation, will have limited effect on current wolf range. Our results support stable or increasing amounts of wolf habitat in the western Great Lakes region during the 21st century, suggesting limited or no adverse effects on the current distribution or further recolonization of wolves. Our findings can inform policy development regarding wolf conservation and identify areas where recolonization is plausible, thus where promoting human–wolf coexistence is most pertinent.

Statistical population reconstruction (SPR) models have emerged as a robust and versatile framework for estimating the demographic dynamics of harvested wildlife populations using commonly collected age‐at‐harvest and catch‐effort data. Although numerous studies have suggested that higher interannual variability in catch effort may improve the accuracy and precision of reconstructed estimates, particularly in the absence of auxiliary data on annual abundance or survival, the extent and magnitude of these effects has not been explored. We examined the influence of catch‐effort variability, as measured by the ratio between years of highest and lowest effort, on the relative absolute deviation of reconstructed estimates of population abundance, as well as on the actual percent coverage and width of the corresponding confidence intervals. We used a Monte Carlo simulation to generate catch‐effort data with different levels of variability for populations experiencing a wide range of demographic and harvest conditions. For similar amounts of age‐at‐harvest data, using catch‐effort data with higher interannual variability resulted in reconstructed estimates of annual abundance that had significantly lower deviations from reality, better coverage, and narrower confidence intervals (as measured by the margin of error). These improvements were consistent and linear at low to medium levels of catch‐effort variability, but leveled off and became substantially less pronounced at higher levels. We found that the inclusion of auxiliary data largely mediated this relationship, although higher catch‐effort variability still resulted in more accurate and precise estimates of annual abundance even when these data were included. Our research highlights the need to include a thorough investigation of the available catch‐effort data alongside the established practices of assessing the number of years of available data, the average number of animals harvested each year, and the availability of auxiliary data from radio‐telemetry studies or other sources.

Over the past two decades, there have been numerous calls to make ecology a more predictive science through direct empirical assessments of ecological models and predictions. While the widespread use of model selection using information criteria has pushed ecology toward placing a higher emphasis on prediction, few attempts have been made to validate the ability of information criteria to correctly identify the most parsimonious model with the greatest predictive accuracy. Here, we used an ecological forecasting framework to test the ability of information criteria to accurately predict the relative contribution of density dependence and density-independent factors (forage availability, harvest, weather, wolf [Canis lupus] density) on inter-annual fluctuations in beaver (Castor canadensis) colony densities. We modeled changes in colony densities using a discrete-time Gompertz model, and assessed the performance of four models using information criteria values: density-independent models with (1) and without (2) environmental covariates; and density-dependent models with (3) and without (4) environmental covariates. We then evaluated the forecasting accuracy of each model by withholding the final one-third of observations from each population and compared observed vs. predicted densities. Information criteria and our forecasting accuracy metrics both provided strong evidence of compensatory density dependence in the annual dynamics of beaver colony densities. However, despite strong within-sample performance by the most complex model (density-dependent with covariates) as determined using information criteria, hindcasts of colony densities revealed that the much simpler density-dependent model without covariates performed nearly as well predicting out-of-sample colony densities. The hindcast results indicated that the complex model over-fit our data, suggesting that parameters identified by information criteria as important predictor variables are only marginally valuable for predicting landscape-scale beaver colony dynamics. Our study demonstrates the importance of evaluating ecological models and predictions with long-term data and revealed how a known limitation of information criteria (over-fitting of complex models) can affect our interpretation of ecological dynamics. While incorporating knowledge of the factors that influence animal population dynamics can improve population forecasts, we suggest that comparing forecast performance metrics can likewise improve our knowledge of the factors driving population dynamics.

Statistical population reconstruction using age-at-harvest and catch-effort data has recently emerged as a robust and versatile approach to estimating the demographic dynamics of harvested populations of wildlife. Although there are clear benefits to incorporating radio-telemetry data into reconstruction efforts, these data are costly and time-consuming to collect. Managers that consider collecting these data alongside existing efforts could benefit from a comprehensive examination of how such benefits are influenced by the amount of radio-telemetry data collected. Using a harvested population of American marten (Martes americana) in northeastern Minnesota, USA as a case study, we investigated the performance of population reconstruction using information on natural, harvest, or combined mortality derived from radio-telemetry data collected over different numbers of years and with different numbers of animals collared each year. We simulated populations under a range of conditions and determined that incorporating radio-telemetry data on natural and harvest mortality significantly improved model precision, and that each additional animal collared per year yielded a 0.50 ± 0.14% (SE) improvement in precision, whereas every additional year of radio-telemetry data resulted in a 2.42 ± 0.70% improvement. Thus, including another year of radio-telemetry resulted in similar gains in precision as including approximately 5 additional animals collared per year. In our applied marten example, incorporating radio-telemetry data resulted in a significantly higher estimate of trapping vulnerability (0.20 vs. 0.058) and an overall smaller population size than reconstruction based solely on age-at-harvest and trapper effort data. These results illustrate the benefits of performing auxiliary studies, caution against relying on the results of population reconstruction based solely on age-at-harvest and hunter-effort data, and demonstrate that improvements from incorporating radio-telemetry data become evident even after as few as 2 years of data collection.

The genetic effects of harvest may be especially important in species that form social groups, such as gray wolves ( Canis lupus ). Though much research exists on the ecology and population dynamics of gray wolves, little research has focused on how anthropogenic harvest relates to the genetics of wolf populations. To analyze the short-term genetic consequences of the first two years of public wolf harvest in Minnesota following delisting under the Endangered Species Act, we genotyped harvested individuals at 18 microsatellite loci and quantified changes in population genetic structure and diversity in the first post-harvest year. If the harvest rate was high enough to create detectable genetic changes, population structure and differentiation between clusters could both increase because of decreased natal dispersal and increased disperser mortality, or they could decrease because of increased immigration from outside the population. In the Minnesota population, heterozygosity and allelic richness were not significantly different between years. However, population genetic structure increased and effective migration decreased among the sampled wolves. While the role of anthropogenic harvest in these changes cannot be distinguished from other confounding factors, this analysis suggests that harvest has a non-negligible effect and indicates the need for continued study to determine whether harvest-induced changes in genetic structure affect the evolutionary trajectory of harvested populations.

Humans have used wild furbearers for various purposes for thousands of years. Today, furbearers are sustainably used by the public for their pelts, leather, bones, glands, meat, or other purposes. In North America, contemporary harvest of furbearers has evolved along with trap technologies and societal concerns, and is now highly regulated and more closely coupled with harvest analysis and population monitoring. Traps and regulated trapping programs provide personal or cultural rewards that can also support conservation, and can assist with advancing ecological knowledge through research, protecting endangered species, restoring populations or habitats, protecting personal property, and enhancing public health and safety. However, animal welfare and trap selectivity remain important topics for furbearer management in North America, as they have for more than a century. A related international challenge to modern furbearer management came with the Wild Fur Regulation by the European Union, which passed in 1991. This regulation prohibited use of foothold traps in many European countries and the importation of furs and manufactured fur products to Europe from countries that allowed use of foothold traps or trapping methods that did not meet internationally agreed-upon humane trapping standards. To address existing national concerns and requirements of the Wild Fur Regulation, the United States and European Union signed a non-binding bilateral understanding that included a commitment by the United States to evaluate trap performance and advance the use of improved traps through development of best management practices (BMPs) for trapping. Our testing followed internationally accepted restraining-trap standards for quantifying injuries and capture efficiency, and we established BMP pass-fail thresholds for these metrics. We also quantified furbearer selectivity, and qualitatively assessed practicality and user safety for each trap, yielding overall species-specific performance profiles for individual trap models. We present performance data for 84 models of restraining traps (6 cage traps, 68 foothold traps, 9 foot-encapsulating traps, and 1 power-activated footsnare) on 19 furbearing species, or 231 trap-species combinations. We conducted post-mortem examinations on 8,566 furbearers captured by trappers. Of the 231 trap model-species combinations tested, we had sufficient data to evaluate 173 combinations, of which about 59% met all BMP criteria. Pooling species, cage traps produced the lowest average injury score (common injuries included tooth breakage), with minimal differences across other trap types; species-specific patterns were generally similar, with the exception of raccoons (Procyon lotor) for which foot-encapsulating traps performed better than other foot-restraining trap types. Padded-jaw foothold traps performed better than standard-jaw models for many species, though often similar to and occasionally worse than offset- or laminated-jaw models. Most traps we tested had high capture efficiency; only 5 (3%) failed BMP standards strictly because of poor efficiency. Average furbearer selectivity was high across all trap types we evaluated and was lowest for footsnares (88%) and highest for foot-encapsulating traps (99%). Mortality from trap-related injury in restraining traps we tested was very rare for furbearers (0.5% of animals). In over 230,000 trap-nights across a 21-year period, no individuals of a threatened or endangered species were captured. Of 9,589 total captures, 11% were non-furbearers, of which 83% were alive upon trap inspection; nearly all non-furbearer mortalities were birds, rabbits, or squirrels. Approximately 2% of total captures were feral or free-ranging dogs (Canis familiaris), of which none died or were deemed in need of veterinary care by either our technicians or the owners (if located). Similarly, 3% of total captures were feral or free-ranging cats (Felis catus); 2 were dead, and although locating potential owners was often impossible, none of the remaining cats were deemed in need of veterinary care by technicians or owners. Our results show that furbearer selectivity was high for all trap types evaluated, mortality or significant injury was very rare for domestic (or feral) animals, and the most potential for mortality or injury of non-furbearers was with smaller animals, a majority of which were squirrels and rabbits. Our results suggest that injury scores for a given trap-species combination are unlikely to vary significantly across states or regions of the United States, provided similar methods are employed. Our data also suggest that taxonomic affiliation and body-size groupings are correlated with injury scores, presumably through morphological, physiological, or behavioral adaptations or responses that influence injury potential during restraint; higher injury scores in foot-restraining trap types were more likely in smaller or more dexterous species, whereas injury scores were typically lowest for the felids we evaluated. For some species (e.g., American badger [Taxidea taxus], bobcat [Lynx rufus]), most restraining traps we tested met BMP standards, whereas few restraining traps we tested met standards for other species (e.g., muskrat [Ondatra zibethicus], striped skunk [Mephitis mephitis]). Comparison of our results with survey information collected during 2015 on trap use in the United States indicates that approximately 75% of all target furbearers harvested were taken in BMP-compliant traps, with another 10% taken in traps yet to be tested on that species. Future trap testing and development should focus on commonly used traps not yet tested on a species, species for which few passing traps currently pass BMP criteria, and trap models and modifications most likely to minimize trap injuries given a species morphology, physiology, and behavior. Outreach efforts should focus on general BMP awareness, discouraging use of traps that fail BMP standards for a given species, and public outreach on trapping. Restraining (and other) traps have evolved substantially in recent decades and offer numerous benefits to individuals, conservation, and society. However, continuing to address societal concerns remains a critical component of modern regulated trapping and furbearer management. Published trapping BMPs are regularly updated online and may include additional approved restraining and killing traps that were evaluated as part of testing by Canada. We will periodically update the trap performance tables and figures we presented and make them available online at the Association of Fish and Wildlife Agencies website. Published 2020. This article is a U.S. Government work and is in the public domain in the USA. Wildlife Monographs published by Wiley Periodicals LLC on behalf of The Wildlife Society. Los seres humanos han utilizado a los animales silvestres de peletería para diversos fines durante miles de años. Hoy en día, el público utiliza de manera sostenible los animales de peletería para pieles, cueros, huesos, glándulas, carne u otros fines. En América del Norte, la cosecha contemporánea de animales de peletería, ha evolucionado junto con las tecnologías de trampas y las preocupaciones sociales, y ahora está altamente regulada y más estrechamente relacionada con el análisis de la cosecha y el monitoreo de la población. Las trampas y los programas de captura regulada brindan recompensas personales o culturales que también pueden apoyar la conservación y pueden ayudar a promover el conocimiento ecológico a través de la investigación, la protección de especies en peligro de extinción, la restauración de poblaciones o hábitats, la protección de la propiedad personal y la mejora de la salud y la seguridad públicas. Sin embargo, el bienestar animal y la selectividad de las trampas siguen siendo temas importantes para el manejo de los animales de peletería en América del Norte, como lo han sido durante más de un siglo. Un desafío internacional relacionado con la gestión moderna de los animales de peletería llegó con el Reglamento de Pieles Silvestres de la Unión Europea, que se aprobó en 1991. Este reglamento prohibía el uso de trampas que sujetan las patas (más específicamente pie y metatarso o metacarpo) de los animales en muchos países europeos y la importación de pieles y productos de piel manufacturados a Europa desde países que permitían uso de trampas que sujetan las patas o métodos de captura que no cumplieron con los estándares de captura humanitaria acordados internacionalmente. Para abordar las preocupaciones y los requisitos nacionales existentes del Reglamento Sobre Pieles Silvestres, los Estados Unidos y la Unión Europea firmaron un acuerdo bilateral, no vinculante, que incluía un compromiso de los Estados Unidos para evaluar el desempeño de las trampas y promover el uso de trampas mejoradas mediante el desarrollo de mejores prácticas de manejo (MPM) para la captura. Nuestras pruebas siguieron los estándares aceptados internacionalmente de trampas para sujetar patas (o también llamadas de restricción o contención) para cuantificar las lesiones y la eficiencia de captura, y establecimos umbrales de MPM de aceptable y no aceptable para estos parámetros. También cuantificamos la selectividad sobre los animales de peletería y evaluamos cualitativamente la practicidad y la seguridad del usuario para cada trampa, lo que arrojó perfiles generales de rendimiento sobre especies específicas para modelos de trampa individuales. Presentamos datos de rendimiento para 84 modelos de trampas de contención (6 trampas de jaula, 68 trampas para sujetar patas, 9 trampas de encapsulación de patas y 1 lazada de pata activada mecánicamente) en 19 especies de peletería, o 231 combinaciones de trampas y especies. Realizamos exámenes post mortem en 8,566 animales de peletería capturados por tramperos. De las 231 combinaciones de modelos de trampas y especies probadas, tuvimos datos suf

Wolves (Canis lupus) have been captured with foothold traps for several decades to equip them with radiocollars for population monitoring. However, trapping in most areas is limited to spring, summer, and autumn as cold winter temperatures can lead to frozen appendages in trapped animals. In addition, conflicts arise when domestic dogs encounter these traps in nonwinter seasons. An alternative capture method is the use of cable restraint devices (modified neck snares) in the winter. We evaluated injury scores, movement patterns, and space use of wolves captured in cable restraint devices and foothold traps in north-central Minnesota, USA, during 2012–2016. Injury scores did not differ between capture techniques; however, movement patterns and space use were different. We found that the movement away from the capture site appeared to plateau by approximately 8–10 days for wolves captured by either foothold traps or cable restraints, but wolves captured in traps travelled farther away. Daily movement rates reached an asymptote approximately 14 days earlier for wolves captured with cable restraints as compared with wolves caught with foothold traps. We found the space use among wolves caught with cable restraint devices plateaued in a shorter time frame than wolves caught with foothold traps whether using days since capture (38 days earlier) or number of locations (149 locations earlier). When we controlled for seasonal effects and the presence of a capture using locational data collected 6 months later, there was no difference in space use. We concluded that wolves captured in cable restraints recovered more quickly from the capture and resumed space use and activity patterns more rapidly than wolves captured with foothold traps.

The river otter (Lontra canadensis) has a complex social system, which varies widely across its range. We examined patterns of space use and social interactions for a native population of river otters in southeastern Minnesota. We radiomarked 28 river otters and monitored annual home ranges and core areas, static and dynamic interactions, and site fidelity. We compared these characteristics and interactions between sexes and age classes. Annual home ranges of male river otters were 3.2 times greater than those of females (P = 0.042), and annual core areas of males were 2.9 times greater than those of females (P = 0.083). The static interactions among river otters were extensive, with 69% of the individuals exhibiting core-area overlap. Overall dynamic interactions were positive (i.e., animals were closer together than expected). Males used 74% of their year 1 home range during year 2, and females used 75%. Females on average used only 39% of their core area from year 1 during year 2, whereas males used 65%. In general, conspecifics were not excluded from home ranges or core areas and signs of cooperation were evident, suggesting that river otters in southeastern Minnesota were social rather than territorial.

An understanding of activity patterns of wildlife in relation to abiotic and biotic factors enables biologists to better understand the ecology of species, manage resources, standardize survey methods, and serve as an index of the relative density of a species. River otters (Lontra canadensis) were radiotracked between June 2002 and October 2003. Using radiotracking data, we conducted exploratory analyses to determine relative influence of abiotic and biotic factors on 2 measures of activity of otters. Abiotic factors included air temperature, barometric pressure, lunar phase, biological season, and time of day; the biotic factor was sex. Activity was measured indirectly via movement rates and directly as the proportion of location attempts recorded as active (PLA). Movement rate was defined as the distance traveled by an otter between consecutive location estimates. Generalized linear mixed models were used to explore the influence of covariates on both measures of otter activity. The model best explaining variation in movement rate included biological season, sex, a season*sex interaction, and time of day. Males moved at greater rates than females during breeding and winter seasons but moved at similar rates to females during summer. Covariates found to account for most variation in the PLA of otters included time of day, season, and temperature. Otters were active throughout the day but with bimodal peaks in the PLA during late evening and early morning hours. The PLA of otters was highest during breeding season, lowest during winter, and intermediate in summer months. In addition, the PLA of otters decreased slightly with increasing temperature. Overall, the PLA of otters in our study area was influenced by abiotic factors, and movement rates of otters were influenced by abiotic and biotic factors.