In the western United States, wolverines (Gulo gulo) typically occupy high-elevation habitats. Because wolverine populations occur in vast, remote areas across multiple states, biologists have an ...imperfect understanding of this species’ current distribution and population status. The historical extirpation of the wolverine, a subsequent period of recovery, and the lack of a coordinated monitoring program in the western United States to determine their current distribution further complicate understanding of their population status. We sought to define the limits to the current distribution, identify potential gaps in distribution, and provide a baseline dataset for future monitoring and analysis of factors contributing to changes in distribution of wolverines across 4 western states. We used remotely triggered camera stations and hair snares to detect wolverines across randomly selected 15-km × 15-km cells in Idaho, Montana, Washington, and Wyoming, USA, during winters 2016 and 2017. We used spatial occupancy models to examine patterns in wolverine distribution. We also examined the influence of proportion of the cell containing predicted wolverine habitat, human-modified land, and green vegetation, and area of the cluster of contiguous sampling cells. We sampled 183 (28.9%) of 633 cells that comprised a suspected wolverine range in these 4 states and we detected wolverines in 59 (32.2%) of these 183 sampled cells. We estimated that 268 cells (42.3%; 95% CI=182–347) of the 633 cells were used by wolverines. Proportion of the cell containing modeled wolverine habitat was weakly positively correlated with wolverine occupancy, but no other covariates examined were correlated with wolverine occupancy. Occupancy rates (ψ) were highest in the Northern Continental Divide Ecosystem (ψ range=0.8–1), intermediate in the Cascades and Central Mountains of Idaho (ψ range=0.4–0.6), and lower in the Greater Yellowstone Ecosystem (ψ range=0.1–0.3). We provide baseline data for future surveys of wolverine along with a design and protocol to conduct those surveys.
Big-game hunting is a valuable resource for outdoor recreation opportunities, an economic driver for state and local economies, and the primary mechanism for funding game and non-game wildlife ...management. However, hunting license sales are declining, leading many state wildlife management agencies to re-evaluate funding and management structures. Understanding the mechanisms behind such declines, and diagnosing the persistence of such trends is necessary to anticipate license fund fluctuations. To examine hunter recruitment and retention rates, we analyzed a data set of >490,000 deer and elk license records from 2002 to 2011 from the Montana Fish, Wildlife and Parks' Automated Licensing System. We used a temporal symmetry model in a mark-recapture framework to estimate hunter retention, recruitment rates, and population change, and then used population change estimates to forecast future hunter populations. We used covariates of gender, age, residency, and license price to improve model parsimony. Millennial generation hunters increased during the 11-year analysis, and this was driven by high recruitment rates of young hunters, especially women, but recruitment decreased dramatically as youth aged. Because Baby Boomers constitute such a large proportion of the hunting population, decreases in recruitment and retention in this cohort drove declines in the Montana hunter population. Increasing license price decreased the probability of recruiting and retaining hunters. The hunter population was stable until 2006, but has been declining since that time with nearly a 50% decline in hunter recruitment from 2002 to 2011.
Monitoring rare and elusive carnivores is inherently challenging because they often occur at low densities and require more resources to effectively assess status and trend. The fisher (Pekania ...pennanti) is an elusive mesocarnivore endemic to North America; in its western populations it is classified as a species of greatest conservation need. During winter of 2018–2019, we deployed remotely triggered cameras in randomly selected, spatially balanced 7.5‐km × 7.5‐km grid cells across a broad study area in western Montana, Idaho, and eastern Washington, USA. As part of this large‐scale, multi‐state monitoring effort, we conducted an occupancy assessment of the Northern Rocky Mountain fisher population at a range‐wide scale. We used non‐spatial occupancy models to determine the current extent of fisher occurrence in the Northern Rocky Mountains and to provide baseline occupancy estimates across a broad study area and a refined sampling frame for future monitoring. We used a spatial occupancy model to determine patterns in fisher occurrence across their Northern Rocky Mountain range while explicitly correcting for spatially induced overdispersion. Additionally, we assessed factors that influenced fisher occurrence through covariate occupancy modeling that considered predicted fisher habitat, site‐level environmental characteristics, and the influence of available harvest records (incidental and regulated). We detected fishers in 32 out of 318 (10%) of our surveyed cells, and estimated that overall, 160 (14%; 95% CI = 115–218) of 1,143 grid cells were occupied by fishers. Fisher occupancy was positively associated with our stratum that contained cells with a greater proportion of predicted fisher habitat and with proximity to nearest 2000–2015 harvest location. Fisher occupancy was weakly and positively associated with increased canopy cover. Our spatial model identified 2 areas with higher predicted occupancy: a large area across the Idaho Nez Perce‐Clearwater National Forest, and a smaller area in the Cabinet Mountain Range crossing the northern border of Idaho and Montana. We used spatial occupancy results from our original sampling frame to create a biologically derived refined sampling frame for future monitoring. Within the bounds of our refined sampling frame, we estimated that 155 (22%; 95% CI = 110–209) of 700 grid cells were occupied by fishers. By incorporating our increasing understanding of fisher habitat with contemporary analytical techniques, we defined current range‐wide occupancy of the Northern Rocky Mountain fisher population, identified core areas of fisher occurrence for future conservation efforts, and used our model results to create a refined sampling frame for future fisher monitoring in the Northern Rocky Mountains.
We provide occupancy and detection probability data from the first multi‐state, range‐wide study of the Northern Rocky Mountain fisher population. We provide baseline data for comparison against future fisher surveys as well as a study design and protocol to conduct future surveys.
•We created a statewide metapopulation model for mountain lions in Montana.•We used our model to predict change in population growth given proposed harvest rates.•The effect of uncertainty in initial ...parameter estimations and dispersal rate lessen with scale.•Tools such as this are useful in harvest planning at regional and statewide levels.
To be most effective, the scale of wildlife management practices should match the range of a particular species’ movements. For this reason, combined with our inability to rigorously or regularly census mountain lion populations, several authors have suggested that mountain lions be managed in a source-sink or metapopulation framework. We used a combination of resource selection functions, mortality estimation, and dispersal modeling to estimate cougar population levels in Montana statewide and potential population level effects of planned harvest levels. Between 1980 and 2012, 236 independent mountain lions were collared and monitored for research in Montana. From these data we used 18,695 GPS locations collected during winter from 85 animals to develop a resource selection function (RSF), and 11,726 VHF and GPS locations from 142 animals along with the locations of 6343 mountain lions harvested from 1988–2011 to validate the RSF model. Our RSF model validated well in all portions of the State, although it appeared to perform better in Montana Fish, Wildlife and Parks (MFWP) Regions 1, 2, 4 and 6, than in Regions 3, 5, and 7. Our mean RSF based population estimate for the total population (kittens, juveniles, and adults) of mountain lions in Montana in 2005 was 3926, with almost 25% of the entire population in MFWP Region 1. Estimates based on a high and low reference population estimates produce a possible range of 2784 to 5156 mountain lions statewide. Based on a range of possible survival rates we estimated the mountain lion population in Montana to be stable to slightly increasing between 2005 and 2010 with lambda ranging from 0.999 (SD=0.05) to 1.02 (SD=0.03). We believe these population growth rates to be a conservative estimate of true population growth. Our model suggests that proposed changes to female harvest quotas for 2013–2015 will result in an annual statewide population decline of 3% and shows that, due to reduced dispersal, changes to harvest in one management unit may affect population growth in neighboring units where smaller or even no changes were made. Uncertainty regarding dispersal levels and initial population density may have a significant effect on predictions at a management unit scale (i.e. 2000km2), while at a regional scale (i.e. 50,000km2) large differences in initial population density result in relatively small changes in population growth rate, and uncertainty about dispersal may not be as influential. Doubling the presumed initial density from a low estimation of 2.19 total animals per 100km2 resulted in a difference in annual population growth rate of only 2.6% statewide when compared to high density of 4.04 total animals per 100km2 (low initial population estimate λ=0.99, while high initial population estimate λ=1.03). We suggest modeling tools such as this may be useful in harvest planning at a regional and statewide level.
The western United States offers a case study on the importance of access to large population centers and their markets, via road and air travel, for economic development. The vast distances between ...towns and cities in the American West can be a detriment to business, yet they also serve to attract technology and knowledge-based workers seeking to live in a picturesque setting. In spite of the increasing importance of amenities to migration and business location, also needed is access to markets, particularly via commercial air service. We test a new county classification system for the western United States to reflect differing degrees of access to population centers and account for the increasing importance of airports. Past classifications are based on population size and cross-county commuting. We examine the validity of this new classification and test for differences in economic performance among the three county types. Our findings show that there are three distinct Wests that can be classified using economic performance measures and socioeconomic characteristics. The results show that “metro” and “isolated” counties are clearly distinct, but “connected” counties, those that are rural in nature but have ready access to metropolitan areas via air travel, can be difficult to distinguish from “metro” and “isolated” counties. Much of the variation is explained by travel distance to airports. The findings illustrate the importance of airports in rural development, and the limitations facing those communities that are isolated from markets and population centers. The results apply to other parts of the world with similar characteristics that include large expanses of open space, natural amenities that attract migrants and stimulate new business, and different degrees of access to large population centers via road or air travel, and therefore different rates of economic growth.
Although most wildlife professionals agree that science should inform wildlife management decisions, disconnect still exists between researchers and managers. If researchers are not striving to ...incorporate their findings into management decisions, support for research programs by managers can wane. If managers are not using research findings to inform management decisions, those decisions may be less effective or more vulnerable to legal challenges. Both of these situations can have negative consequences for wildlife conservation. We outline a collaborative research-management approach to bridging the gap between wildlife managers and researchers. We describe differences in perspectives, perceptions, and priorities between managers and researchers; outline how and why the divide between researchers and managers has likely occurred and continues to grow; and present specific strategies and recommendations to foster stronger collaborations between managers and researchers. We advocate increased synergy between managers and researchers based on a shared vision of conservation and a collaborative structure that rewards researchers and managers. Most importantly, we suggest that relationships and communication between managers and researchers must be established early in research development and decision-making processes, fostering the trust needed for collaboration. Institutions and agencies can facilitate these relationships by creating opportunities and incentives for integrating collaborative research into management decisions. We suggest this approach will strengthen ties between researchers and managers, increase relevance of research to management decisions, promote effectiveness of management decisions, reduce legal challenges, and ultimately produce positive, tangible, and lasting effects on wildlife conservation.
Wildlife reservoirs of infectious disease are a major source of human-wildlife conflict because of the risk of potential spillover associated with commingling of wildlife and livestock. In the ...Greater Yellowstone Ecosystem, the presence of brucellosis (Brucella abortus) in free-ranging elk (Cervus canadensis) populations is of significant management concern because of the risk of disease transmission from elk to livestock. We identified how spillover risk changes through space and time by developing resource selection functions using telemetry data from 223 female elk to predict the relative probability of female elk occurrence daily during the transmission risk period. We combined these spatiotemporal predictions with elk seroprevalence, demography, and transmission timing data to identify when and where abortions (the primary transmission route of brucellosis) were most likely to occur. Additionally, we integrated our predictions of transmission risk with spatiotemporal data on areas of potential livestock use to estimate the daily risk to livestock. We predicted that approximately half of the transmission risk occurred on areas where livestock may be present (i.e., private property or grazing allotments). Of the transmission risk that occurred in livestock areas, 98% of it was on private ranchlands as opposed to state or federal grazing allotments. Disease prevalence, transmission timing, host abundance, and host distribution were all important factors in determining the potential for spillover risk. Our fine-resolution (250-m spatial, 1-day temporal), large-scale (17,732 km²) predictions of potential elk-to-livestock transmission risk provide wildlife and livestock managers with a useful tool to identify higher risk areas in space and time and proactively focus actions in these areas to separate elk and livestock to reduce spillover risk.
Mountain lions (Puma concolor) are widely hunted for recreation, population control, and to reduce conflict with humans, but much is still unknown regarding the effects of harvest on mountain lion ...population dynamics. Whether human hunting mortality on mountain lions is additive or compensatory is debated. Our primary objective was to investigate population effects of harvest on mountain lions. We addressed this objective with a management experiment of 3 years of intensive harvest followed by a 6-year recovery period. In December 2000, after 3 years of hunting, approximately 66% of a single game management unit within the Blackfoot River watershed in Montana was closed to lion hunting, effectively creating a refuge representing approximately 12% (915 km²) of the total study area (7,908 km²). Hunting continued in the remainder of the study area, but harvest levels declined from approximately 9/1,000 km² in 2001 to 2/1,000 km² in 2006 as a result of the protected area and reduced quotas outside. We radiocollared 117 mountain lions from 1998 to 2006. We recorded known fates for 63 animals, and right-censored the remainder. Although hunting directly reduced survival, parameters such as litter size, birth interval, maternity, age at dispersal, and age of first reproduction were not significantly affected. Sensitivity analysis showed that female survival and maternity were most influential on population growth. Life-stage simulation analysis (LSA) demonstrated the effect of hunting on the population dynamics of mountain lions. In our non-hunted population, reproduction (kitten survival and maternity) accounted for approximately 62% of the variation in growth rate, whereas adult female survival accounted for 30%. Hunting reversed this, increasing the reliance of population growth on adult female survival (45% of the variation in population growth), and away from reproduction (12%). Our research showed that harvest at the levels implemented in this study did not affect population productivity (i.e., maternity), but had an additive effect on mountain lion mortality, and therefore population growth. Through harvest, wildlife managers have the ability to control mountain lion populations.
Wolf (Canis lupus) depredations of livestock are a ubiquitous source of conflict in every country where wolves and livestock overlap. We studied the spatial and temporal variation of wolf ...depredations of livestock in Montana during 2005–2015, including evaluations of targeted control efforts and public harvest as potential means to reduce depredations. During this time we collected spatial data for all confirmed wolf-livestock depredations, tallied the annual number of depredation events within hunting districts, and collected data for variables potentially predictive of depredation events. We decomposed variation in depredation data into 2 distinct components: the binary presence or absence of depredation events in each district-year, and the count of depredation events in district-years with ≥1 event. We found that presence-absence of depredations increased with wolf presence and wolf density, increased with livestock density, were highest at intermediate proportionate areas of agricultural land, and were a recurrent phenomenon such that districts with depredations the previous year were more likely to continue having them. Targeted removal, but not public harvest, significantly reduced the recurrent presence of depredations. The number of conflicts in district-years with ≥1 depredation event was positively correlated with wolf density, cattle density, intermediate proportionate areas of forested land, and the number of events during the previous year. Public harvest reduced the counts of depredation events in areas where conflict reoccurred, though with a modest predicted effect size of 0.22 fewer depredations/district-year, or 5.7 fewer depredation events statewide/year (8% of the annual average). Minimizing livestock losses is a top priority for wolf management. These results shed light on the broad-scale patterns behind chronic problems and the effectiveness of wolf management practices in addressing them.
Integrated Carnivore-Ungulate Management PROFFITT, KELLY M.; GARROTT, ROBERT; GUDE, JUSTIN A. ...
Wildlife monographs,
11/2020, Letnik:
206, Številka:
1
Journal Article
Recenzirano
Understanding the effectiveness of harvest regulations to manipulate population abundances is a priority for wildlife managers, and reliable methods are needed to monitor populations. This is ...particularly true in controversial situations such as integrated carnivore-ungulate management. We used an observational before-after-control-treatment approach to evaluate a case study in west-central Montana, USA, that applied conservative ungulate harvest together with liberalized carnivore harvest to achieve short-term decreases in carnivore abundance and increases in ungulate recruitment. Our study areas included the Bitterroot treatment area and the Clark Fork control area, where mountain lion populations (Felis concolor) were managed for a 30% reduction and for stability, respectively. The goals of the mountain lion harvest were to provide a short-term reduction of mountain lion predation on elk (Cervus canadensis) calves and an increase in elk recruitment, elk population growth rate, and ultimately elk abundance. We estimated mountain lion population abundance in the Bitterroot treatment and Clark Fork control areas before and 4 years after implementation of the 2012 harvest treatment. We developed a multi-strata spatial capture-recapture model that integrated recapture and telemetry data to evaluate mountain lion population responses to harvest changes. Mountain lion abundance declined with increasing harvest in the Bitterroot treatment area from 161 (90% credible interval CrI = 104, 233) to 115 (CrI = 69, 173). The proportion of males changed from 0.50 (CrI = 0.33, 0.67) to 0.28 (CrI = 0.17, 0.40), which translated into a decline in the abundance of males, and similar abundances of females (before: males = 80 CrI = 52, 116, females = 81 CrI = 52, 117; after: males = 33 CrI = 20, 49, females = 82 CrI = 49, 124). In the Clark Fork control area, an area twice as large as the Bitterroot treatment area, we found no evidence of changes in overall abundance or proportion of males in the population. The proportion of males changed from 0.42 (CrI = 0.26, 0.58) to 0.39 (CrI = 0.25, 0.54), which translated into similar abundances of males and females (before: males = 24 CrI = 16, 36, females = 33 CrI = 21, 39; after: males = 28 CrI = 18, 41, females = 44 CrI = 29, 64). To evaluate if elk recruitment and population growth rate increased following treatment, we developed an integrated elk population model. We compared recruitment and population growth rate during the 5 years prior to and 5 years following implementation of the mountain lion harvest treatment for 2 elk populations within the Bitterroot treatment area and 2 elk populations within the Clark Fork control area. We found strong evidence that temporal trends differed between the 2 areas. In the Bitterroot treatment area, per capita elk recruitment was stable around an estimated median value of 0.23 (CrI = 0.17, 0.36) in the pre-treatment period (2007–2011), increased immediately after treatment (2013) to 0.42 (CrI = 0.29, 0.56), and then declined to 0.21 (CrI = 0.11, 0.32) in 2017. In contrast, per capita elk recruitment estimates in the Clark Fork control area had similar median values during the pre- (2007–2011: 0.30, CrI = 0.2, 0.35) and post-treatment periods (2013–2017: 0.31, CrI = 0.26, 0.36). These changes in recruitment corresponded to similar changes in elk population growth rate, although population growth rates were also subject to variation due to changing elk harvest. In the Bitterroot treatment area, population growth rates in the pre-treatment period were stable to slightly declining, with an estimated median value of 0.92 (CrI = 0.88, 1.07) in the pre-treatment period (2007–2011). Population growth rate during the post-treatment period increased immediately after treatment (2012: 1.17, CrI = 1.14, 1.20) prior to declining to 1.06 (CrI = 1.04, 1.09) in 2016. In contrast, the median population growth rates were roughly equal in the Clark Fork control area during the pre-treatment period (1.01, CrI = 0.86, 1.09) from 2007 to 2011 and post-treatment period (1.00, CrI = 0.83, 1.15) from 2013 to 2017. Together, these results indicate that the harvest treatment achieved a moderate (i.e., 29%) reduction in mountain lion population abundance within the treatment area that corresponded with short-term increases in elk recruitment and population growth. Elk population demographic responses suggest that the harvest treatment effect was strongest immediately after the mountain lion harvest treatment was implemented and lessened over time as the harvest treatment was reduced. This suggests that the short-term harvest treatment resulted in short-term demographic responses in elk populations, and more sustained harvest treatments would be necessary to achieve longer-term elk population demographic responses. We recommend that wildlife managers seeking to balance carnivore and ungulate population objectives design rigorous carnivore and ungulate population monitoring programs to assess the effects of harvest management programs. Assessing and understanding effects of carnivore harvest management programs will help to set realistic expectations regarding the effects of management programs on carnivore and ungulate populations and allow managers to better design programs to meet desired carnivore and ungulate population objectives.
Comprendre l’efficacité des règlements de récolte à contrôler l’abondance des populations est une priorité pour les gestionnaires de la faune, et des méthodes fiables sont nécessaires pour suivre l’état des populations. Cela est particulièrement vrai face à des situations controversées telles que la gestion intégrée des carnivores et des cervidés. Nous avons utilisé une approche observationnelle avant-après-témoin-traitement dans le cadre d’une étude de cas prenant place dans le centre-ouest du Montana, aux États-Unis. L’étude impliquait une récolte de cervidés conservatrice et une récolte de carnivores plus permissive afin de réduire l’abondance des carnivores à court terme et d’augmenter le recrutement de cervidés. Nos aires d’étude comprenaient la zone expérimentale de la Bitterroot où la gestion visait à réduire les populations de couguars (Felis concolor) de 30%, ainsi que la zone témoin de Clark Fork où l’objectif était de maintenir des populations stables. La récolte de couguars visait la réduction à court terme de la prédation sur les faons de wapitis (Cervus canadensis), tout en augmentant le recrutement de wapitis, de même que le taux de croissance et l’abondance de leur population. Nous avons estimé l’abondance des couguars dans la zone de traitement de la Bitterroot et dans la zone témoin de Clark Fork avant la mise en oeuvre du traitement de récolte en 2012, puis 4 ans après. Nous avons développé un modèle spatial de capture-marquage-recapture pour population stratifée qui intégrait des données de recapture et de télémétrie afin d’évaluer comment la population de couguars réagit aux variations du taux de récolte. L’abondance de couguars a diminué avec l’augmentation de la récolte dans la zone de traitement de la Bitterroot, passant de 161 (intervalle de crédibilité à 90% ICr = 104, 233) à 115 (ICr = 69, 173). La proportion de mâles est alors passée de 0,50 (ICr = 0,33, 0,67) à 0,28 (ICr = 0,17, 0,40), ce qui reflète la diminution de l’abondance des mâles et le maintien de l’abondance des femelles (avant: mâles = 80 ICr = 52, 116, femelles = 81 ICr = 52, 117; après: mâles = 33 ICr = 20, 49, femelles = 82 ICr = 49, 124). Dans la zone témoin de Clark Fork, une zone deux fois plus grande que la zone de traitement de la Bitterroot, nous n’avons détecté aucun changement dans l’abondance des mâles ou dans leur proportion au sein de la population. La proportion de mâles est passée de 0,42 (ICr = 0,26, 0,58) à 0,39 (ICr = 0,25, 0,54), se traduisant par une abondance similaire entre les mâles et les femelles (avant: mâles = 24 ICr = 16, 36, femelles = 33 ICr = 21, 39; après: mâles = 28 ICr = 18, 41, femelles = 44 ICr = 29, 64). Pour évaluer si le recrutement de wapitis et le taux de croissance de leur population ont augmenté suite au traitement, nous avons développé un modèle intégré des populations de wapitis. Nous avons comparé le taux de recrutement et de croissance de 4 populations de wapitis au cours des 5 années qui ont précédé et des 5 qui ont suivi le début de la récolte de couguars. Deux populations de wapitis se situaient dans la zone de traitement de la Bitterroot et 2 dans la zone témoin de Clark Fork. Nos résultats suggèrent fortement que les variations temporelles des populations différaient entre les 2 aires d’étude. Dans la zone de traitement de la Bitterroot, le recrutement des wapitis par individu était stable autour d’une valeur médiane de 0,23 (ICr = 0,17, 0,36) durant la période de prétraitement (2007–2011), il a augmenté suite au traitement pour atteindre un niveau intermédiaire de 0,42 (ICr = 0,29, 0,56) en 2013, puis il a diminué à 0,21 (ICr = 0,11, 0,32) en 2017. En revanche, le recrutement des wapitis par individu avait des valeurs médianes similaires durant les périodes pré- (2007–2011: 0,30, ICr = 0,2, 0,35) et de post-traitement (2013–2017: 0,31, ICr = 0,26, 0,36) dans la zone témoin de Clark Fork. Les variations du recrutement étaient liées à des changements similaires dans le taux de croissance des populations de wapitis, bien que le taux de croissance des populations ait également varié suite aux variations de récolte de wapitis. Dans la zone de traitement de la Bitterroot, les taux de croissance des populations étaient stables ou légèrement en baisse durant la période de prétraitement (2007–2011), avec une valeur médiane de 0,92 (ICr = 0,88, 1,07). Le taux de croissance de la population a augmenté immédiatement après le traitement (2012: 1,17, ICr = 1,14, 1,20), avant de diminuer à 1,06 (ICr = 1,04, 1,09) en 2016. En revanche, le taux de croissance médian des populatio
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