Northwest Montana Research Articles

Psychological needs, self-efficacy, motivation, and resistance training outcomes in a 16-week barbell training program for adults.

Despite extensive research on the relationship between psychological factors and aerobic training, there remains a gap in understanding these relationships within resistance training (RT), particularly barbell-based RT. This study aimed to examine the associations between basic psychological needs, behavioral regulation, self-efficacy, and a longitudinal barbell-based RT program for adults. Forty-three adults (M age = 45.09 ± 10.72) were recruited from the Competitive Edge resistance training program at a medical fitness center in Northwest Montana. The study followed an 18-week schedule: 8 weeks of training, 1 week of active recovery, and 8 additional weeks of training. The results reveal several significant findings. First, the basic psychological need for competence significantly increased from baseline (M = 5.06) to post-program (M = 5.30), (p = 0.017). Second, the composite score of the BREQ-3 significantly predicting muscular strength improvements in the deadlift (β = 3.64, p = 0.039). Third, both mastery (p = 0.021) and resilience (p = 0.007) self-efficacy subscales increased from baseline to post-program. Fourth, exploratory analyses indicated that the reasons to exercise scale predicted increases in muscular endurance with the weight management (β = 10.016, p = 0.046) and solitude (β = 6.792, p = 0.037) subscales. These findings highlight the importance of psychological factors in predicting strength outcomes and muscular endurance, suggesting that psychological interventions may complement physical training to maximize benefits. This research contributes valuable insights into how psychological factors influence training outcomes, potentially guiding future interventions and program designs to better support strength development and endurance in resistance training contexts.

Evaluating density-weighted connectivity of black bears (Ursus americanus) in Glacier National Park with spatial capture–recapture models

BackgroundImproved understanding of wildlife population connectivity among protected area networks can support effective planning for the persistence of wildlife populations in the face of land use and climate change. Common approaches to estimating connectivity often rely on small samples of individuals without considering the spatial structure of populations, leading to limited understanding of how individual movement links to demography and population connectivity. Recently developed spatial capture-recapture (SCR) models provide a framework to formally connect inference about individual movement, connectivity, and population density, but few studies have applied this approach to empirical data to support connectivity planning.MethodsWe used mark-recapture data collected from 924 genetic detections of 598 American black bears (Ursus americanus) in 2004 with SCR ecological distance models to simultaneously estimate density, landscape resistance to movement, and population connectivity in Glacier National Park northwest Montana, USA. We estimated density and movement parameters separately for males and females and used model estimates to calculate predicted density-weighted connectivity surfaces.ResultsModel results indicated that landscape structure influences black bear density and space use in Glacier. The mean density estimate was 16.08 bears/100 km2 (95% CI 12.52–20.6) for females and 9.27 bears/100 km2 (95% CI 7.70–11.14) for males. Density increased with forest cover for both sexes. For male black bears, density decreased at higher grizzly bear (Ursus arctos) densities. Drainages, valley bottoms, and riparian vegetation decreased estimates of landscape resistance to movement for male and female bears. For males, forest cover also decreased estimated resistance to movement, but a transportation corridor bisecting the study area strongly increased resistance to movement presenting a barrier to connectivity.ConclusionsDensity-weighed connectivity surfaces highlighted areas important for population connectivity that were distinct from areas with high potential connectivity. For black bears in Glacier and surrounding landscapes, consideration of both vegetation and valley topography could inform the placement of underpasses along the transportation corridor in areas characterized by both high population density and potential connectivity. Our study demonstrates that the SCR ecological distance model can provide biologically realistic, spatially explicit predictions to support movement connectivity planning across large landscapes.

Assessing Complexity and Stakeholder and Rightsholder Trust in Outdoor Recreation Management on the Pacific Northwest National Scenic Trail

The Pacific Northwest National Scenic Trail (PNT) traverses 1,200 miles from the Continental Divide to the Pacific Ocean. The portion of the trail in Northwest Montana and the Idaho Panhandle is at the nexus of a complex conflict situation involving outdoor recreation, wildlife conservation, and social-cultural values. This evolving conflict has gained national attention due to the diverse stakeholder interests and litigation against the US Forest Service, who administers the trail. The tension among the stakeholder groups and the various ecological and social-cultural dimensions at play illuminate the complexity of managing long-distance trails. Administrators of long-distance trails must evaluate and mitigate social, ecological, and cultural risks. This research note explores complexity and trust ecology among key PNT stakeholders, and discusses opportunities for incorporating trust research in transboundary recreation planning and research.

Modeling the distribution of headwater streams using topoclimatic indices, remote sensing and machine learning.

Headwater streams (HWS) are ecologically important components of montane ecosystems. However, they are difficult to map and may not be accurately represented in existing spatial datasets. We used topographically resolved climatic water balance data and satellite indices retrieved from Google Earth Engine to model the occurrence (presence or absence) of HWS across Northwest Montana. A multi-scale feature selection (MSFS) procedure and boosted regression tree models/machine learning algorithms were used to identify variables associated with HWS occurrence. In final model evaluation, models that included climatic water balance deficit were more accurate (83.5% ranging from 82.9% to 83.7%) than using only terrain indices (81.1% ranging from 80.7% to 81.4%) and improved upon estimates of stream extent represented by the National Hydrography Dataset Plus High Resolution (NHDPlus HR) (82.7% ranging from 82.5% to 83.1%). Including topoclimate captured the varying effect of upslope accumulated area across a strong moisture gradient. Multi-scale cross-validation, coupled with a MSFS algorithm allowed us to find a parsimonious model that was not immediately evident using standard cross-validation procedures. More accurate spatial model predictions of HWS have potential for immediate application in land and water resource management, where significant field time can be spent identifying potential stream impacts prior to contracting and planning.

Prevalence and Mortality of Moose (Alces alces) Infected with Elaeophora schneideri in Montana, USA.

Elaeophora schneideri is a filarial nematode of North America that occasionally infects aberrant ruminant hosts such as moose (Alces alces). The role E. schneideri plays in clinical morbidity or mortality of moose remains uncertain. We sampled predominantly hunter-killed adult moose (n=127) to characterize the spatial patterns of prevalence and intensity of worms in carotid arteries of moose in Montana. We compared prevalence and intensity of E. schneideri within these moose to a separate sample of adult moose that died of health-related causes (n=34). We found lower prevalence in northwest Montana (0.06) than in the remainder of the state (0.42). We also found both higher prevalence of E. schneideri and higher intensity to be correlated with increased probability of health-related mortality. Our results suggest presence and intensity of E. schneideri correlate with mortality of moose, although the mechanisms of mortality remain uncertain.

Origin of CO2 in Upper Devonian Duperow Formation and the Bakken Petroleum System at Kevin Dome, Northwest Montana

Carbon capture and storage (CCS) is a key mitigation strategy in achieving global net-zero emissions. It is therefore essential to identify and characterize potential subsurface storage repositories. Natural CO2 accumulations provide an opportunity to understand the behavior of CO2 in the subsurface. Here, we investigate the source(s), migration, and storage of CO2 in the Upper Devonian Duperow Formation at Kevin Dome, northwest Montana, USA within the Bakken Petroleum System. We report, major gas, stable and noble gas isotopic compositions in bulk gas samples (n = 19) produced from nearby hydrocarbon-bearing reservoirs at Kevin Dome and compare with CO2 bearing fluid inclusions (n = 24) from the Duperow Formation. Using the same methods, bulk gas samples (n = 9) from the adjacent Ferguson Field, (Exshaw/Bakken Petroleum System) in southern Alberta, Canada, and fluid inclusions from the Sweetgrass Hills igneous complex (n = 2) were analyzed to understand CO2 generation and the subsequent processes affecting CO2 regionally. We find that CO2 in the Upper Devonian Duperow Formation is magmatic in origin, likely related to the nearby Sweetgrass Hills igneous complex intrusion (∼52 Ma), whereas CH4 and N2 gases are generated predominantly by thermogenic processes associated with hydrocarbon generation during burial. Since emplacement, most CO2 in the hydrocarbon-bearing reservoirs of the Bakken petroleum system at Kevin Dome (∼98%) and the Ferguson Field (∼82%) has subsequently been dissolved into the groundwater. We employ a solubility model to calculate minimum gas/water ratios in Kevin Dome and the Ferguson Field, which are consistent with more groundwater interaction and more dissolution at Kevin Dome. Understanding the subsurface processes affecting CO2 is critical for future CO2 storage site selection.

Exploring the Impacts of Protected Areas’ Attributes on Pediatric Health: The Case for Additional Research beyond Greenspace

An increasingly vast segment of the literature examines the relationship between greenspace and pediatric health. However, the bulk of this research continues to use proximate relative greenness as a measure for exposure to the ecosystem services provisioned by natural areas, despite increasing recognition that relative greenness fails to capture the public accessibility, recreation potential, or desirability of natural areas. Thus, this present research demonstrates the use of emerging data sources that can be used in conjunction with traditional greenspace measures to improve modeling as it relates to nature’s impacts on pediatric health. Using spatial park and protected area data in concert with mobile phone location data, we demonstrate exploratory analysis on how park and protected area attributes may influence pediatric health in northwest Montana, USA. Suggestive findings concerning how the attributes of park and protected areas (i.e., conservation status, access, recreation demand) influence pediatric health (i.e., attention-deficit/hyperactivity disorder, asthma, and anxiety/mood disorders) lead us to introduce directions for future research beyond greenspace. Importantly, this research does not intend to provide definitive or generalizable findings concerning how parks and protected areas influence pediatric health. Instead, we aim to provide an initial exploration toward a larger, future body of the literature, evaluating parks and protected areas’ influence on pediatric health.

Grizzly bear habitat selection across the Northern Continental Divide Ecosystem

Understanding habitat selection is challenging but key for species of conservation concern, including grizzly bears (Ursus arctos). Here we demonstrate an approach for understanding and predicting habitat use over multiple stages that test hypotheses of animal behavior, use newly gained knowledge to mechanistically simulate individual movements, translate results to predictive habitat maps, and test their predictive power across a large spatiotemporal scale. Grizzly bears in the Northern Continental Divide Ecosystem of northwest Montana served as our study system. Mechanistically modeling grizzly bear movements demonstrated that grizzly bears have highly individualistic spatial behaviors. Some individuals avoided whereas others preferred areas of vegetation green-up, terrain ruggedness, forest edge, riparian areas, building densities, and secure habitat. Such individualism supported the need for an individual-based modeling approach to understand and predict grizzly bear behavior. External validation using >375,000 GPS locations for 261 individuals over nearly 2 decades demonstrated mean Spearman rank scores of >0.90 across seasons and years, and overall scores of 1.0. The top 5 classes of our predictive habitat maps contained 73.5 % of female fixes and 83.6 % of male fixes, and the top class (comprising 10 % of mapped area) contained 25.6 % and 41.7 % of female and male fixes, respectively. Results of this research provide tools for conservation planning and serve as the basis for future grizzly bear research within our study system and beyond. Our multi-stage approach for understanding and predicting habitat use has high utility for conservation of myriad threatened species around the globe.

Recognizing societal influences in earthquake geohazard risk perception with explainable AI while mitigating risks through improved seismic interpretation

As public awareness of climate-change-related weather events and temperature anomalies increases in the United States, citizens’ attitudes toward climate change should be studied, including the effects of climate mitigation strategies and their associated risks such as induced seismicity. Using social survey data and earthquake records, an explainable artificial intelligence method (SHAP) is employed to investigate factors that are important in explaining individual perceptions and assessments of future induced seismicity. Focusing on Oklahoma, where the majority (greater than 75%) of earthquakes are induced, SHAP reveals that personally experiencing earthquakes is a significant factor in the respondents’ past and future perception of earthquake frequency. Realizing that induced seismicity plays a strong role in individual perceptions of earthquake frequency, it is increasingly important to mitigate this geohazard, which is expected to increase with climate mitigation strategies, whether they are carbon capture and sequestration or geothermal in nature. To this end, seismic attribute methods to improve subsurface characterization, particularly for fluid migration pathway identification, are examined using data from a carbon sequestration project in northwest Montana in the Kevin Dome area. While broadband and multispectral coherence do not improve the identification of faults and fractures, in this case, aberrancy (the third derivative of structure) successfully highlights lineations because it is more susceptible to detecting flexures in seismic data. Based on this result, we strongly encourage interpreters to include aberrancy in their reservoir analysis to identify and mitigate fluid migration that may result in induced seismicity.

Climate, habitat interactions, and mule deer resource selection on winter landscapes

AbstractMule deer (Odocoileus hemionus) are a valued game species across their range in North America. At higher latitudes mule deer inhabit the Northern Forests ecoregion, where the winter season poses challenging conditions. We studied resource selection during winter by mule deer in northwest Montana, USA, focused on the effects of snow and canopy cover on deer behavior. Specifically, we assessed the effects of land cover type, terrain characteristics, snow accumulation, percent canopy cover, solar radiation, and forage biomass on resource selection by 126 mule deer captured during 2017–2019 in 3 partially migratory subpopulations. We collected pellet samples and conducted diet analyses to assess forage species by individual and study area. Deer displayed a shift from nitrogen‐rich forbs and shrubs in summer to nutrient‐poor evergreens like conifers in winter. Deer avoided areas with deeper snow and sought more closed canopy forests for their snow‐intercept advantages. Weather and vegetative variation among and within study areas resulted in disparities in selection for attributes such as land cover. Similarly, mule deer diets varied spatiotemporally as a function of snow, with some deer favoring coniferous species in deep snow, whereas others less constrained by snow had more diverse diets with more shrub species. Additional analyses revealed annual individual survival correlated with changes in snow depth, suggesting fitness consequences as snow accumulated. These differences suggest locally adapted behaviors as mule deer reflect energetic constraints of winter landscapes.

COVID-19 and food insecurity in the Blackfeet Tribal Community.

To examine the impact of the COVID-19 pandemic on food insecurity in the Blackfeet American Indian Tribal Community. American Indian adults residing on the Blackfeet reservation in Northwest Montana (n = 167) participated in a longitudinal survey across 4 months during the COVID-19 pandemic (August 24, 2020- November 30, 2020). Participants reported on demographics and food insecurity. We examined trajectories of food insecurity alongside COVID-19 incidence. While food insecurity was high in the Blackfeet community preceding the pandemic, 79% of our sample reported significantly greater food insecurity at the end of the study. Blackfeet women were more likely to report higher levels of food insecurity and having more people in the household predicted higher food insecurity. Longitudinal data indicate that the COVID-19 pandemic exacerbated already high levels of food insecurity in the Blackfeet community. Existing programs and policies are inadequate to address this public health concern in AI tribal communities.

Landscape Connectivity and Genetic Structure in a Mainstem and a Tributary Stonefly (Plecoptera) Species Using a Novel Reference Genome.

Understanding how environmental variation influences population genetic structure can help predict how environmental change influences population connectivity, genetic diversity, and evolutionary potential. We used riverscape genomics modeling to investigate how climatic and habitat variables relate to patterns of genetic variation in 2 stonefly species, one from mainstem river habitats (Sweltsa coloradensis) and one from tributaries (Sweltsa fidelis) in 40 sites in northwest Montana, USA. We produced a draft genome assembly for S. coloradensis (N50 = 0.251 Mbp, BUSCO > 95% using "insecta_ob9" reference genes). We genotyped 1930 SNPs in 372 individuals for S. coloradensis and 520 SNPs in 153 individuals for S. fidelis. We found higher genetic diversity for S. coloradensis compared to S. fidelis, but nearly identical genetic differentiation among sites within each species (both had global loci median FST = 0.000), despite differences in stream network location. For landscape genomics and testing for selection, we produced a less stringently filtered data set (3454 and 1070 SNPs for S. coloradensis and S. fidelis, respectively). Environmental variables (mean summer precipitation, slope, aspect, mean June stream temperature, land cover type) were correlated with 19 putative adaptive loci for S. coloradensis, but there was only one putative adaptive locus for S. fidelis (correlated with aspect). Interestingly, we also detected potential hybridization between multiple Sweltsa species which has never been previously detected. Studies like ours, that test for adaptive variation in multiple related species are needed to help assess landscape connectivity and the vulnerability of populations and communities to environmental change.

Resolving the Cenozoic History of Rock Exhumation Along the Central Rocky Mountain Trench Using Apatite Low‐Temperature Thermochronology

AbstractThe Rocky Mountain Trench (RMT) extends through the Canadian Cordillera from the Yukon to northwest Montana. The RMT's impressive length and continuous nature have been interpreted to be the result of faulting, and localized erosion, along a continent‐scale zone of crustal weakness located beneath the RMT, possibly associated with the ancient continental margin. Despite the continuous nature of the RMT, its kinematics vary along strike from dextral strike‐slip faults in the north to normal faults in the south. The central RMT is thought to be the transition between these two structural zones. We use low‐temperature thermochronology to compare the cooling histories across the central RMT in eastern British Columbia. We report apatite fission track ages from 23 samples and apatite (U‐Th)/He ages from 25 samples along with thermal‐history models. Our results reveal three phases of rapid cooling that followed the Cretaceous‐Paleocene cordilleran thrusting in the Eocene, the early–mid Miocene, and from the late Miocene to recent. We find that the Malton Gneiss Complex exhumed as a horst structure 20–10 Ma bounded by the North Thompson Albreda Fault and the RMT. Normal faulting along the NTAF continued in the late Miocene as well as west side down normal faulting along the RMT. Our data suggest that extends along the southern RMT continued northward to at least this portion of the central RMT in multiple episodes during the Cenozoic. We suggest transtension occurred in our study area that was driven by orogenic collapse and lithospheric mantle delamination.

Migratory Connectivity and Nesting Behavior in Harlequin Ducks (Histrionicus histrionicus) Based on Light-Level Geolocator Data

The Harlequin Duck (Histrionicus histrionicus) is a species of conservation priority in western North America. Harlequin Ducks breed in small, isolated populations and have specific nesting requirements. Archival, light-level geolocators are increasingly being used as a low-cost, non-invasive tracking technology to explore migratory connectivity. From 2015-2019, geolocators were deployed on 70 Harlequin Ducks in breeding streams of the Rocky Mountains, Canada and USA, to obtain information on connectivity (breeding to non-breeding), molt-winter sites, dispersal, and breeding phenology. Twenty-two of the 70 geolocators were retrieved from locations in the Rocky Mountains (Alberta, Canada; Montana and Wyoming, USA) and analyzed using the TwGeos and FLightR R packages. Harlequin Ducks from the warmer climate of northwest Montana migrated in spring and started incubation one to two weeks earlier than ducks in west-central Alberta and the greater Yellowstone area. During the non-breeding period, individuals dispersed along the Pacific coast, from Oregon to the Alaskan Panhandle, independent of breeding site. Females that incubated successfully spent 32-34 days incubating, which is several days longer than what is in the literature. Use of geolocators provided detailed information about migration connectivity and breeding behavior in a cost effective and relatively non-invasive manner.

Climate drivers of large magnitude snow avalanche years in the U.S. northern Rocky Mountains

Large magnitude snow avalanches pose a hazard to humans and infrastructure worldwide. Analyzing the spatiotemporal behavior of avalanches and the contributory climate factors is important for understanding historical variability in climate-avalanche relationships as well as improving avalanche forecasting. We used established dendrochronological methods to develop a long-term (1867–2019) regional avalanche chronology for the Rocky Mountains of northwest Montana using tree-rings from 647 trees exhibiting 2134 avalanche-related growth disturbances. We then used principal component analysis and a generalized linear autoregressive moving average model to examine avalanche-climate relationships. Historically, large magnitude regional avalanche years were characterized by stormy winters with positive snowpack anomalies, with avalanche years over recent decades increasingly influenced by warmer temperatures and a shallow snowpack. The amount of snowpack across the region, represented by the first principal component, is shown to be directly related to avalanche probability. Coincident with warming and regional snowpack reductions, a decline of ~ 14% (~ 2% per decade) in overall large magnitude avalanche probability is apparent through the period 1950–2017. As continued climate warming drives further regional snowpack reductions in the study region our results suggest a decreased probability of regional large magnitude avalanche frequency associated with winters characterized by large snowpacks and a potential increase in large magnitude events driven by warming temperatures and spring precipitation.

Structural diversity and development in active fire regime mixed-conifer forests

Nearly a century of fire suppression in most forested land of the United States has limited researchers’ ability to construct and rigorously test conceptual models of forest structural development in mixed-conifer ecosystems. As a result, land managers must rely on conceptual models of forest development that may overemphasize idealized stand structures and developmental pathways, which ultimately hampers management of many forest systems for resilience to future climate change impacts. We sought to determine the relative importance of fire history (frequency, severity, and time since fire) and biophysical variables on forest structural diversity and development. Importantly, we conducted our study in an ecosystem with a contemporary active fire regime where wildland fire has been managed as an ecosystem process for four decades. Using data from unburned (≥80 years since fire), once-burned and twice-burned mixed-conifer forests in the Bob Marshall Wilderness of Northwest Montana, we conducted a hierarchical clustering analysis to identify forest stand structure classes. We then used a Classification and Regression Tree analysis, combined with other post-hoc analyses, to elucidate the biophysical and disturbance history drivers that lead to each structure class. The cluster analysis revealed six forest structure classes. The CART analysis indicated that time since fire plays a large role in determining forest structure, but at intermediate time scales structure is further shaped by repeat fires and interactions with biophysical variables. The CART and post-hoc analyses did not, however, indicate a singular fire history or biophysical pathway to any one structure class. We synthesize our results in a conceptual model of forest structural development under an active fire regime. This model supports existing theory that succession following severe fire plays a large role in shaping forest structure. It also recognizes the role of fire at variable severities and frequencies, the physical environment, and tree community composition in influencing forest structural development. The complexity of forest structure and development generated by an active fire regime points to the need to incorporate a process-based view of wildfire if the goal is to manage for improved resiliency and adaptive capacity to future climate change impacts.

Genomic data reveal similar genetic differentiation in aquifer species with different dispersal capabilities and life histories

Abstract Little is known about the life histories, genetic structure and population connectivity of shallow groundwater organisms. We used next-generation sequencing (RAD-seq) to analyse population genomic structure in two aquifer species: Paraperla frontalis (Banks, 1902), a stonefly with groundwater larvae and aerial (winged) adults; and Stygobromus sp., a groundwater-obligate amphipod. We found similar genetic differentiation in each species between floodplains separated by ~70 river km in the Flathead River basin of north-west Montana, USA. Given that Stygobromus lacks the above-ground life stage of P. frontalis, our findings suggest that connectivity and the magnitude of genetic structure cannot be definitively assumed from life history differences.

A winter energetics model for bobcats in a deep snow environment

Understanding basic energetic requirements of wildlife species is critical to evaluate how individuals persist in their current environments as well as to forecast responses to changed climates or habitats. Indeed, northern range limits are often thought to reflect harsh abiotic conditions that exceed the capacity of individuals to stay in energetic balance. Bobcats (Lynx rufus) occur across much of North America; at northern latitudes, they face winter challenges such as deep snows, cold temperatures, and possible food scarcity. We developed an energetics model from field data on movements, body mass, and observed diet of bobcats in mountains of northwest Montana, then evaluated overwinter prey requirements that would enable bobcats to stay in energy balance in this difficult environment. Our model indicated average daily energy expenditures were ~ 1.41× basal metabolic rate. For 90 days from December to February, a 10.5 kg bobcat consuming prey items in proportion with the observed diet for bobcats in this area would need about 2.1 kg of deer (Odocoileus spp.), 7 snowshoe hares (Lepus americanus), 155 red squirrels (Tamiasciurus hudsonicus), 9 woodrats (Neotoma cinerea), and 250 small rodents (Cricetidae). Bobcats have considerable flexibility in diet, movements, and both timing and duration of daily activity to adjust their energetic expenditures in winter.

Revisiting the equable climate problem during the Late Cretaceous greenhouse using paleosol carbonate clumped isotope temperatures from the Campanian of the Western Interior Basin, USA

Greenhouse climates such as the Late Cretaceous period provide important reference frames for understanding modern anthropogenic climate change. Upper Cretaceous terrestrial climate proxies have been interpreted as evidence for “equable” climates with reduced seasonal variations in temperature. However, climate models have largely failed to reproduce these reconstructions unless parameters such as atmospheric CO2 concentrations are set to unreasonable values. To help resolve such model-proxy disagreements, we reconstruct mean annual range in temperature (MART) for the Campanian (~75 Ma) Kaiparowits (south-central Utah) and Two Medicine (northwest Montana) Formations using warmest mean monthly temperature reconstructions from the clumped isotope composition of paleosol carbonate nodules, and reconstructions of local mean annual air temperatures from other methods. An evaluation of the applicability of bulk elemental soil geochemistry temperature proxies in these deposits supports the use of previous leaf physiognomy-based estimates of mean annual temperature for our MART reconstructions. We test the validity of several common assumptions made in reconstructing MART in two novel ways. First, MART is commonly calculated as twice the difference between local mean annual air temperature and warmest mean monthly temperature, and we validate this method by estimating modern MART for a range of environments using climate reanalysis data. Second, we constrain the effect of radiative soil heating on our soil carbonate temperature estimates by showing that for most environments likely to be preserved in the geologic record, summer soil temperatures are <3 °C higher than air temperatures. Our findings suggest that warmest mean monthly temperatures were 30 to 35 ± 4 °C at the two study sites, and that MART was 21 to 29 °C for the Kaiparowits Formation, and 21 to 27 °C for the Two Medicine Formation. Mid-latitude Late Cretaceous MARTs were similar to modern ranges in mid-latitude seasonal temperature, and much (>9 °C) larger than previous proxy reconstructions of Late Cretaceous MART. These results add to a growing body of literature showing that terrestrial MART during ancient greenhouse periods was not significantly different from modern seasonal temperature variations. Finally, the similarity in MART between the Kaiparowits and Two Medicine formations suggests that latitudinal changes in MART did not contribute to the faunal provincialism that has been proposed by some paleontologists.

The effects of agent hybridization on the efficacy of biological control of tansy ragwort at high elevations.

The success rate of weed biological control programs is difficult to evaluate and the factors affecting it remain poorly understood. One aspect which is still unclear is whether releases of multiple, genetically distinct populations of a biological control agent increase the likelihood of success, either by independent colonization of different environmental niches or by hybridization that may increase the agent's fitness and adaptive ability. Since hybridization is often invoked to explain the success of unintentionally introduced exotic species, hybridization among biocontrol agents may be similarly important in shaping the effectiveness of biological control programs. In this study, we first evaluated intraspecific hybridization among populations of a weed biological control agent, the ragwort flea beetle, Longitarsus jacobaeae. These insects were introduced as part of a classical biological control program from Italy and Switzerland. We genotyped 204 individuals from 15 field sites collected in northwest Montana, and an additional 52 individuals that served as references for Italian and Swiss populations. Bayesian analysis of population structure assigned seven populations as pure Swiss and one population as pure Italian, while intraspecific hybrid individuals were detected in seven populations at frequencies of 5%–69%. Subsequently, we conducted a 2‐year exclusion experiment using six sites with Swiss beetles and three with hybrid beetles to evaluate the impact of biological control. We found that biological control by Swiss beetles and by hybrid beetles is effective, increasing mortality of the target plant, Jacobaea vulgaris, by 42% and 45%, and reducing fecundity of surviving plants by 44% and 72%, respectively. Beetle densities were higher and mortality of larger plants was higher at sites with hybrids present. These results suggest that hybridization of ragwort flea beetles at high‐elevation sites may improve biological control of tansy ragwort and that intraspecific hybridization of agents could benefit biological control programs.