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Tabitha A. Graves

Publications and source records attributed to Tabitha A. Graves.

At least 37 records · Page 2Linked to original sources
USGS2025

Evaluating mountain goat population structure in Glacier National Park and Waterton Lakes National Park

Mountain goats are an iconic, climate-sensitive species across their North American alpine range. Among its nearly complete complement of native wildlife, no single species embodies Glacier National Park (GNP) more than the mountain goat. They play an important role as an alpine food source for many of the park’s carnivores including wolverines, mountain lions, and grizzly bears. Mountain goats face many increasing threats, particularly at the southern extent of their range. These include changes in precipitation and temperature, shifts in forage and fire frequency and intensity, and rapidly increasing visitation and recreation. Although the high latitude and elevations of GNP offer refugia, the mountain goat population likely declined between 2008 and 2019 and may also have a smaller distribution. In Montana, many other native mountain goat populations are also declining or have disappeared entirely. Using a combination of staff and citizen scientists, we collected fecal pellets across GNP in Montana, USA, and adjoining Waterton Lakes National Park (WLNP) in Alberta, Canada, between 2019 and 2023. We used genotypes of 6 to 19 loci microsatellites to identify individuals and assess isolation by distance, genetic structure, and genetic diversity. We found no evidence of genetic structure and only limited isolation by distance. This suggests that mountain goats in GNP and WLNP can be considered a single population, so samples can be combined across the area to estimate a single population size. Genetic diversity was similar to recent mountain goat studies conducted in other regions; allelic richness was 3.54 and inbreeding coefficients ( F IS ) ranged from 0.01–0.19, with values >0.11 only in the Livingston Range in the northwest of the study area. The high F IS in the Livingston Range suggests several closely related groups with little interchange, and perhaps a recent decrease in gene flow, both of which are consistent with a recent population decline in that area. We detected a high number of closely related individuals throughout our study area, consistent with the high adult survival, low reproductive success life history of goats, but also suggesting that we sampled much of the overall population.

Alberta, Montana↗
USGS2025

Assessing diet and genotyping success of goat pellet surveys from 2019 in Glacier National Park

Fecal pellets contain genetic information and can be used to identify individuals, their diet, and more. Individual identification can be useful in understanding movements of individuals, developing population estimates, assessing vital rates, genetic diversity and structure, and evaluating trends over time (e.g., Epps et al 2024). Successful genotyping depends on the quality of the sample, which can be influenced by many things including the initial state of the sample, environmental conditions that the pellets were exposed to, and the method of storage. The diet of mountain goats ( Oreamnos americanus ) is hard to study as they are habitat specialists in some of the most remote and rugged alpine environments (Festa-Bianchet & Côté 2012). These iconic ungulates epitomize the renowned wilderness character of Glacier National Park (GNP), yet the population has declined by 45% since 2008 likely due at least in part to changing climate (Graves et al. 2025). This is well above the International Union for the Conservation of Nature’s population decline criterion used to designate a species as vulnerable (IUCN 2012). Mountain goats are known as dietary generalists employing highly variable diets across systems, but diets have not been identified for GNP. Identifying goat diet composition in GNP can provide the information needed to determine whether this population decline could be related to climate-change induced shifts in forage phenology, diversity, productivity, and plant community structure. Other anthropogenic changes in GNP, such as increases in exotic and invasive plant species, will continue to affect plant community composition (Lesica et al. 1993). These alterations may reduce optimal forage availability and quality, which could have a deleterious effect on mountain goat survival. To examine these possibilities, we must first ask- What precisely are the mountain goats of Glacier National Park eating? DNA metabarcoding of fecal pellets provides a cutting-edge, non-invasive method for assessing herbivore diet. Previous studies of mountain goat diet have used methods such as fecal crude protein analysis (Festa-Bianchet & Côté 2012), rumen analysis (Saunders 1955), fecal microhistology (Cobb et al. 2012), and bite-for-bite feeding observations (Daily et al. 1984). Many of these studies have only been able to identify diet components to functional plant type and the methods used are biased towards less digestible diet components such as grasses (McInnis et al. 1983). Metabarcoding of fecal pellets can provide a higher taxonomic resolution than previous methods (Scasta et al. 2019, Stapleton et al. 2022) and open the field for increased participation of volunteers, also called community or citizen scientists. Here, we use mountain goat fecal pellets to conduct 1) an evaluation of which conditions might influence genotyping success and 2) a preliminary assessment of diet using metabarcoding. This pilot study allowed us to evaluate which pellets to focus on collecting, identify the best storage methods, explore approaches for analyzing metabarcoding data, examine the utility of metabarcoding for acquiring taxonomically specific diet information, and to identify genetic sequences that could not be resolved to genus or species levels using these methods. We examined the frequency of occurrence and relative diet composition of identified forbs, shrubs, graminoids, mosses, and trees in mountain goat diets.

Montana↗
USGS2024

Population and spatial dynamics of desert bighorn sheep in Grand Canyon during an outbreak of respiratory pneumonia

Introduction: Terrestrial species in riverine ecosystems face unique constraints leading to diverging patterns of population structure, connectivity, and disease dynamics. Desert bighorn sheep ( Ovis canadensis nelsoni ) in Grand Canyon National Park, a large native population in the southwestern USA, offer a unique opportunity to evaluate population patterns and processes in a remote riverine system with ongoing anthropogenic impacts. We integrated non-invasive, invasive, and citizen-science methods to address questions on abundance, distribution, disease status, genetic structure, and habitat fragmentation. Methods: We compiled bighorn sightings collected during river trips by park staff, commercial guides, and private citizens from 2000–2018 and captured bighorn in 2010–2016 to deploy GPS collars and test for disease. From 2011–2015, we non-invasively collected fecal samples and genotyped them at 9–16 microsatellite loci for individual identification and genetic structure. We used assignment tests to evaluate genetic structure and identify subpopulations, then estimated gene flow and recent migration to evaluate fragmentation. We used spatial capture-recapture to estimate annual population size, distribution, and trends after accounting for spatial variation in detection with a resource selection function model. Results and discussion: From 2010–2018, 3,176 sightings of bighorn were reported, with sightings of 56–145 bighorn annually on formal surveys. From 2012–2016, bighorn exhibiting signs of respiratory disease were observed along the river throughout the park. Of 25 captured individuals, 56% were infected by Mycoplasma ovipneumoniae , a key respiratory pathogen, and 81% were recently exposed. Pellet sampling for population estimation from 2011–2015 yielded 1,250 genotypes and 453 individuals. We detected 6 genetic clusters that exhibited mild to moderate genetic structure ( F ST 0.022–0.126). The river, distance, and likely topography restricted recent gene flow, but we detected cross-river movements in one section via genetic recaptures, no subpopulation appeared completely isolated, and genetic diversity was among the highest reported. Recolonization of one large stretch of currently empty habitat appears limited by the constrained topology of this system. Annual population estimates ranged 536–552 (95% CrI range 451–647), lamb:ewe ratios varied, and no significant population decline was detected. We provide a multi-method sampling framework useful for sampling other wildlife in remote riverine systems.

Arizona↗
USGS2024

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

Background Improved 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. Methods We 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. Results Model results indicated that landscape structure influences black bear density and space use in Glacier. The mean density estimate was 16.08 bears/100 km 2 (95% CI 12.52–20.6) for females and 9.27 bears/100 km 2 (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. Conclusions Density-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.

Montana↗
USGS2024

Quantifying effectiveness and best practices for bumblebee identification from photographs

Understanding pollinator networks requires species level data on pollinators. New photographic approaches to identification provide avenues to data collection that reduce impacts on declining bumblebee species, but limited research has addressed their accuracy. Using blind identification of 1418 photographed bees, of which 561 had paired specimens, we assessed identification and agreement across 20 bumblebee species netted in Montana, North Dakota, and South Dakota by people with minimal training. An expert identified 92.4% of bees from photographs, whereas 98.2% of bees were identified from specimens. Photograph identifiability decreased for bees that were wet or matted; bees without clear pictures of the abdomen, side of thorax, or top of thorax; bees photographed with a tablet, and for species with more color morphs. Across paired specimens, the identification matched for 95.1% of bees. When combined with a second opinion of specimens without matching identifications, data suggested a similar misidentification rate (2.7% for photographs and 2.5% specimens). We suggest approaches to maximize accuracy, including development of rulesets for collection of a subset of specimens based on difficulty of identification and to address cryptic variation, and focused training on identification that highlights detection of species of concern and species frequently confused in a study area.

Scientific Reports↗
USGS2024

Ungulate personality and the human shield contribute to long-distance migration loss

Long-distance ungulate migrations are declining and past research has focused on preserving migration paths where habitat fragmentation and loss disrupts movement corridors. However, changing residency-migration tradeoffs are the stronger driver of long-distance migration loss in some populations. The human shield effect relative to predation risk and anthropogenic food resources likely shapes these tradeoffs, but individual animals also vary in their propensity to tolerate proximity to humans and developed areas. We investigated how personality relative to human-habituation affects migration behavior. We categorized elk as bold or shy based on use of anthropogenic food resources identified through a clustering algorithm applied to GPS collar data. Bold elk were 4 times more likely to select wintering areas close to human activity and migrated 60% shorter distances compared to shy elk. As a result, elk wintering grounds were spatially structured such that conflict- and disease-prone individuals selected areas adjacent to human activity. Our results suggest that bold personality traits act as a precursor to human-habituation, which permits bold elk to reap the forage and predation rewards that occur in suburban landscapes. A multi-pronged approach beyond just maintaining habitat corridors may be necessary to conserve long-distance migrations for species that can become human-habituated.

BioRxiv↗
USGS2024

Glacier National Park bumble bee survey report 2023

Glacier National Park's grasslands provide important contributions to the character and ecology of the park. In 1999-2001, Glacier National Park (hereafter, the park) established 155 permanent vegetation monitoring plots to inventory grassland vegetation communities east of the Continental Divide. In June of 2023, the Blackfeet Nation (Amskapi Piikuni) re-introduced a herd of free roaming bison on adjacent tribal land (the linnii Initiative), and those bison may enter the park. Because grasslands are important areas for bison grazing, and because biological communities have likely changed since the initial inventories, the park’s vegetation program began revisiting grassland monitoring plots in 2018. New data will provide insights into how these grasslands, and the wildlife that depend on them, have changed over the past two decades. Data on pollinators in these grasslands, however, are limited. Bison have been shown to influence plant communities, for example, by increasing herbaceous forb diversity and drought resilience (Elson and Hartnett 2017; Ratajczak et al. 2022). These changes directly influence resources available to foraging pollinators. To provide understanding of pollinators prior to bison reintroduction, bumble bee surveying at these grassland plots began in 2020 and has continued through 2023. Target sites for 2020-2022 focused on collecting data at plots where new vegetation surveys were recently completed to match current vegetation data with the bumble bee data.

Montana↗
USGS2024

Western and McKay's bumble bees occupancy trends and future projections

The Western and McKay's bumble bees, originally petitioned for listing as subspecies of the Western bumble bee (Bombus occidentalis) were previously among the most common western bumble bee species but have declined since the late 1990s (Graves et al. 2021). This report details an occupancy analysis utilizing pre-existing and newly collected bumble bee survey data to evaluate potential mechanisms associated with species trends across their distributions in western North America. In addition to evaluating spatially explicit changes in occupancy trends, we also sought to assess how widespread environmental conditions and stressors influence occupancy. Although changing climate, land cover, pesticides, and pathogens have all been identified as potential mechanisms for declines (Cameron et al. 2011, Kerr et al. 2015, Soroye et al. 2020), previous studies have not tied most climate hypotheses to bumble bee life histories or evaluated combined effects of more than 2 of these mechanisms at multi-state/ multiprovince scales. Using a scenario-based approach across climate models, emissions, and land cover scenarios, we projected future occupancy to mid-century (2050-2059). This analysis was conducted to support the Species Status Assessment (SSA) for Western and Mckay’s bumble bees being administered by the U.S. Fish & Wildlife Service (USFWS).

Report↗
USGS2023

Bighorn sheep associations: Understanding tradeoffs of sociality and implications for disease transmission

Sociality directly influences mating success, survival rates, and disease, but ultimately likely evolved for its fitness benefits in a challenging environment. The tradeoffs between the costs and benefits of sociality can operate at multiple scales, resulting in different interpretations of animal behavior. We investigated the influence of intrinsic ( e.g. , relatedness, age) and extrinsic factors ( e.g. , land cover type, season) on direct contact (simultaneous GPS locations ≤ 25 m) rates of bighorn sheep ( Ovis canadensis ) at multiple scales near the Waterton-Glacier International Peace Park. During 2002–2012, male and female bighorn were equipped with GPS collars. Indirect contact (GPS locations ≤ 25 m regardless of time) networks identified two major breaks whereas direct contact networks identified an additional barrier in the population, all of which corresponded with prior disease exposure metrics. More direct contacts occurred between same-sex dyads than female-male dyads and between bighorn groups with overlapping summer home ranges. Direct contacts occurred most often during the winter-spring season when bighorn traveled at low speeds and when an adequate number of bighorn were collared in the area. Direct contact probabilities for all dyad types were inversely related to habitat quality, and differences in contact probability were driven by variables related to survival such as terrain ruggedness, distance to escape terrain, and canopy cover. We provide evidence that probabilities of association are higher when there is greater predation risk and that contact analysis provides valuable information for understanding fitness tradeoffs of sociality and disease transmission potential.

Alberta, British Columbia, Montana↗
USGS2023

Ecological significance of Wild Huckleberries (Vaccinium membranaceum)

Wild huckleberry ( Vaccinium globare/membranaceum complex) is a keystone species in the Pacific Northwest of the United States. The fruits are a primary food source for grizzly bears and other wildlife, as well as an important traditional and contemporary human food. Huckleberry shrubs also provide cover and nesting habitat for many animal species, including small mammals and birds. The flowers provide nectar and pollen with crucial connections between bumble bees ( Bombus species) and huckleberries. Native bee pollination is essential for successful berry development. Huckleberries flower early in the growing season and are some of the only floral resources available when bumble bee queens first emerge from hibernation and need to collect pollen and nectar for nesting. One of these species, the Western bumble bee ( Bombus occidentalis ), is in review for listing under the U.S. Endangered Species Act. Future climate change has the potential to influence huckleberry distribution, productivity, and phenology. These potential changes could have wide-ranging implications because of the economic, cultural, and ecological importance of huckleberry.

Book chapter↗
USGS2023

Recent and future declines of a historically widespread pollinator linked to climate, land cover, and pesticides

The acute decline in global biodiversity includes not only the loss of rare species, but also the rapid collapse of common species across many different taxa. The loss of pollinating insects is of particular concern because of the ecological and economic values these species provide. The western bumble bee ( Bombus occidentalis ) was once common in western North America, but this species has become increasingly rare through much of its range. To understand potential mechanisms driving these declines, we used Bayesian occupancy models to investigate the effects of climate and land cover from 1998 to 2020, pesticide use from 2008 to 2014, and projected expected occupancy under three future scenarios. Using 14,457 surveys across 2.8 million km 2 in the western United States, we found strong negative relationships between increasing temperature and drought on occupancy and identified neonicotinoids as the pesticides of greatest negative influence across our study region. The mean predicted occupancy declined by 57% from 1998 to 2020, ranging from 15 to 83% declines across 16 ecoregions. Even under the most optimistic scenario, we found continued declines in nearly half of the ecoregions by the 2050s and mean declines of 93% under the most severe scenario across all ecoregions. This assessment underscores the tenuous future of B. occidentalis and demonstrates the scale of stressors likely contributing to rapid loss of related pollinator species throughout the globe. Scaled-up, international species-monitoring schemes and improved integration of data from formal surveys and community science will substantively improve the understanding of stressors and bumble bee population trends.

Proceedings of the National Academy of Sciences↗
USGS2022

A statistical framework for modelling migration corridors

1. Management of animal populations requires spatially explicit knowledge of movement corridors, such as those used during seasonal migrations. GPS tracking data allows for mapping of corridors from directly observed movements, providing important insights, but tracking data is absent for many populations. 2. We developed a novel statistical corridor modeling approach that predicts movement corridors from cost-distance movement models fit directly to migration tracking data. Unlike existing predictive approaches, this does not require the ad-hoc transformation of habitat suitability surfaces into resistance surfaces. We tested the ability of the approach to recover parameters used to generate simulated movements. We then used GPS data from three migrating mule deer (Odocoileus hemionus) herds in Idaho and Wyoming to model corridors as a function of elevation, slope, aspect, percent shrub, date of peak green-up, snow-off date, and human footprint. We assessed the predictive ability of the fitted models using validation tracks from the same herd as well as from the other herds. 3. The approach reproduced parameters used to generate the simulated movements, predicted the corridors used by migratory populations, and described the direction, magnitude, and confidence levels of the effects of environmental variables on corridors. The effects environmental variables had on corridors differed depending on the herd. Within-herd validation indicated that fitted corridor models are more accurate at predicting migration corridors than null models, and cross-herd validation indicated that fitted models for some herds accurately predicted the observed migrations of other herds. 4. In addition to the practical benefit of mapping corridors for management, our statistical corridor modeling framework sets the stage for evaluating fundamental questions about the fitness tradeoffs, navigation, learning, fidelity, and movement constraints that influence migratory and other corridor-generating behavior. Models of predictive corridors can inform management and planning for the conservation of migrations across taxa, including the potential restoration of corridors. Our corridor modeling approach is also readily applied to non-migratory animal movements.

Idaho, Wyoming↗
USGS2022

Precision and bias of spatial capture–recapture estimates: A multi-site, multi-year Utah black bear case study

Spatial capture–recapture (SCR) models are powerful analytical tools that have become the standard for estimating abundance and density of wild animal populations. When sampling populations to implement SCR, the number of unique individuals detected, total recaptures, and unique spatial relocations can be highly variable. These sample sizes influence the precision and accuracy of model parameter estimates. Testing the performance of SCR models with sparse empirical data sets typical of low-density, wide-ranging species can inform the threshold at which a more integrated modeling approach with additional data sources or additional years of monitoring may be required to achieve reliable, precise parameter estimates. Using a multi-site, multi-year Utah black bear ( Ursus americanus ) capture–recapture data set, we evaluated factors influencing the uncertainty of SCR structural parameter estimates, specifically density, detection, and the spatial scale parameter, sigma. We also provided some of the first SCR density estimates for Utah black bear populations, which ranged from 3.85 to 74.33 bears/100 km 2 . Increasing total detections decreased the uncertainty of density estimates, whereas an increasing number of total recaptures and individuals with recaptures decreased the uncertainty of detection and sigma estimates, respectively. In most cases, multiple years of data were required for precise density estimates (<0.2 coefficient of variation [CV]). Across study areas there was an average decline in CV of 0.07 with the addition of another year of data. One sampled population with very high estimated bear density had an atypically low number of spatial recaptures relative to total recaptures, apparently inflating density estimates. A complementary simulation study used to assess estimate bias suggested that when <30% of recaptured individuals were spatially recaptured, density estimates were unreliable and ranged widely, in some cases to >3 times the simulated density. Additional research could evaluate these requirements for other density scenarios. Large numbers of individuals detected, numbers of spatial recaptures, and precision alone may not be sufficient indicators of parameter estimate reliability. We provide an evaluation of simple summary statistics of capture–recapture data sets that can provide an early signal of the need to alter sampling design or collect auxiliary data before model implementation to improve estimate precision and accuracy.

Utah↗
USGS2022

Eyes on the herd: Quantifying ungulate density from satellite, unmanned aerial systems, and GPScollar data

Novel approaches to quantifying density and distributions could help biologists adaptively manage wildlife populations, particularly if methods are accurate, consistent, cost-effective, rapid, and sensitive to change. Such approaches may also improve research on interactions between density and processes of interest, such as disease transmission across multiple populations. We assess how satellite imagery, unmanned aerial system (UAS) imagery, and Global Positioning System (GPS) collar data vary in characterizing elk density, distribution, and count patterns across times with and without supplemental feeding at the National Elk Refuge (NER) in the US state of Wyoming. We also present the first comparison of satellite imagery data with traditional counts for ungulates in a temperate system. We further evaluate seven different aggregation metrics to identify the most consistent and sensitive metrics for comparing density and distribution across time and populations. All three data sources detected higher densities and aggregation locations of elk during supplemental feeding than non-feeding at the NER. Kernel density estimates (KDEs), KDE polygon areas, and the first quantile of interelk distances detected differences with the highest sensitivity and were most highly correlated across data sources. Both UAS and satellite imagery provide snapshots of density and distribution patterns of most animals in the area at lower cost than GPS collars. While satellite-based counts were lower than traditional counts, aggregation metrics matched those from UAS and GPS data sources when animals appeared in high contrast to the landscape, including brown elk against new snow in open areas. UAS counts of elk were similar to traditional ground-based counts on feed grounds and are the best data source for assessing changes in small spatial extents. Satellite, UAS, or GPS data can provide appropriate data for assessing density and changes in density from adaptive management actions. For the NER, where high elk densities are beneath controlled airspace, GPS collar data will be most useful for evaluating how management actions, including changes in the dates of supplemental feeding, influence elk density and aggregation across large spatial extents. Using consistent and sensitive measures of density may improve research on the drivers and effects of density within and across a wide range of species.

Wyoming↗
USGS2022

Average kinship within bighorn sheep populations is associated with connectivity, augmentation, and bottlenecks

Understanding the influence of population attributes on genetic diversity is important to advancement of biological conservation. Because bighorn sheep ( Ovis canadensis ) populations vary in size and management history, the species provides a unique opportunity to observe the response of average pairwise kinship, inversely related to genetic diversity, to a spectrum of natural and management influences. We estimated average pairwise kinship of bighorn sheep herds and compared estimates with population origin (native/indigenous/extant or reintroduced), historical minimum count, connectivity, and augmentation history, to determine which predictors were the most important. We evaluated 488 bighorn sheep from 19 wild populations with past minimum counts of 16–562 animals, including native and reintroduced populations that received 0–165 animals in augmentations. Using the Illumina High Density Ovine array, we generated a dataset of 7728 single nucleotide polymorphisms and calculated average pairwise kinship for each population. Multiple linear regression analysis determined that connectivity between populations via dispersal, greater number of animals received in augmentations, and greater minimum count were correlated with lower average pairwise kinship at the population level, and whether the population was extant or reintroduced was less important. Thus, our results indicated that genetic isolation of populations can result in increased levels of inbreeding. By determining that natural and human-assisted gene flow were likely the most important influences of average pairwise kinship at the population level, this study can serve as a benchmark for future management of bighorn sheep populations and aid in identifying populations of genetic concern to define priorities for conservation of wild populations.

Montana, Wyoming↗
USGS2021

U.S. Geological Survey science for the Wyoming Landscape Conservation Initiative—2018 annual report

The Wyoming Landscape Conservation Initiative (WLCI) was established in 2007 as a collaborative interagency partnership to develop and implement science-based conservation actions. During the past 11 years, partners from U.S. Geological Survey (USGS), State and Federal land management agencies, universities, and the public have collaborated to implement a long-term (more than 10 years) science-based program that assesses and enhances the quality and quantity of wildlife habitats in the southwest Wyoming region while facilitating responsible development. The USGS WLCI Science Team completes scientific research and develops tools that inform and support WLCI partner planning, decision making, and on-the-ground management actions. In fiscal year 2018, the USGS initiated 3 new projects and continued efforts on 21 ongoing science and web-development projects. The first new project was initiated to support Secretarial Order 3362 which calls on the USGS to assist Western States in mapping big-game migration corridors and developing new mapping tools. During 2018, the USGS hosted a workshop in Laramie, Wyoming, which included more than 70 State and Federal wildlife experts from Colorado, New Mexico, Texas, and Wyoming. Most of the mapping and migration tool curricula used in the workshop were derived from prior WLCI studies and mapping efforts of big-game migration movement in habitats undergoing large-scale energy development. The second new project was in response for WLCI partners to better understand sedimentation and hydrogeomorphic processes in a cold-desert headwater and the third new project was designed to improve our approach for people to access, manage, and analyze WLCI data and WLCI resource information. The USGS published 18 products (including peer-reviewed journal articles, USGS series publications, and data releases) and provided more than a dozen professional oral and poster presentations at scientific meetings and numerous informal presentations to WLCI partners at meetings and workshops. This report summarizes the objectives and status of each project and highlights the USGS 2018 accomplishments and products.

Wyoming↗
USGS2021

The smell of success: Reproductive success related to rub behavior in brown bears

Several species of bears are known to rub deliberately against trees and other objects, but little is known about why bears rub. Patterns in rubbing behavior of male and female brown bears ( Ursus arctos ) suggest that scent marking via rubbing functions to communicate among potential mates or competitors. Using DNA from bear hairs collected from rub objects in southwestern Alberta from 2011–2014 and existing DNA datasets from Montana and southeastern British Columbia, we determined sex and individual identity of each bear detected. Using these data, we completed a parentage analysis. From the parentage analysis and detection data, we determined the number of offspring, mates, unique rub objects where an individual was detected, and sampling occasions during which an individual was detected for each brown bear identified through our sampling methods. Using a Poisson regression, we found a positive relationship between bear rubbing behavior and reproductive success; both male and female bears with a greater number of mates and a greater number of offspring were detected at more rub objects and during more occasions. Our results suggest a fitness component to bear rubbing, indicate that rubbing is adaptive, and provide insight into a poorly understood behaviour.

Wyoming, Montana, British Columbia, Alberta↗