Browsing by Author "Bump, Joseph K"

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    2021-2022 Greater Voyageurs Ecosystem wolf pack and population size report
    (2022) Gable, Thomas D; Homkes, Austin T; Bump, Joseph K
    This report presents and discusses data on wolf population metrics collected during 2021-2022 in the Greater Voyageur Ecosystem, Minnesota. In 2021-2022, we estimated the area of 9 wolf pack home ranges/territories, determined the size of 14 wolf packs, and obtained 7.3 independent observations of the same size for each pack. The survey effort in 2021-2022 was the same as 2020-2021 and represents the most intensive survey effort, in terms of number of packs and territories studied, to date in the Greater Voyageurs Ecosystem. We estimate that wolf population density in the Greater Voyageurs Ecosystem in 2021-2022 was 63.2 wolves/1000 km2 (95% confidence interval: 50.3-83.8 wolves/1000 km2). This density represents a 16% increase in population density from 2020-2021 and a 48% increase from the recent population low in 2019-2020 of 42.7 wolves/1000 km2. The increase in population density is largely attributable to increased pup survival, which likely increased pack size. We compared current wolf population density and population metrics to historical wolf density and population metrics in the Greater Voyageurs Ecosystem. This assessment suggests that wolf density in the GVE has changed little since the late 1980's, and that the GVE has sustained a high-density wolf population for decades.
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    2022-2023 Greater Voyageurs Ecosystem Wolf Population Report
    (2023) Gable, Thomas D; Homkes, Austin T; Bump, Joseph K
    During April 2022-April 2023, we studied the wolf population in the Greater Voyageurs Ecosystem (GVE), Minnesota in an effort to understand wolf population dynamics and how changes in population dynamics are connected to or influence predation behavior, wolf pup survival, and changes in prey density. We estimated the area of 8 wolf pack home ranges/territories and estimated the size of 20 wolf packs based on an average of 11.7 independent observations of each pack at the estimated size (i.e., the number of wolves we determined were in a given pack). In total, we recorded 606 observations of 2 or more wolves traveling together during the winter survey period. The 2022-2023 survey effort was the most intensive survey effort to date in the Greater Voyageurs Ecosystem, Minnesota. We estimate that wolf population density in the Greater Voyageurs Ecosystem in 2022-2023 was 65.2 wolves/1000 km^2 (95% confidence interval: 53.7-87.8 wolves/1000 km^2), indicating that wolf density remained unchanged from 2021-2022 (65.7 wolves/1000 km^2). Although wolf density has varied annually in the GVE since 2015, there is no indication that wolf density has increased or decreased with time. In other words, the population has remained relatively stable and current population density (65.2 wolves/1000 km^2) is close to the average population density (60.4 wolves/1000 km^2) over the past 9 years (2015-2023) in the GVE.
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    Code, data, and metadata document for the manuscript: Territorial landscapes: incorporating density-dependence into wolf resource selection study designs
    (2019-02-27) Bump, Joseph K; Beyer, Dean; O'Neil, Shawn; bump@umn.edu; Bump, Joseph K; Bump Lab at the University of Minnesota
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    Code, data, and metadata for the manuscript: Territoriality drives preemptive habitat selection in recovering wolves: implications for carnivore conservation
    (2020-03-09) O’Neil, Shawn T; Vucetich, John A; Beyer, Dean E; Hoy, Sarah R; Bump, Joseph K; bump@umn.edu; Bump, Joseph; Bump Lab
    1. According to the ideal-free distribution (IFD), individuals within a population are free to select habitats that maximize their chances of success. Assuming knowledge of habitat quality, the IFD predicts that average fitness will be approximately equal among individuals and between habitats, while density varies (density-dependent habitat selection). Populations are often assumed to follow an IFD, although this assumption is rarely tested with empirical data, and may be incorrect when territoriality indicates habitat selection tactics that deviate from the IFD (e.g. ideal despotic distribution or ideal preemptive distribution). 2. When territoriality influences habitat selection, species’ density will not directly reflect components of fitness such as reproductive success or survival. In such cases, assuming an IFD can lead to false conclusions about habitat quality. We tested theoretical models of density-dependent habitat selection on a species known to exhibit territorial behavior in order to determine whether commonly applied habitat models are appropriate under these circumstances. 3. We combined long-term radio telemetry and census data from gray wolves (Canis lupus) in the Upper Peninsula of Michigan, USA to relate spatiotemporal variability in wolf density to underlying classifications of habitat within a hierarchical state-space modeling framework. We then iteratively applied isodar analysis to evaluate which distribution of habitat selection best described this recolonizing wolf population. 4. The wolf population in our study expanded by >1000% during our study (~ 50 to > 600 individuals), and density-dependent habitat selection was most consistent with the ideal preemptive distribution, as opposed to the ideal-free or ideal-despotic alternatives. 5. Population density of terrestrial carnivores may not be positively correlated with the fitness value of their habitats, and density-dependent habitat selection patterns may help to explain complex predator-prey dynamics and cascading indirect effects. Source-sink population dynamics appear likely when species exhibit rapid growth and occupy interspersed habitats of contrasting quality. These conditions are likely and have implications for large carnivores in many systems, such as areas in North America and Europe where large predator species are currently recolonizing their former ranges.
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    Data for: Wolves alter the trajectory of forests by shaping the central-place foraging behavior of an ecosystem engineer
    (2023-04-12) Gable, Thomas D; Johnson-Bice, Sean M; Homkes, Austin T; Fieberg, John R; Bump, Joseph K; gable079@umn.edu; Gable, Thomas D; University of Minnesota Voyageurs Wolf Project
    Dataset for Gable et al. 2023 where the authors describe how wolves indirectly alter the trajectory of forests by constraining the distance that beavers, a central place forager and prolific ecosystem engineer, forage from water. Specifically, Gable et al. demonstrate wolves wait-in-ambush and kill beavers on longer feeding trails than would be expected based on the spatiotemporal availability of beavers. This pattern is driven by temporal dynamics of beaver foraging: beavers make more foraging trips and spend more time on land per trip on longer feeding trails that extend farther from water. As a result, beavers are more vulnerable on longer feeding trails than shorter ones. Wolf predation appears to be a selective evolutionary pressure propelled by consumptive and non-consumptive mechanisms that constrain the distance from water beavers forage, which in turn limits the area of forest around wetlands, lakes, and rivers beavers alter through foraging. Thus, wolves appear intricately linked to boreal forest dynamics by shaping beaver foraging behavior, a form of natural disturbance that alters the successional and ecological states of forests.
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    Observations of wolves eating berries in the Greater Voyageurs Ecosystem
    (2024-07-18) Evavold, Isabella; Gable, Thomas D; Homkes, Austin T; Bump, Joseph K; gable079@umn.edu; Gable, Thomas; University of Minnesota Voyageurs Wolf Project
    Wolves are opportunistic generalists that can respond quickly to new and unique food sources. Wolves in some ecosystems will consume berries and other fruits when they are abundant and available, however many aspects of this behavior remain unknown. In the Greater Voyageurs Ecosystem (GVE), Minnesota, USA, wolves consistently consume berries, particularly blueberries, when they are available. We deployed remote cameras in blueberry patches to record wolves foraging on berries over several years. We captured footage of wolves of all age-classes, social statuses, and sex foraging on blueberries alone or with other wolves. Our observations indicate berry consumption by wolves is a widespread behavior in the GVE and likely similar southern boreal ecosystems. We hope our work spurs researchers across wolf range to examine whether berry consumption by wolves is a widespread and ubiquitous behavior for wolves.
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    R code and data for "Comparing multiple survey and recruitment-mortality models to assess growth rates and population projections"
    (2019-09-23) Severud, William J; DelGiudice, Glenn D; Bump, Joseph K; seve0135@umn.edu; Severud, William J; Minnesota Department of Natural Resources Forest Wildlife Populations and Research Group
    This collection of files provides data and R code supporting the publication "Comparing survey and multiple recruitment-mortality models to assess growth rates and population projections" in Ecology and Evolution. We provide all necessary data not included in the manuscript to reproduce the analysis of growth rates and population projections of moose in northeastern Minnesota.
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    Single visits to active wolf dens do not impact wolf pup recruitment or pack size
    (2023-12-14) Gable, Thomas D; Johnson-Bice, Sean M; Homkes, Austin T; Bump, Joseph K; gable079@umn.edu; Gable, Thomas D; Voyageurs Wolf Project
    Dataset for Gable et al. where the authors used a quasi-experimental approach (reference vs. treatment) to determine whether visiting wolf dens and marking wolf (Canis lupus) pups affects important wolf population metrics. Specifically, Gable et al. examined whether pup recruitment and pack size differed between packs where they visited dens and handled pups (‘disturbed packs’ = treatment group) and those where they did not visit dens (‘undisturbed packs’ = reference group). During 2019-2023, they studied 43 wolf packs and litters, 19 of which were disturbed packs and 24 of which were undisturbed. They found no difference in recruitment or pack size between disturbed and undisturbed wolf packs. However, they did observe substantial annual variation in recruitment and pack size, which indicated that other ecological factors (e.g., prey abundance) were likely responsible for annual changes in recruitment and pack size. Their findings are consistent with several other studies, and together this research indicates that wolf dens can be visited once and wolf pups handled briefly for research purposes without having a measurable effect on recruitment and pack size.
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    Wolf predation on white-tailed deer before, during, and after a historically-mild winter in northern Minnesota
    (2024-11-15) Gable, Thomas D; Homkes, Austin T; Bump, Joseph K; gable079@umn.edu; Gable, Thomas D; Voyageurs Wolf Project
    See Read me file