Browsing by Subject "moose"

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    Assessing Calf Survival and the Quantitative Impact of Reproductive Success on the Declining Moose (Alces alces) Population in Northeastern Minnesota
    (2017-08) Severud, William
    Ungulate reproductive success is an important driver of population performance. Long-term, the northeastern Minnesota moose (Alces alces) population declined 58% since 2006, yet aerial survey estimates indicate stability during 2012–2017. Because causal mechanisms for this decline were largely unknown, I investigated calf production, survival and cause-specific mortality of calves of global positioning system (GPS)-collared dams of this population. Global positioning system collars have been deployed on adult moose and other ungulates to study various aspects of their ecology, but until the current study they had not been fitted to moose neonates. In 2013 and 2014, I GPS-collared 54 neonates and monitored them for survival. In 2015, I monitored 50 calving dams for signs of neonatal mortality using behavioral cues, and assessed seasonal calf survival with aerial surveys. In 2013 and 2014, collared calf survival to 9 months was 0.34 (95% CI = 0.23–0.52), whereas uncollared calf survival in 2015 was estimated at 0.40 (95% CI = 0.30–0.54). Survival in all 3 years dropped dramatically in the first 50 days of life; hazard peaked at about 15 days of age when dams and calves departed calving sites. Predation was the leading cause of death of collared calves (84% of mortalities); wolf (Canis lupus) predation accounted for 77% of deaths. The cumulative probability of succumbing to all forms of mortality by 9 months of age was 69.8%. I documented higher wolf predation than other recent studies with similar predator communities. Habitat use during calving and the energetically demanding post-parturition period can be an important determinant of neonatal survival. I surveyed and compared habitat characteristics of pre-calving, calving, peak-lactation, and mortality sites at a fine and broad scale. I also compared mortality sites of calves killed by wolves versus other causes, as well as calving sites of cows that successfully reared a calf to winter to those that did not. Cows tended to move to areas of more conifer forest cover to calve. During peak-lactation, cows and their calves used steeper areas with abundant forage, high concealment, and less conifer cover. Mortality sites were more level than other site types. Generally, wolf-kill sites were farther from roads. Cows that successfully reared a calf to winter typically calved in areas with more deciduous forest and less forested wetland cover than cows whose calves died. I estimated population growth rate (λ) using adult survival and calf recruitment data from the Minnesota Department of Natural Resources demographic studies and the Recruitment-Mortality (R-M) Equation, and compared this estimate to those calculated using data from the annual aerial survey. Measures of recruitment were similar whether derived from the survey or collaring studies, but generally were higher in the collared sample. More recent calculations of λ (derived from the survey [2012–2017 stabilization; 1.02 ± 0.16 (SE)] and using the R-M Equation [1.04 ± 0.04]) indicated growth over the next 50 years. However, the stochastic model using parameters from the adult and calf studies indicated an average decline in the population over the next 50 years (λ = 0.94 ± 0.004). Habitat improvement projects for moose should consider not only forage requirements, but also cover, slope, and road density. Identifying specific causes of calf mortality and understanding their relations to various landscape characteristics and other extrinsic factors should yield insight into mechanisms contributing to the declining moose population in northeastern Minnesota and serve as a basis for ecologically sound management responses.
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    Data, R Code, and Output Supporting "An Historical Overview and Update of Wolf-Moose Interactions in Northeastern Minnesota"
    (2017-10-06) Fieberg, John R; Mech, L. David; Barber-Meyer, Shannon; jfieberg@umn.edu; Fieberg, John R
    These files contain data and R code (along with associated output from running the code) supporting all results reported in, "Mech, L. D., J. Fieberg, and S. Barber-Meyer. In press. An historical overview and update of wolf-moose interactions in Northeastern Minnesota. Wildlife Society Bulletin." In this paper, we explored relationships between wolf numbers, monitored in part of the Minnesota moose range, and moose calf:population and estimated log annual growth rates of moose in Northeast Minnesota.
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    Genetic analysis of moose populations from Minnesota and Yellowstone National Park
    (2015-12) Tjepkes, Tessa
    By assessing the amount and geographic distribution of genetic variation in moose we can better understand how microevolutionary processes and landscape features have influenced that variation. How the distribution of moose changes in the future will be partially dictated by the amount and content of genetic variation moose populations possess. Therefore, it will be useful to acquire more moose population genetic data and to study declining populations. My thesis had two primary objectives: (1) to compare the efficacy of DNA extraction from different biological samples and (2) to genotype a subset of Minnesota moose at a locus known to be associated with chronic wasting disease in other cervid populations. DNA for genetic analyses was extracted from blood, tissue, and pellets. Extracted DNA from all source types was sufficient for genotyping using 15 microsatellites and Sanger sequencing. However, DNA extracted from pellets was of both lower quality and quantity than DNA extracted from blood and tissue. Minnesota moose contain polymorphisms that have been correlated with increased susceptibility to chronic wasting disease in cervids in other areas. These results provide valuable comparisons of efficiency and effectiveness of DNA extraction protocols for tissue, blood, and fecal pellets as well as baseline population genetic data that can be used to detect future genetic changes in these populations.
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    Growth Rates and Variances of Unexploited Wolf Populations in Dynamic Equilibria: Data, R Code, and Supporting Results
    (2014-07-18) Fieberg, John R; Mech, David; jfieberg@umn.edu; Fieberg, John R
    These files contain data and R code (along with associated output from running the code) supporting all results reported in: Mech, D. and J. Fieberg. 2014. Growth Rates and Variances of Unexploited Wolf Populations in Dynamic Equilibria. Wildlife Society Bulletin. In Mech and Fieberg (2014), we analyzed natural, long-term, wolf-population-density trajectories totaling 130 years of data from three areas: Isle Royale National Park in Lake Superior, Michigan; the east-central Superior National Forest in northeastern Minnesota; and Denali National Park, Alaska. We fit density-independent and Ricker models to each time series, allowing for 3 different assumptions regarding observation error (no error, Poisson or Log-normal observation error). We suggest estimates of the population-dynamic parameters can serve as benchmarks for comparison with those calculated from other wolf populations repopulating other areas.
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    Python and R codes for "Exploring the role of parental proximity in the maternal-neonate bond and parental investment in moose (Alces alces) through post-capture movement dynamics"
    (2020-10-28) DelGiudice, Glenn; Ahmadkhani, Mohsen; St-Louis, Veronique; Severud, William; Obermoller, Tyler; glenn.delgiudice@state.mn.us; DelGiudice, Glenn; Minnesota Department of Natural Resources Forest Wildlife Populations and Research Group
    The submitted python script performs moose movement analyses (i.e dynamic interaction (DI) values, and reunion analysis). The R script measures MCP and KDE home range values for the animals.
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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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    R code and output supporting: Time series sightability modeling of animal populations
    (2017-03-29) ArchMiller, Althea A; Fieberg, John R; Dorazio, Robert M; St. Clair, Katherine; althea.archmiller@gmail.com; ArchMiller, Althea A
    The goal of our study was to expand a previously developed model-based approach to include random effects and a temporal spline for time series modeling of multiple years of operational survey data. We developed a Bayesian hierarchical model as our framework to build and compare fixed-effects and temporal model-based sightability models applied to 12 years of MN moose operational survey data. Here, we share the Program R code and data necessary to replicate the manuscript results that demonstrate how our time series sightability modeling approach can increase the precision of population estimators and predict population dynamics with smoother (and thus more realistic trends) through time.
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    Seasonal Diet Composition of Gray Wolves (Canis lupus) in Northeastern Minnesota Determined by Scat Analysis
    (2015-08) Chenaux-Ibrahim, Yvette
    I determined seasonal diet composition of gray wolves (Canis lupus) in northeastern Minnesota from 2011 to 2013. Average occurrence of prey items was identified in 1,000 scats collected in the Grand Portage Indian Reservation, Voyageurs National Park area, and the 1854 Ceded Territory (greater northeastern Minnesota). Deer (Odocoileus virginianus), moose (Alces alces), and beaver (Castor canadensis) composed the majority of wolf diet, with moose the primary prey in Grand Portage and deer the primary prey in the Ceded Territory and Voyageurs National Park. Beaver were important in spring and summer in Grand Portage and Voyageurs National Park. I performed a sensitivity analysis of expected densities of deer, moose, and beaver to calculate prey preference and determined that at most prey densities, moose were preferred and deer avoided in Grand Portage and the Ceded Territory and beaver were preferred in Voyageurs National Park. Small mammals, black bear (Ursus americanus), snowshoe hare (Lepus americanus), and canids composed a minor portion of wolf diet. Calves were important prey in spring in the Ceded Territory and fawns were important prey in spring and summer in Grand Portage and in summer in Voyageurs National Park. I estimated that wolves consumed about 30% of calves born each year in Grand Portage. I performed a sensitivity analysis to test how selecting 3, 6, 12, and 25 hairs per scat affects accuracy in determining diet composition. Prey items were occasionally missed when selecting fewer hairs, thus I recommend selecting 12 hairs per scat when using the point-frame method to determine wolf diet.
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    SPATIAL AND TEMPORAL ABUNDANCE OF GASTROPOD INTERMEDIATE HOSTS IN NORTHEASTERN MINNESOTA WITH IMPLICATIONS FOR PARELAPHOSTRONGYLUS TENUIS RISK IN MOOSE
    (2015-04) Cyr, Tim
    Parelaphostrongylus tenuis is a nematode meningeal parasite that requires white-tailed deer primary hosts and terrestrial gastropod intermediate hosts to complete its life cycle. While white-tailed deer are the only host in which P. tenuis can complete its life cycle, P. tenuis can be lethal to moose and other cervids that accidentally ingest infected gastropods while browsing. Describing the spatial and temporal changes in gastropod abundance will increase understanding about the risk of P. tenuis infection by moose at the individual and population levels. We used cardboard traps and hand searches to estimate terrestrial gastropod species composition and abundance in representative vegetation communities in Northeastern Minnesota. We also tested the gastropods for P. tenuis infection. We also measured various environmental factors that may explain terrestrial gastropod distribution. Gastropods were most abundant in conifer and regenerating forests (11.2/m2) while mixed forests had the lowest gastropod abundance (7.0/m2). Gastropods were more abundant in September than June and July and none were collected in November. Seventy four gastropods were found climbing on vegetation up to three meters off the ground. 0.1% of the identified gastropods were infected with P. tenuis. Spatial and temporal changes in gastropod abundance could provide different risk levels of P. tenuis infection for moose. Our research will help to evaluate infection risk in the most common moose habitats in Northeastern Minnesota.
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    Using Movement Behavior Of Adult Female Moose To Estimate Survival And Cause-Specific Mortality Of Calves In A Declining Population
    (2017-09) Obermoller, Tyler
    Low calf production and survival can contribute to ungulate population declines and sustained low numbers. Continuing research on cause-specific mortality and annual survival of moose (Alces alces) calves in northeastern Minnesota is critical to understanding the long-term trajectory of the population. Beginning in late April 2016, 35 global positioning system (GPS)-collared adult females were computer-monitored for calving movements, a long distance movement followed by an intense localization. I observed 28 of 33 (85%) females make a calving movement, and with additional field observations of calves, determined 31 of the 35 (89%) females were pregnant. Mean birth-date was 12 May 2016 (median = 11 May 2016, range = 24 Apr ̶ 10 June. In 2013–2014, I observed an unusual behavior by dams, a “mortality movement,” associated with the death of their neonate. The dam made a rapid, long-distance movement (“flee”), followed by a return to the calf mortality site. In 2016, using this behavior as a calf mortality indicator, I documented evidence of 15 mortalities at a mean age of 30.6 days (± 15.5 [SE], range = 3–243 days). Based on observations of mortality movements, 21 investigations were launched and resulted in confirmation of 11 of the 15 calf mortalities. Specific causes of mortality included 9 wolf (Canis lupus)-kills, 3 black bear (Ursus americanus)-kills, 1 unknown predator-kill, and 2 deaths following vehicle collisions. Predation accounted for 87% of all mortalities. The cumulative probability of calves being killed by wolves and bears was 33% and 11%, respectively. The mean distance dams fled after a mortality was 1,873 m (± 412, range = 126–5,805 m, n = 14). Dams that made return visits returned a mean 2.8 times (± 0.5, range = 1–5, n = 8) to the mortality site. Dams returned to within a mean 106 m (± 22, range = 34–230 m, n = 8) from the mortality site. Calf survival to 30 days of age was 67% (± 8, 95% CI = 53–84%, n = 36). Survival declined to 33% (± 8, CI = 20–53%, n = 36) at almost 1 year of age, associated with an estimated calf:cow ratio of 0.35. I developed 2 population-level movement models to improve efficacy of the mortality movement for identifying calf mortalities during the first summer of life. The first approach, a temporal-based model, used a single, estimated movement velocity threshold (164 m/hr) for the dam to indicate calf mortality and accurately predicted survival status 51% of the time. My second approach, an age-specific model, using different thresholds (28–135 m/hr) for the dam relative to calf age, was 80% accurate. Using movement behavior of dams to assess calf mortality can yield important insights into mechanisms related to the decline of the population in northeastern Minnesota and aid in future management decisions.