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At least 73 records · Page 4Linked to original sources

USGS2025

Parasite‐mediated competition limits dominant cervid competitor

Species interactions structure ecological communities through direct and indirect pathways with ecosystem-wide implications. Despite mounting interest in the importance of indirect interactions, empirical evidence remains limited. Here, we demonstrate the critical role of parasite-mediated competition in driving community outcomes in a multi-species system of conservation and management concern. We leveraged 2 years of detection/non-detection data of moose ( Alces alces ) and white-tailed deer ( Odocoileus virginianus ) and parasite loads in faecal samples within a hierarchical abundance-mediated interaction model to test hypotheses regarding interactions between these cervids and their shared parasites ( Parelaphostrongylus tenuis , Fascioloides magna ). We demonstrate that moose occupancy was limited by parasite-mediated competition, with no evidence of population-level effects of direct competitive interactions between moose and white-tailed deer. Such evidence of the importance of indirect interactions and resulting community outcomes is critical for species conservation and managing range contractions due to increasing pressures from habitat loss, disease and climate change.

New York↗

USGS2016

Differential wolf-pack-size persistence and the role of risk when hunting dangerous prey

Risk to predators hunting dangerous prey is an emerging area of research and could account for possible persistent differences in gray wolf ( Canis lupus ) pack sizes. We documented significant differences in long-term wolf-pack-size averages and variation in the Superior National Forest (SNF), Denali National Park and Preserve, Yellowstone National Park, and Yukon, Canada (p<0.01). The SNF differences could be related to the wolves’ risk when hunting primary prey, for those packs (N=3) hunting moose ( Alces americanus ) were significantly larger than those (N=10) hunting white-tailed deer ( Odocoileus virginianus ) (F1,8=16.50, p=0.004). Our data support the hypothesis that differential pack-size persistence may be perpetuated by differences in primary prey riskiness to wolves, and we highlight two important extensions of this idea: (1) the potential for wolves to provision and defend injured packmates from other wolves and (2) the importance of less-risky, buffer prey to pack-size persistence and year-to-year variation. Risk to predators hunting dangerous prey is an emerging area of research and could account for possible persistent differences in gray wolf ( Canis lupus ) pack sizes. We documented significant differences in long-term wolf-pack-size averages and variation in the Superior National Forest (SNF), Denali National Park and Preserve, Yellowstone National Park, and Yukon, Canada (p<0.01). The SNF differences could be related to the wolves’ risk when hunting primary prey, for those packs (N=3) hunting moose ( Alces americanus ) were significantly larger than those (N=10) hunting white-tailed deer ( Odocoileus virginianus ) (F1,8=16.50, p=0.004). Our data support the hypothesis that differential pack-size persistence may be perpetuated by differences in primary prey riskiness to wolves, and we highlight two important extensions of this idea: (1) the potential for wolves to provision and defend injured packmates from other wolves and (2) the importance of less-risky, buffer prey to pack-size persistence and year-to-year variation.

Behaviour↗

USGS2018

A novel technique for isolating DNA from Tempus™ blood RNA tubes after RNA isolation

Objective We use Tempus blood RNA tubes (Applied Biosystems) during health assessments of American moose ( Alces alces spp.) as a minimally invasive means to obtain RNA. Here we describe a novel protocol to additionally isolate high-quality DNA from the supernatant remaining after the RNA isolation methodology. Metrics used to qualify DNA quality included measuring the concentration, obtaining a DNA integrity number from a genomic DNA ScreenTape assay (Agilent), and running the isolated DNA on an agarose gel. Results Of the 23 samples analyzed, the average DNA concentration was 121 ng/µl (range 4–337 ng/µl) and a genomic DNA ScreenTape assay of seven samples indicated high DNA integrity values for 6 of the 7 samples (range 9.1–9.4 out of 10). Of the DNA sent for genotyping by sequencing, all proved to be of sufficient integrity to yield high-quality next-generation sequence results. We recommend this simple procedure to maximize the yield of both RNA and DNA from blood samples.

BMC Research Notes↗

USGS2017

Endemic chronic wasting disease causes mule deer population decline in Wyoming

Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy affecting white-tailed deer ( Odocoileus virginianus ), mule deer ( Odocoileus hemionus ), Rocky Mountain elk ( Cervus elaphus nelsoni ), and moose ( Alces alces shirasi) in North America. In southeastern Wyoming average annual CWD prevalence in mule deer exceeds 20% and appears to contribute to regional population declines. We determined the effect of CWD on mule deer demography using age-specific, female-only, CWD transition matrix models to estimate the population growth rate ( λ ). Mule deer were captured from 2010–2014 in southern Converse County Wyoming, USA. Captured adult (≥ 1.5 years old) deer were tested ante-mortem for CWD using tonsil biopsies and monitored using radio telemetry. Mean annual survival rates of CWD-negative and CWD-positive deer were 0.76 and 0.32, respectively. Pregnancy and fawn recruitment were not observed to be influenced by CWD. We estimated λ = 0.79, indicating an annual population decline of 21% under current CWD prevalence levels. A model derived from the demography of only CWD-negative individuals yielded; λ = 1.00, indicating a stable population if CWD were absent. These findings support CWD as a significant contributor to mule deer population decline. Chronic wasting disease is difficult or impossible to eradicate with current tools, given significant environmental contamination, and at present our best recommendation for control of this disease is to minimize spread to new areas and naïve cervid populations.

Wyoming↗

USGS2018

Time series sightability modeling of animal populations

Logistic regression models—or “sightability models”—fit to detection/non-detection data from marked individuals are often used to adjust for visibility bias in later detection-only surveys, with population abundance estimated using a modified Horvitz-Thompson (mHT) estimator. More recently, a model-based alternative for analyzing combined detection/non-detection and detection-only data was developed. This approach seemed promising, since it resulted in similar estimates as the mHT when applied to data from moose ( Alces alces ) surveys in Minnesota. More importantly, it provided a framework for developing flexible models for analyzing multiyear detection-only survey data in combination with detection/non-detection data. During initial attempts to extend the model-based approach to multiple years of detection-only data, we found that estimates of detection probabilities and population abundance were sensitive to the amount of detection-only data included in the combined (detection/non-detection and detection-only) analysis. Subsequently, we developed a robust hierarchical modeling approach where sightability model parameters are informed only by the detection/non-detection data, and we used this approach to fit a fixed-effects model (FE model) with year-specific parameters and a temporally-smoothed model (TS model) that shares information across years via random effects and a temporal spline. The abundance estimates from the TS model were more precise, with decreased interannual variability relative to the FE model and mHT abundance estimates, illustrating the potential benefits from model-based approaches that allow information to be shared across years.

PLoS ONE↗

USGS2001

Moose, caribou, and grizzly bear distribution in relation to road traffic in Denali National Park, Alaska

Park managers are concerned that moose ( Alces alces ), caribou ( Rangifer tarandus ), and grizzly bears ( Ursus arctos ) may be avoiding areas along the 130 km road through Denali National Park as a result of high traffic volume, thus decreasing opportunities for visitors to view wildlife. A wildlife monitoring system was developed in 1996 that used 19 landscape level view sheds, stratified into four sections based on decreasing traffic along the road corridor. Data were collected from 22 samplings of all viewsheds during May-August in 1996 and 1997. In 1997, nine backcountry viewsheds were established in three different areas to determine whether density estimates for each species in the backcountry were higher than those for the same animals in similar road-corridor areas. Densities higher than those in the road corridor were found in one backcountry area for moose and in two backcountry areas for grizzly bears. None of the backcountry areas showed a higher density of caribou. We tested hypotheses that moose, caribou, and grizzly bear distributions were unrelated to the road and traffic. Moose sightings were lower than expected within 300 m of the road. More caribou and grizzly bears than expected occurred between 601 and 900 m from the road, while more moose and fewer caribou than expected occurred between 900 and 1200 m from the road. Bull moose in stratum 1 were distributed farther from the road than bulls and cows in stratum 4; cows in stratum 1 and bul1s in stratum 2 were distributed farther from the road than cows in stratum 4. Grizzly bears in stratum 2 were distributed farther from the road than bears in stratum 3. The distribution of moose sightings suggests traffic avoidance, but the spatial pattern of preferred forage may have had more of an influence. Caribou and grizzly bear distributions indicated no pattern of traffic avoidance.

Alaska↗

USGS2006

A 3-decade dearth of deer (Odocoileus virginianus) in a wolf (Canis lupus)-dominated ecosystem

Some 30 y after wolves ( Canis lupus ) were implicated in decimating wintering white-tailed deer ( Odocoileus virginianus ) in a 3000-km 2 area of northeastern Minnesota, wintering deer still have not recolonized the area. From 1976 to 2004, we aerially radio-tracked wolves there during 250 h and recorded 2 deer (in 1985 and 2000) killed or eaten by wolves during February and March. We observed no other deer or deer sign, but regularly observed deer, deer sign and wolf-killed deer in adjacent wolf-pack territories. Although habitat in the study area generally remains poor, some regeneration has taken place, and deer have increased adjacent to the area. However, wolf numbers have persisted by preying on moose ( Alces alces ). We could detect no reason other than wolf predation and deer migration traditions for why wintering deer have not recolonized the area.

Minnesota↗

USGS2007

Deer exposed to exceptionally high concentrations of lead near the Continental Mine in Idaho, USA

Habitat surrounding the inactive Continental Mine in northern Idaho, USA, supports bear ( Ursus arctos, Ursus americanus ), moose ( Alces alces ), elk ( Cervus elaphus ), woodland caribou ( Rangifer tarandus caribou ), and abundant mule ( Odocoileus hemionus ) and white-tailed deer ( Odocoileus virginianus ). Tailings on the mining site were capped and remediated in 2003 to reduce environmental exposure of surrounding soil and sediments of Blue Joe Creek, downslope of the mine. Before capping, the mean Pb concentration in deer pellets collected on-site was 920 mg/kg of Pb (dry wt). This exposure, if chronic, would be comparable to an exposure that could be lethal to cattle or horses. Surprisingly, the mean pellet Pb concentration of 950 mg/kg in 2004 was as high as it was before remediation, and it was related to a high rate of soil ingestion. Mean soil content of the pellets collected from the capped site in 2004 was 22% dry weight, estimated from the acid-insoluble ash, a marker of soil ingestion. Clumps of sand and bits of rock were observed inside some of the pellets, and Pb concentrations in the pellets were correlated (p < 0.05) with soil content. Although terrestrial risk assessments generally estimate exposure from diets and from incidentally ingested soil, the deer at this site were directly ingesting contaminated soil or mining waste. The mean Pb concentration of this ingested soil was estimated as 6,700 mg/kg and the maximum as 25,000 mg/kg, well above the Pb concentrations measured in the remediated cap. The deer seemed to be ingesting soil or mining waste from one or more small but highly contaminated sources located beyond the remediated cap.

Idaho↗

USGS2006

Pathogens, nutritional deficiency, and climate influences on a declining moose population

Several potential proximate causes may be implicated in a recent (post-1984) decline in moose ( Alces alces andersoni ) numbers at their southern range periphery in northwest Minnesota, USA. These causes include deleterious effects of infectious pathogens, some of which are associated with white-tailed deer ( Odocoileus virginianus ), negative effects of climate change, increased food competition with deer or moose, legal or illegal hunting, and increased predation by gray wolves ( Canis lupus ) and black bears ( Ursus americanus ). Long-standing factors that may have contributed to the moose decline include those typically associated with marginal habitat such as nutritional deficiencies. We examined survival and productivity among radiocollared ( n = 152) adult female and juvenile moose in northwest Minnesota during 1995–2000, and assessed cause of death and pathology through carcass necropsy of radiocollared and non-radiocollared animals. Aerial moose surveys suggested that hunting was an unlikely source of the numerical decline because the level of harvest was relatively low (i.e., approx. 15% / 2 yr) and the population usually grew in years following a hunt. The majority of moose mortalities (up to 87% of radiocollared moose [ n = 76] and up to 65% of non-radiocollared moose [ n = 84]) were proximally related to pathology associated with parasites and infectious disease. Liver fluke ( Fascioloides magna ) infections apparently constituted the greatest single source of mortality and caused significant pathology in the liver, thoracic and peritoneal cavities, pericardial sac, and lungs. Mortality due to meningeal worm ( Parelaphostrongylus tenuis ) was less prevalent and was manifested through characteristic neurological disease. Several mortalities apparently were associated with unidentified infectious disease, probably acting in close association with malnutrition. Bone-marrow fat was lower for moose dying of natural causes than those dying of anthropogenic factors or accidents, implying that acute malnutrition contributed to moose mortality. Blood profiles from live-captured animals indicated that those dying in the subsequent 18 months were chronically malnourished. Relative to other populations, average annual survival rates for adult females (0.79 [0.74–0.84; 95% CI]) and yearlings (0.64 [0.48–0.86]) were low, whereas those for calves (0.66 [0.53–081]) were high. Pregnancy (48%) and twinning (19%) rates were among the lowest reported for moose, with reproductive senescence among females being apparent as early as 8 years. Pregnancy status was related to indices of acute (i.e., bone-marrow fat) and chronic (i.e., blood condition indices) malnutrition. Opportunistic carcass recovery indicated that there likely were few prime-aged males (>5 yr old) in the population. Analysis of protein content in moose browse and fecal samples indicated that food quality was probably adequate to support moose over winter, but the higher fecal protein among animals that died in the subsequent 18 months could be indicative of protein catabolism associated with malnutrition. Trace element analysis from moose livers revealed apparent deficiencies in copper and selenium, but there was limited evidence of direct association between trace element concentrations and moose disease, pathology, or mortality. Time-series analysis of regional moose counts (1961–2000) indicated that annual population growth rate was related negatively to mean summer temperature, with winter and summer temperatures increasing by an average of 6.8 and 2.1 C, respectively, during the 40-year period. This change may have increased moose thermoregulatory costs and disrupted their energy balance, and thereby reduced their fitness. Time-series analysis failed to show a relationship between annual population growth rate and moose or deer abundance, indicating that food limitation via resource competition was unlikely. Population viability analyses, using count data (1961–2000) and demographic data collected during this study, suggested that the northwest Minnesota moose population likely would not persist over the next 50 years. More broadly, we conclude that the southern distribution of moose may become restricted in areas where climate and habitat conditions are marginal, especially where deer are abundant and act as reservoir hosts for parasites.

Minnesota↗

USGS2010

Ranking Alaska moose nutrition: Signals to begin liberal antlerless harvests

We focused on describing low nutritional status in an increasing moose ( Alces alces gigas ) population with reduced predation in Game Management Unit (GMU) 20A near Fairbanks, Alaska, USA. A skeptical public disallowed liberal antlerless harvests of this moose population until we provided convincing data on low nutritional status. We ranked nutritional status in 15 Alaska moose populations (in boreal forests and coastal tundra) based on multiyear twinning rates. Data on age-of-first-reproduction and parturition rates provided a ranking consistent with twinning rates in the 6 areas where comparative data were available. Also, short-yearling mass provided a ranking consistent with twinning rates in 5 of the 6 areas where data were available. Data from 5 areas implied an inverse relationship between twinning rate and browse removal rate. Only in GMU 20A did nutritional indices reach low levels where justification for halting population growth was apparent, which supports prior findings that nutrition is a minor factor limiting most Alaska moose populations compared to predation. With predator reductions, the GMU 20A moose population increased from 1976 until liberal antlerless harvests in 2004. During 1997–2005, GMU 20A moose exhibited the lowest nutritional status reported to date for wild, noninsular, North American populations, including 1) delayed reproduction until moose reached 36 months of age and the lowest parturition rate among 36-month-old moose (29%, n = 147); 2) the lowest average multiyear twinning rates from late-May aerial surveys ( x̄ = 7%, SE = 0.9%, n = 9 yr, range = 3–10%) and delayed twinning until moose reached 60 months of age; 3) the lowest average mass of female short-yearlings in Alaska ( x̄ = 155 ± 1.6 [SE] kg in the Tanana Flats subpopulation, up to 58 kg below average masses found elsewhere); and 4) high removal (42%) of current annual browse biomass compared to 9–26% elsewhere in boreal forests. When average multiyear twinning rates in GMU 20A (sampled during 1960–2005) declined to <10% in the mid- to late 1990s, we began encouraging liberal antlerless harvests, but only conservative annual harvests of 61–76 antlerless moose were achieved during 1996–2001. Using data in the context of our broader ranking system, we convinced skeptical citizen advisory committees to allow liberal antlerless harvests of 600–690 moose in 2004 and 2005, with the objective of halting population growth of the 16,000–17,000 moose; total harvests were 7–8% of total prehunt numbers. The resulting liberal antlerless harvests served to protect the moose population's health and habitat and to fulfill a mandate for elevated yield. Liberal antlerless harvests appear justified to halt population growth when multiyear twinning rates average ≤10% and ≥1 of the following signals substantiate low nutritional status: <50% of 36-month-old moose are parturient, average multiyear short-yearling mass is <175 kg, or >35% of annual browse biomass is removed by moose.

Journal of Wildlife Management↗

USGS2010

Temperature mediated moose survival in Northeastern Minnesota

The earth is in the midst of a pronounced warming trend and temperatures in Minnesota, USA, as elsewhere, are projected to increase. Northern Minnesota represents the southern edge to the circumpolar distribution of moose (Alces alces), a species intolerant of heat. Moose increase their metabolic rate to regulate their core body temperature as temperatures rise. We hypothesized that moose survival rates would be a function of the frequency and magnitude that ambient temperatures exceeded the upper critical temperature of moose. We compared annual and seasonal moose survival in northeastern Minnesota between 2002 and 2008 with a temperature metric. We found that models based on January temperatures above the critical threshold were inversely correlated with subsequent survival and explained >78 of variability in spring, fall, and annual survival. Models based on late-spring temperatures also explained a high proportion of survival during the subsequent fall. A model based on warm-season temperatures was important in explaining survival during the subsequent winter. Our analyses suggest that temperatures may have a cumulative influence on survival. We expect that continuation or acceleration of current climate trends will result in decreased survival, a decrease in moose density, and ultimately, a retreat of moose northward from their current distribution.

Journal of Wildlife Management↗

USGS2010

Revisions of rump fat and body scoring indices for deer, elk, and moose

Because they do not require sacrificing animals, body condition scores (BCS), thickness of rump fat (MAXFAT), and other similar predictors of body fat have advanced estimating nutritional condition of ungulates and their use has proliferated in North America in the last decade. However, initial testing of these predictors was too limited to assess their reliability among diverse habitats, ecotypes, subspecies, and populations across the continent. With data collected from mule deer ( Odocoileus hemionus ), elk ( Cervus elaphus ), and moose ( Alces alces ) during initial model development and data collected subsequently from free-ranging mule deer and elk herds across much of the western United States, we evaluated reliability across a broader range of conditions than were initially available. First, to more rigorously test reliability of the MAXFAT index, we evaluated its robustness across the 3 species, using an allometric scaling function to adjust for differences in animal size. We then evaluated MAXFAT, rump body condition score (rBCS), rLIVINDEX (an arithmetic combination of MAXFAT and rBCS), and our new allometrically scaled rump-fat thickness index using data from 815 free-ranging female Roosevelt and Rocky Mountain elk ( C. e. roosevelti and C. e. nelsoni ) from 19 populations encompassing 4 geographic regions and 250 free-ranging female mule deer from 7 populations and 2 regions. We tested for effects of subspecies, geographic region, and captive versus free-ranging existence. Rump-fat thickness, when scaled allometrically with body mass, was related to ingesta-free body fat over a 38–522-kg range of body mass ( r 2 = 0.87; P < 0.001), indicating the technique is remarkably robust among at least the 3 cervid species of our analysis. However, we found an underscoring bias with the rBCS for elk that had >12% body fat. This bias translated into a difference between subspecies, because Rocky Mountain elk tended to be fatter than Roosevelt elk in our sample. Effects of observer error with the rBCS also existed for mule deer with moderate to high levels of body fat, and deer body size significantly affected accuracy of the MAXFAT predictor. Our analyses confirm robustness of the rump-fat index for these 3 species but highlight the potential for bias due to differences in body size and to observer error with BCS scoring. We present alternative LIVINDEX equations where potential bias from rBCS and bias due to body size are eliminated or reduced. These modifications improve the accuracy of estimating body fat for projects intended to monitor nutritional status of herds or to evaluate nutrition's influence on population demographics.

Journal of Wildlife Diseases↗

USGS1985

Observation of a wolf killed by a deer

Wolves (Canis lupus ) probably risk injury while attempting to kill large prey (Muie, 1944; Rausch, 1967; Mech, 1970; Peterson, 1977). Rausch (1967) found that numerous wolf skulls collected in a control program had sustained injuries, probably inflicted by severe blows from moose (Alces alces ). Wolves killed by prey seldom if ever are found. The authors located only three such published records, two involving moose (MacFarlane, 1905; Stanwell-Fletcher and Stanwell-Fletcher, 1942), and one involving deer (Odocoileus virginianus ) (Frijlink, 1977). In the latter case, the wolf was rabid and apparently was killed by a blow to the head, presumably by a hoof.

Journal of Mammalogy↗

USGS1992

Intraspecific mitochondrial DNA variation in North American cervids

Intraspecific variation in mitochondrial DNA of North American cervids was assessed with restriction enzymes to determine relationships among populations and subspecies. No variation was detected in moose ( Alces alces ) and little in elk ( Cervus elaphus ). Caribou ( Rangifer tarandus ), white-tailed deer ( Odocoileus virginianus ), and mule deer ( Odocoileus hemionus ) possessed considerable variation. Characteristic genotypes exist in caribou and white-tailed deer from different geographic areas although subspecies are not discernable as distinct mtDNA assemblages. Except for O. hemionus , intraspecific mtDNA sequence divergences are small (<2%). Subspecies of mule deer have divergent mtDNA (7%) and are the only subspecies of cervids with distinct genotypes.

Journal of Mammalogy↗

USGS1999

Life-history strategies of ungulates

This Special Feature resulted from a symposium on life-history strategies of ungulates presented at the 78th Annual Meeting of the American Society of Mammalogists in Blacks-burg, Virginia, in June 1998. The presentations at the symposium represented only a vignette of the wide variety of life-history strategies that exists among ungulates. The four papers that follow include treatises on birth-site selection of moose ( Alces alces ), sex-ratio correlates with dimorphism and risk of predation, optimal foraging relative to risk of predation, and the role of density dependence in shaping life-history traits of ungulates. A theme of risk of predation in shaping life-history traits is common to three of four papers.

Journal of Mammalogy↗

USGS1979

An improved method of censusing deer in deciduous-coniferous forests

Aerial censusing has been used to determine densities of many large mammals, including deer ( Odocoileus virginianus ) in agricultural areas or deciduous forests (Saugstad 1942, Morse 1946, Petrides 1953, Sanderson 1953, Berner pers. comm.). However, observability of deer from the air remains a problem in northern coniferous forests. LeResche and Rausch (1974) determined that even with the much larger and more observable moose ( Alces alces ) during ideal snow conditions, experienced observers counted only 68% of a known number of animals; inexperienced observers counted 43%. Caughley (1974) and Caughley et al. (1976) suggested that the best solution to the problem of observability in aerial censuses is to measure the magnitude of the biases that exist, and correct estimates accordingly. This paper describes an attempt to measure observability bias in an aerial census of deer in deciduous coniferous habitat and to produce an accurate estimate of numbers.

Minnesota↗

USGS1987

Relationship of deer and moose populations to previous winters' snow

(1) Linear regression was used to relate snow accumulation during single and consecutive winters with white-tailed deer ( Odocoileus virginianus ) fawn:doe ratios, moose ( Alces alces ) twinning rates and calf:cow ratios, and annual changes in deer and moose populations. Significant relationships were found between snow accumulation during individual winters and these dependent variables during the following year. However, the strongest relationships were between the dependent variables and the sums of the snow accumulations over the previous three winters. The percentage of the variability explained was 36 to 51. (2) Significant relationships were also found between winter vulnerability of moose calves and the sum of the snow accumulations in the current, and up to seven previous, winters, with about 49% of the variability explained. (3) No relationship was found between wolf numbers and the above dependent variables. (4) These relationships imply that winter influences on maternal nutrition can accumulate for several years and that this cumulative effect strongly determines fecundity and/or calf and fawn survivability. Although wolf ( Canis lupus L.) predation is the main direct mortality agent on fawns and calves, wolf density itself appears to be secondary to winter weather in influencing the deer and moose populations.

Journal of Animal Ecology↗

USGS1995

The cumulative effect of consecutive winters' snow depth on moose and deer populations: a defence

1. L. D. Mech et al. presented evidence that moose Alces alces and deer Odocoileus virginianus population parameters re influenced by a cumulative effect of three winters' snow depth. They postulated that snow depth affects adult ungulates cumulatively from winter to winter and results in measurable offspring effects after the third winter. 2. F. Messier challenged those findings and claimed that the population parameters studied were instead affected by ungulate density and wolf indexes. 3. This paper refutes Messier's claims by demonstrating that his results were an artifact of two methodological errors. The first was that, in his main analyses, Messier used only the first previous winter's snow depth rather than the sum of the previous three winters' snow depth, which was the primary point of Mech et al. Secondly, Messier smoothed the ungulate population data, which removed 22-51% of the variability from the raw data. 4. When we repeated Messier's analyses on the raw data and using the sum of the previous three winter's snow depth, his findings did not hold up.

Journal of Animal Ecology↗