Factors affecting gray wolf (Canis lupus) encounter rate with elk (Cervus elaphus) in Yellowstone National Park

2018 ◽  
Vol 96 (9) ◽  
pp. 1032-1042 ◽  
Author(s):  
H.W. Martin ◽  
L.D. Mech ◽  
J. Fieberg ◽  
M.C. Metz ◽  
D.R. MacNulty ◽  
...  
Keyword(s):  
Cervus Elaphus ◽  
Canis Lupus ◽  
Yellowstone National Park ◽  
Snow Depth ◽  
National Park ◽  
Encounter Rate ◽  
Encounter Rates ◽  
Hunting Success ◽  
Kill Rate ◽  
The Relationship

Despite encounter rates being a key component of kill rate, few studies of large carnivore predation have quantified encounter rates with prey, the factors that influence them, and the relationship between encounter rate and kill rate. The study’s primary motivation was to determine the relationship between prey density and encounter rate in understanding the mechanism behind the functional response. Elk (Cervus elaphus Linnaeus, 1758) population decline and variable weather in northern Yellowstone National Park provided an opportunity to examine how these factors influenced wolf (Canis lupus Linnaeus, 1758) encounter rates with elk. We explored how factors associated with wolf kill rate and encounter rate in other systems (season, elk density, elk group density, average elk group size, snow depth, wolf pack size, and territory size) influenced wolf–elk encounter rate in Yellowstone National Park. Elk density was the only factor significantly correlated with wolf–elk encounter rate, and we found a nonlinear density-dependent relationship that may be a mechanism for a functional response in this system. Encounter rate was correlated with number of elk killed during early winter but not late winter. Weak effects of snow depth and elk group size on encounter rate suggest that these factors influence kill rate via hunting success because kill rate is the product of hunting success and encounter rate.

scholarly journals Unusual Behavior by Bison, Bison bison, Toward Elk, Cervus elaphus, and Wolves, Canis lupus

2004 ◽  
Vol 118 (1) ◽  
pp. 115 ◽  
Author(s):  
L. David Mech ◽  
Rick T. McIntyre ◽  
Douglas W. Smith
Keyword(s):  
Cervus Elaphus ◽  
Canis Lupus ◽  
Yellowstone National Park ◽  
National Park ◽  
Bison Bison ◽  
Unusual Behavior

Incidents are described of Bison (Bison bison) in Yellowstone National Park mauling and possibly killing a young Elk (Cervus elaphus) calf, chasing wolves (Canis lupus) off Elk they had just killed or were killing, and keeping the wolves away for extended periods. During one of the latter cases, the Bison knocked a wolf-wounded Elk down. Bison were also seen approaching wolves that were resting and sleeping, rousting them, following them to new resting places and repeating this behavior. These behaviors might represent some type of generalized hyper-defensiveness that functions as an anti-predator strategy.

scholarly journals Yellowstone wolf (Canis lupus) density predicted by elk (Cervus elaphus) biomass

2015 ◽  
Vol 93 (6) ◽  
pp. 499-502 ◽  
Author(s):  
L. David Mech ◽  
Shannon Barber-Meyer
Keyword(s):  
Cervus Elaphus ◽  
Canis Lupus ◽  
Yellowstone National Park ◽  
National Park ◽  
Population Fluctuations ◽  
Biomass Density ◽  
Gray Wolves ◽  
Prey Biomass ◽  
Prey System ◽  
Using Data

The Northern Range (NR) of Yellowstone National Park (YNP) hosts a higher prey biomass density in the form of elk (Cervus elaphus L., 1758) than any other system of gray wolves (Canis lupus L., 1758) and prey reported. Therefore, it is important to determine whether that wolf–prey system fits a long-standing model relating wolf density to prey biomass. Using data from 2005 to 2012 after elk population fluctuations dampened 10 years subsequent to wolf reintroduction, we found that NR prey biomass predicted wolf density. This finding and the trajectory of the regression extend the validity of the model to prey densities 19% higher than previous data and suggest that the model would apply to wolf–prey systems of even higher prey biomass.

Wolves, elk, and bison: reestablishing the "landscape of fear" in Yellowstone National Park, U.S.A.

2001 ◽  
Vol 79 (8) ◽  
pp. 1401-1409 ◽  
Author(s):  
John W Laundré ◽  
Lucina Hernández ◽  
Kelly B Altendorf
Keyword(s):  
Cervus Elaphus ◽  
Canis Lupus ◽  
Yellowstone National Park ◽  
National Park ◽  
Social Groups ◽  
Bison Bison ◽  
Landscape Of Fear ◽  
Behavioural Responses ◽  
The Social ◽  
Second Year

The elk or wapiti (Cervus elaphus) and bison (Bison bison) of Yellowstone National Park have lived in an environment free of wolves (Canis lupus) for the last 50 years. In the winter of 1994-1995, wolves were reintroduced into parts of Yellowstone National Park. Foraging theory predicts that elk and bison would respond to this threat by increasing their vigilance levels. We tested this prediction by comparing vigilance levels of elk and bison in areas with wolves with those of elk still in "wolf-free" zones of the Park. Male elk and bison showed no response to the reintroduction of wolves, maintaining the lowest levels of vigilance throughout the study ([Formula: see text]12 and 7% of the time was spent vigilant, respectively). Female elk and bison showed significantly higher vigilance levels in areas with wolves than in areas without wolves. The highest vigilance level (47.5 ± 4.1%; mean ± SE) was seen by the second year for female elk with calves in the areas with wolves and was maintained during the subsequent 3 years of the study. As wolves expanded into non-wolf areas, female elk with and without calves in these areas gradually increased their vigilance levels from initially 20.1 ± 3.5 and 11.5 ± 0.9% to 43.0 ± 5.9 and 30.5 ± 2.8% by the fifth year of the study, respectively. We discuss the possible reasons for the differences seen among the social groups. We suggest that these behavioural responses to the presence of wolves may have more far-reaching consequences for elk and bison ecology than the actual killing of individuals by wolves.

Kill rate by wolves on moose in the Yukon

2000 ◽  
Vol 78 (1) ◽  
pp. 49-59 ◽  
Author(s):  
R D Hayes ◽  
A M Baer ◽  
U Wotschikowsky ◽  
A S Harestad
Keyword(s):  
Canis Lupus ◽  
Snow Depth ◽  
Prey Density ◽  
Large Scale ◽  
Rangifer Tarandus ◽  
Prey Selection ◽  
Ecological Factors ◽  
Predation Rate ◽  
Wolf Predation ◽  
Kill Rate

We studied the kill rate by wolves (Canis lupus) after a large-scale wolf removal when populations of wolves, moose (Alces alces), and woodland caribou (Rangifer tarandus caribou) were all increasing. We followed a total of 21 wolf packs for 4 winters, measuring prey selection, kill rates, and ecological factors that could influence killing behavior. Wolf predation was found to be mainly additive on both moose and caribou populations. Kill rates by individual wolves were inversely related to pack size and unrelated to prey density or snow depth. Scavenging by ravens decreased the amount of prey biomass available for wolves to consume, especially for wolves in smaller packs. The kill rate by wolves on moose calves was not related to the number of calves available each winter. Wolves did not show a strong switching response away from moose as the ratio of caribou to moose increased in winter. The predation rate by wolves on moose was best modeled by the number and size of packs wolves were organized into each winter.

scholarly journals Resource-Driven Encounters and the Induction of Disease Among Consumers

2016 ◽  
Author(s):  
Rebecca K. Borchering ◽  
Steve E. Bellan ◽  
Jason M. Flynn ◽  
Juliet R.C. Pulliam ◽  
Scott A. McKinley
Keyword(s):  
National Park ◽  
Interaction Model ◽  
Spatially Explicit ◽  
Encounter Rate ◽  
Model Parameters ◽  
Expected Number ◽  
Spatially Explicit Model ◽  
Consumer Population ◽  
Using Data ◽  
The Relationship

AbstractSubmitted Manuscript 2016. Territorial animals share a variety of common resources, which can be a major driver of conspecific encounter rates. We examine how changes in resource availability influence the rate of encounters among individuals in a consumer population by implementing a spatially explicit model for resource visitation behavior by consumers. Using data from 2009 and 2010 in Etosha National Park, we verify our model's prediction that there is a saturation effect in the expected number of jackals that visit a given carcass site as carcasses become abundant. However, this does not directly imply that the overall resource-driven encounter rate among jackals decreases. This is because the increase in available carcasses is accompanied by an increase in the number of jackals that detect and potentially visit carcasses. Using simulations and mathematical analysis of our consumer-resource interaction model, we characterize key features of the relationship between resource-driven encounter rate and model parameters. These results are used to investigate a standing hypothesis that the outbreak of a fatal disease among zebras can potentially lead to an outbreak of an entirely different disease in the jackal population, a process we refer to as indirect induction of disease.

Coyote foraging ecology and vigilance in response to gray wolf reintroduction in Yellowstone National Park

2003 ◽  
Vol 81 (6) ◽  
pp. 985-993 ◽  
Author(s):  
T Adam Switalski
Keyword(s):  
Canis Lupus ◽  
Yellowstone National Park ◽  
National Park ◽  
Foraging Ecology ◽  
Canis Latrans ◽  
Gray Wolf ◽  
Trade Off ◽  
Cascading Effects ◽  
Large Carnivore ◽  
Continuous Source

Coyotes (Canis latrans) in Yellowstone National Park (YNP) have lived in the absence of wolves (Canis lupus) for over 60 years. I examined whether wolf reintroduction in 1995 and 1996 in YNP influenced coyote vigilance and foraging ecology. From December 1997 to July 2000, my co-workers and I collected 1708 h of coyote activity budgets. Once wolves became established in the Park, they once again provided a continuous source of carrion in the Lamar Valley and we found that coyotes began feeding on carcasses throughout the year. Although we documented that wolves killed coyotes, it also became clear that surviving coyotes quickly adjusted their behaviors when wolves were present. When coyotes were near wolves or in areas of high wolf use, they fed on carcasses much more; however, they increased the amount of time spent in vigilance activities and decreased rest. There appears to be a trade-off in which wolf kills provide a quick source of food that is energetically advantageous to coyotes; however, attendant costs included increased vigilance, decreased rest, and a higher risk of being killed. Changes in the behavior of coyotes in response to the reintroduction of this large carnivore may ultimately have wide-ranging cascading effects throughout the ecosystem.

Long-term aspen dynamics, trophic cascades, and climate in northern Yellowstone National Park

2016 ◽  
Vol 46 (4) ◽  
pp. 548-556 ◽  
Author(s):  
Robert L. Beschta ◽  
Luke E. Painter ◽  
Taal Levi ◽  
William J. Ripple
Keyword(s):  
Populus Tremuloides ◽  
Cervus Elaphus ◽  
Yellowstone National Park ◽  
National Park ◽  
Average Density ◽  
Drought Severity ◽  
Quaking Aspen ◽  
Climatic Trend ◽  
Predator Prey

We report long-term patterns of quaking aspen (Populus tremuloides Michx.) recruitment for five ungulate exclosures in the northern ungulate winter range of Yellowstone National Park. Aspen recruitment was low (<3 aspen·ha−1·year−1) in the mid-1900s prior to exclosure construction due to herbivory by Rocky Mountain elk (Cervus elaphus Linnaeus, 1758) but increased more than 60-fold within 25 years after exclosure construction despite a drying climatic trend since 1940. Results support the hypothesis that long-term aspen decline in Yellowstone’s northern range during the latter half of the 20th century was caused by high levels of ungulate herbivory and not a drying climate. Gray wolves (Canis lupus Linnaeus, 1758) were reintroduced during 1995–1996. For the period 1995–2012, we summarized annual predator–prey ratios, ungulate biomass, and drought severity. The average density of young aspen increased from 4350 aspen·ha−1 in 1997–1998 to 8960 aspen·ha−1 in 2012; during the same time period, those >1 m in height increased over 30-fold (from 105 to 3194 aspen·ha−1). Increased heights of young aspen occurred primarily from 2007 to 2012, a period with relatively high predator–prey ratios, declining elk numbers, and decreasing browsing rates. Consistent with a re-established trophic cascade, aspen stands in Yellowstone’s northern range have increasingly begun to recover.

Threat of predation: do ungulates behave aggressively towards different members of a coyote pack?

1999 ◽  
Vol 77 (3) ◽  
pp. 499-503 ◽  
Author(s):  
Eric M Gese
Keyword(s):  
Body Size ◽  
Aggressive Behavior ◽  
Cervus Elaphus ◽  
Yellowstone National Park ◽  
National Park ◽  
Bison Bison ◽  
Antilocapra Americana ◽  
Wild Canids ◽  
Pronghorn Antelope ◽  
Large Groups

Wild ungulates have evolved a variety of antipredator strategies to deter or escape predation by carnivores. Among wild canids, the dominant pair of a pack often initiates attacks upon prey. Previous observations in Yellowstone National Park, Wyoming, showed that the alpha pair in a coyote (Canis latrans) pack most often leads attacks on ungulates during winter. We were interested in determining whether ungulates can distinguish (perhaps by body size or posture) which members of a coyote pack are the alpha individuals, and whether they initiate and direct aggressive behavior towards those members of the pack that pose the greatest threat of predation to themselves and (or) their offspring. During 2507 h of behavioral observations on 54 coyotes between January 1991 and June 1993, we observed 51 interactions between coyotes and adult elk (Cervus elaphus), bison (Bison bison), and pronghorn antelope (Antilocapra americana) in Yellowstone National Park. The interactions analyzed here are those in which the ungulate appeared to initiate aggressive behavior towards the coyote(s) and were not a response to an attack by the predators. We found that aggression by ungulates towards coyotes was highest during the summer months, when calves and fawns were present; female ungulates were more frequently aggressive than males. The frequency of aggression of adult ungulates towards small and large groups of coyotes was equal to the frequency of occurrence of these groups. Ungulates directed aggressive behavior more frequently towards alpha coyotes and were less aggressive towards beta coyotes and pups. Large ungulates, particularly elk and bison, appeared to perceive that alpha coyotes posed a greater threat to themselves and their offspring. The smaller ungulate, the pronghorn antelope, directed aggressive behavior equally towards all coyotes. Adult ungulates were probably responding to the larger body size of the alpha coyotes and the tendency of alpha coyotes to travel at the front of the pack.

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