Elk population dynamics in areas with and without predation by recolonizing wolves in Banff National Park, Alberta

2002 ◽  
Vol 80 (5) ◽  
pp. 789-799 ◽  
Author(s):  
Mark Hebblewhite ◽  
Daniel H Pletscher ◽  
Paul C Paquet
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Cervus Elaphus ◽  
Snow Depth ◽  
National Park ◽  
Linear Models ◽  
Information Criteria ◽  
Factors Affecting ◽  
Wolf Predation ◽  
Banff National Park

Gray wolves (Canis lupus) recolonized the Bow Valley of Banff National Park in the mid-1980s after a 30-year absence. Wolves recolonized one zone of the Bow Valley in 1985 and another in 1991, but human activity excluded wolves from a third zone throughout the study. Elk (Cervus elaphus) are the primary prey of wolves in Banff National Park. We studied the effects of wolf predation, snow depth, elk density, and human-caused mortality on the elk population growth rate in the three different wolf recolonization treatments from 1985 to 2000. We constructed a set of generalized linear models of factors affecting population growth, and used Akaike Information Criteria to guide model selection and inference. In the low wolf predation zone, elk population growth was density-dependent and limited by human-caused mortality. In the zone that wolves recolonized in 1991, elk population growth was limited by the combined effects of snow depth and wolf predation after wolf recolonization, in addition to preexisting mortality caused by humans and other predators. Our correlative approach failed to yield insights into population dynamics in the zone where wolves were present throughout the study. However, by comparing zones we demonstrate important differences in ungulate population dynamics in the presence and absence of wolf predation.

Effects of elk group size on predation by wolves

2002 ◽  
Vol 80 (5) ◽  
pp. 800-809 ◽  
Author(s):  
Mark Hebblewhite ◽  
Daniel H Pletscher
Keyword(s):  
Predation Risk ◽  
Group Size ◽  
Cervus Elaphus ◽  
Canis Lupus ◽  
National Park ◽  
Risk Model ◽  
Wolf Predation ◽  
Banff National Park ◽  
Density Relationship ◽  
Large Groups

Wolf-prey research has focused on single-prey systems in North America dominated by moose (Alces alces) or white-tailed deer (Odocoileus virginianus). Elk (Cervus elaphus) are social ungulates and the main prey item of wolves (Canis lupus) in Banff National Park (BNP), Alberta. Grouping behaviour may affect the functional response of predators by changing how predators encounter and kill prey. We studied wolf predation on elk in BNP during the winters of 1997–1998 and 1998–1999 and tested how elk group size affected the availability of and encounter rates with elk groups and attack success of wolves. Wolves encountered larger elk groups than expected based on availability, and killed more elk from large groups than expected based on numbers of encounters. Elk group size increased with elk density in BNP. Increased rates of encounter with and success of attacking large elk groups, and the positive group size – density relationship may be a mechanism for density-dependent predation. We developed a predation-risk model to test the prediction that grouping will benefit individual elk, given this predation regime. Elk appeared to adopt two different strategies to minimize predation risk: living in small herds that were rarely encountered by wolves or living in large herds that reduced their predation risk through dilution.

Prey selectivity of wolves in Banff National Park. I. Prey species

1993 ◽  
Vol 71 (1) ◽  
pp. 130-139 ◽  
Author(s):  
David J. Huggard
Keyword(s):  
National Park ◽  
Prey Type ◽  
Prey Selectivity ◽  
Functional Responses ◽  
Encounter Rates ◽  
Factors Affecting ◽  
Habitat Overlap ◽  
Banff National Park ◽  
Mountain Goats ◽  
Number Of Individuals

I examined the components generating selectivity in wolves preying on five ungulate species in Banff National Park, Alberta. Overall selectivity for elk and deer species, and apparent avoidance of bighorn sheep and mountain goats, were due primarily to lower habitat overlap of wolves with the latter two species, and therefore lower encounter rates. For social ungulates, I argue that the herd should be considered the unit of encounter, with encounter rates proportional to the number of herds rather than the number of individuals. However, large herds predictably associated with certain areas may be visited intentionally by wolves, increasing effective encounter rates. Foraging theory suggests that all ungulate prey should be equally profitable to wolves upon encounter and therefore the factors affecting encounter rates are critical in determining prey selectivity. A simple model incorporating different habitat overlap, herd sizes, and predictable herds predicts qualitatively different functional responses of wolves to changes in density of the different prey types. The model also demonstrates how apparent selectivity for a prey type can result from the different ways in which prey are encountered.

scholarly journals Factors affecting reproduction and population growth in a restored elk Cervus elaphus nelsoni population

2002 ◽  
Vol 8 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Jeffery L. Larkin ◽  
David S. Maehr ◽  
John J. Cox ◽  
Michael W. Wichrowski ◽  
R. Daniel Crank
Keyword(s):  
Population Growth ◽  
Cervus Elaphus ◽  
Factors Affecting ◽  
Cervus Elaphus Nelsoni

scholarly journals Elk Movements, Habitat use, and Population Dynamics in Theodore Roosevelt National Park

1988 ◽  
Vol 12 ◽  
pp. 163-170
Author(s):  
Lynn Irby ◽  
Clayton Marlow ◽  
Harold Picton ◽  
Jerry Westfall
Keyword(s):  
Population Dynamics ◽  
Cervus Elaphus ◽  
National Park ◽  
Human Impacts ◽  
Habitat Types ◽  
Theodore Roosevelt ◽  
Seasonal Movements ◽  
Theodore Roosevelt National Park ◽  
Important Habitat

Objectives: 1. Description of daily and seasonal movements of elk (Cervus elaphus); 2. Identification of seasonally important habitat types and physiographic character of areas used for feeding, cover, mating, and calving; 3. Identification of damage to Park resources or property of adjoining landowners by elk; 4. Description of interactions between elk and other ungulates and identification of interactions that could detrimentally affect specific ungulate species; 5. Determination of human impacts on elk behavior and distribution in the Park; and 6. Description of elk age structure, productivity, and survivorship during 1987-88 and development of population goals that are consistent with Park management goals.

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 Trophic Cascades and Historic Aspen Recruitment in the Gallatin Elk Winter Range of Southwest Montana

2005 ◽  
Vol 29 ◽  
pp. 89-95
Author(s):  
Joshua Halofsky ◽  
William Ripple
Keyword(s):  
Populus Tremuloides ◽  
Cervus Elaphus ◽  
Canis Lupus ◽  
National Park ◽  
Fire Suppression ◽  
Gray Wolf ◽  
Climate Trends ◽  
Wolf Predation ◽  
Winter Range ◽  
Conifer Invasion

The extirpation of the gray wolf (Canis lupus) by 1930 in Yellowstone National Park (YNP) provided us with an opportunity to study historic aspen (Populus tremuloides ) recruitment with and without a top carnivore predator present. Herbivory, climate trends, fire records, and current conifer invasion were also examined within the context of aspen recruitment. We obtained tree cores and diameter at breast height measurements to create an aspen age-diameter relationship which we used to approximate aspen origination dates. One elk (Cervus elaphus) exclosure, erected in 1945 within the same elk winter range, was compared to the rest of the winter range. Consistent recruitment inside the exclosure began in the 1940s and has continued into the present. Outside of the exclosure, aspen recruitment began decreasing in the 1930s and ceased in the 1950s. Within the scope of the study, we found little correlative evidence between aspen decline and climate trends, conifer invasion, or fire suppression. The results are suggestive of a trophic cascade between aspen recruitment, and historical elk browsing activities as affected by the absence or presence of wolf predation.

Prey selectivity of wolves in Banff National Park. II. Age, sex, and condition of elk

1993 ◽  
Vol 71 (1) ◽  
pp. 140-147 ◽  
Author(s):  
David J. Huggard
Keyword(s):  
National Park ◽  
Age Distribution ◽  
Adult Males ◽  
Prey Selectivity ◽  
Marrow Fat ◽  
Wolf Predation ◽  
The Road ◽  
Banff National Park ◽  
Males And Females ◽  
On The Road

Wolf predation on elk was studied in Banff National Park, Alberta. Overall, wolves took a higher proportion of adult males and calves than occurred in the population. However, wolves encounter elk as herds rather than individuals, and when the herd is considered to be the unit of available prey, calves are highly selected for compared with both adult males and females. Adult elk killed by wolves were older than those killed on the road or railway, but a simple model showed that this result can be caused by a bias in obtaining the population age distribution from a mortality source. Jaw lengths and antler characteristics of wolf kills did not differ from those of road and rail kills. Adult elk, but not calves, killed by wolves had lower reserves of marrow fat than elk killed on the road and railway.

scholarly journals Elk Movements, Habitat Use, and Population Dynamics in Theodore Roosevelt National Park

1987 ◽  
Vol 11 ◽  
pp. 143-149
Author(s):  
Lynn Irby ◽  
Clayton Marlow ◽  
Harold Picton ◽  
Jerry Westfall
Keyword(s):  
Population Dynamics ◽  
Cervus Elaphus ◽  
National Park ◽  
Human Impacts ◽  
Habitat Types ◽  
Theodore Roosevelt ◽  
Seasonal Movements ◽  
Theodore Roosevelt National Park ◽  
Important Habitat

Objectives 1) Description of daily and seasonal movements of elk (Cervus elaphus); 2) Identification of seasonally important habitat types and physiographic character of areas used for feeding, cover, mating, and calving; 3) Identification of damage to Park resources or property of adjoining landowners by elk; 4) Description of interactions between elk and other ungulates and identification of interactions that could detrimentally affect specific ungulate species; 5) Determination of human impacts on elk behavior and distribution in the Park; and 6) Description of elk age structure, productivity, and survivorship during 1987-88 and development of population goals that are consistent with Park management goals.

scholarly journals Elk population dynamics when carrying capacities vary within and among herds

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lisa J. Koetke ◽  
Adam Duarte ◽  
Floyd W. Weckerly
Keyword(s):  
Population Dynamics ◽  
Population Growth ◽  
Temporal Variation ◽  
Cervus Elaphus ◽  
Population Regulation ◽  
Growth Parameters ◽  
Growth Models ◽  
Stochastic Fluctuation ◽  
Stochastic Fluctuations ◽  
Population Growth Parameters

Abstract Population and land management relies on understanding population regulation and growth, which may be impacted by variation in population growth parameters within and among populations. We explored the interactions between variation in carrying capacity (K), intrinsic population growth rate (r), and strength of density dependence (β) within and among elk (Cervus elaphus) herds in a small part of the geographic range of the species. We also estimated stochastic fluctuations in abundance around K for each herd. We fit linear Ricker growth models using Bayesian statistics to seven time series of elk population survey data. Our results indicate that K and β varied among herds, and that r and β varied temporally within herds. We also found that herds with smaller K had less stochastic fluctuation in abundances around K, but higher temporal variation in β within herds. Population regulation and the rate of return to the equilibrium abundance is often understood in terms of β, but ecological populations are dynamic systems, and temporal variation in population growth parameters may also influence regulation. Population models which accommodate variation both within and among herds in population growth parameters are necessary, even in mild climates, to fully understand population dynamics and manage populations.

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