Comment: Regulation of moose populations by wolf predation

2000 ◽  
Vol 78 (3) ◽  
pp. 506-510 ◽  
Author(s):  
François Messier ◽  
Damien O Joly
Keyword(s):  
Density Dependence ◽  
Canis Lupus ◽  
Recent Article ◽  
Prey Density ◽  
Regulatory Effect ◽  
Wolf Population ◽  
Regulatory Factor ◽  
Killing Rate ◽  
Wolf Predation ◽  
Present Understanding

We discuss regulation of moose (Alces alces) populations by wolves (Canis lupus) in the context of a recent article by Eberhardt (L.L. Eberhardt. 1997. Can. J. Zool. 75: 1940-1944), who contended that the killing rate of moose by wolves was constant. Further, he argued that wolf population size was proportional to prey density, and that wolf predation exerted a regulatory effect on ungulate-prey numbers. We argue that this combination of functional and numerical responses results in density-independent predation that cannot regulate prey numbers. We discuss the present understanding of wolf-moose interactions and conclude that there is evidence suggesting density dependence in both functional and numerical responses. Further, we conclude that predation by wolves is density-dependent, at least at low moose densities, and therefore can act as a regulatory factor.

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.

Echinococcus granulosus (Cestoda: Taeniidae) infections and moose – wolf population dynamics in southwestern Quebec

1989 ◽  
Vol 67 (1) ◽  
pp. 216-219 ◽  
Author(s):  
François Messier ◽  
Manfred E. Rau ◽  
Marilyn A. McNeill
Keyword(s):  
Population Dynamics ◽  
Echinococcus Granulosus ◽  
Definitive Host ◽  
Total Weight ◽  
Regulatory Effect ◽  
Wolf Population ◽  
Use Of Space ◽  
Wolf Predation ◽  
Aggregated Distribution ◽  
Moose Population

The prevalence, mean number, and mean total weight of Echinococcus granulosus cysts in the lungs of moose increased with moose density in southwestern Quebec. Such responses in the level of infection were documented in areas of 0.17, 0.23, and 0.37 moose/km2. The increase of E. granulosus infection in moose was attributed to higher densities of wolves, the definitive host of this parasite, as well as an accompanying increase in the rate of wolf predation upon moose. The aggregated distribution of this parasite within the moose population is considered to reflect the highly heterogeneous use of space by wolves and the consequent aggregated distribution of parasite eggs within the environment. A possible regulatory effect of E. granulosus infections on moose numbers is discussed.

Is wolf predation ratio-dependent?

1997 ◽  
Vol 75 (11) ◽  
pp. 1940-1944 ◽  
Author(s):  
L. L. Eberhardt
Keyword(s):  
Canis Lupus ◽  
Alces Alces ◽  
Predator Control ◽  
Regulatory Effect ◽  
Predator Prey ◽  
Wolf Predation ◽  
Predator Prey Model ◽  
Prey Model ◽  
Data Limitations ◽  
Ratio Dependent

The controversy over whether wolves (Canis lupus) can regulate ungulate numbers is difficult to assess, owing to data limitations, relaxation of predator control, and the fact that current predator – prey theory was developed from the study of invertebrate populations. A ratio-dependent predator – prey model appears to be supported by data on predation on ungulates, and the data indicate that wolves have a significant impact on numbers of moose (Alces alces), and thus can exert a regulatory effect on that species.

Wolf predation in a multiple-ungulate system in northern British Columbia

1998 ◽  
Vol 76 (8) ◽  
pp. 1551-1569 ◽  
Author(s):  
A T Bergerud ◽  
J P Elliott
Keyword(s):  
British Columbia ◽  
Canis Lupus ◽  
Birth Rate ◽  
Rangifer Tarandus ◽  
Adult Mortality ◽  
Recruitment Rate ◽  
Wolf Predation ◽  
Rate Of Increase ◽  
Ovis Dalli ◽  
Hunting Statistics

Caribou (Rangifer tarandus), elk (Cervus canadensis), moose (Alces alces), and Stone's sheep (Ovis dalli stonei) were either decreasing or stable in numbers in two areas in northeastern British Columbia in 1981-1982, prior to reductions in wolf (Canis lupus) numbers. Following the reduction of wolf numbers, recruitment improved 2-5 times for all four species, and all populations increased, based on either hunting statistics, census results, and (or) recruitments greater than 24 offspring at 9 months of age per 100 females. Recruitment of offspring at 9 months of age, when regressed against wolf numbers, declined with decelerating slopes for all four species. This inverse functional response is hypothesized to result from the preparturient spacing of females to reduce predation risk, and in this regard moose seem the least secure and sheep the most effectively spaced. For the four species, mean recruitment at 9 months of age that balanced adult mortality and provided a finite rate of increase of 1.00 was 24.16 ± 0.91 offspring/100 females (n = 11, coefficient of variation = 12.5%). The predicted recruitment rate for all four species in the absence of wolves was 53-57 offspring/100 females. But the birth rate of moose was much higher than those of the other species, indicating greater loss to other factors of which bear predation may be the greatest. Following wolf reductions of 60-86% of entire travelling packs, the wolves quickly recolonized the removal zones, with rates of increase ranging from 1.5 to 5.6.

Wolf predation risk associated with white-tailed deer movements

1991 ◽  
Vol 69 (10) ◽  
pp. 2696-2699 ◽  
Author(s):  
Michael E. Nelson ◽  
L. David Mech
Keyword(s):  
Predation Risk ◽  
Odocoileus Virginianus ◽  
Canis Lupus ◽  
Climatic Conditions ◽  
Male And Female ◽  
Wolf Predation ◽  
Adult Females ◽  
Disproportionate Number ◽  
Short Time ◽  
Antipredator Strategy

The survival of 159 yearling and adult deer (Odocoileus virginianus) was monitored by telemetry during 282 spring and 219 fall individual migrations to winter deeryards in northeastern Minnesota. A disproportionate number of deer were killed by wolves (Canis lupus) during fall migration relative to the short time they spent migrating, but not during spring migration. Predation was also significantly greater for male and female yearlings and adult females outside deeryards during winter. Survival of 79 yearlings dispersing from natal ranges was high (1.00). It appears that changing climatic conditions combined with unfamiliar terrain and undetermined factors predispose migratory deer to wolf predation during fall. These findings support an earlier hypothesis that winter yarding is an antipredator strategy.

scholarly journals Pack Size of Wolves, Canis lupus, on Caribou, Rangifer tarandus, Winter Ranges in Westcentral Alberta

2006 ◽  
Vol 120 (3) ◽  
pp. 313 ◽  
Author(s):  
Gerald W. Kuzyk ◽  
Jeff Kneteman ◽  
Fiona K. A. Schmiegelow
Keyword(s):  
Canis Lupus ◽  
Landscape Change ◽  
Rangifer Tarandus ◽  
Prey Size ◽  
Rocky Mountain ◽  
Predation Pressure ◽  
Resource Extraction ◽  
Rangifer Tarandus Caribou ◽  
Pack Size ◽  
Wolf Predation

We studied pack size of Wolves (Canis lupus) on Woodland Caribou (Rangifer tarandus caribou) winter ranges in westcentral Alberta. These Caribou winter ranges are experiencing increasing pressure from resource extraction industries (forestry, energy sector) and concerns have been raised regarding increased Wolf predation pressure on Caribou in conjunction with landscape change. Thirty-one Wolves, from eight Wolf packs, were fitted with radiocollars on two Caribou winter ranges in the Rocky Mountain foothills, near Grande Cache, Alberta (2000-2001). There was a mean of 8.2 Wolves/pack and between 30 and 39 Wolves on each of the RedRock/Prairie Creek and Little Smoky Caribou ranges. The average pack size of Wolves in this region does not appear to have increased over that recorded historically, but the range (5-18) in the number of Wolves per pack varied considerably over our study area. Wolves preyed predominately on Moose (Alces alces), averaging one Moose kill every three to five days. There was some indication that pack size was related to prey size, with the smallest pack preying on Deer (Odocoileus spp.). It was clear that Caribou could not be the primary prey for Wolves, due to their low numbers, and relative to the pack size and Wolf kills we observed.

Reply: Predator-prey ratio dependence and regulation of moose populations

2000 ◽  
Vol 78 (3) ◽  
pp. 511-513 ◽  
Author(s):  
L L Eberhardt
Keyword(s):  
Canis Lupus ◽  
Secondary Data ◽  
Data Sources ◽  
Prey Abundance ◽  
Regulatory Effect ◽  
Equilibrium Conditions ◽  
Predator Prey ◽  
Ratio Dependence ◽  
Secondary Data Sources ◽  
Non Equilibrium

The comment by Messier and Joly on a paper by Eberhardt (L.L. Eberhardt. 1997. Can. J. Zool. 75: 1940-1944) suggests that the data in the earlier paper do not demonstrate a regulatory effect of wolves (Canis lupus) on their ungulate prey. It appears that the disagreement results from the use of quite different models, with Messier's approach (F. Messier. 1994. Ecology, 75: 478-488) apparently depending on the assumption of an equilibrium between wolf abundance and prey abundance, while Eberhardt's model depicts non-equilibrium conditions. Some questions having to do with duplications in secondary data sources are further examined.

Behavioral responses of coyotes to wolf recolonization in northwestern Montana

1999 ◽  
Vol 77 (12) ◽  
pp. 1919-1927 ◽  
Author(s):  
Wendy M Arjo ◽  
Daniel H Pletscher
Keyword(s):  
Canis Lupus ◽  
Behavioral Responses ◽  
Behavioral Changes ◽  
Home Ranges ◽  
Wolf Population ◽  
Temporal Separation ◽  
Temporal Partitioning ◽  
Northwestern Montana ◽  
Range Overlap ◽  
Overlap Area

Recent recolonization of northwestern Montana by wolves (Canis lupus) provided an opportunity to examine behavioral responses of coyotes (Canis latrans) to a reestablished wolf population. Coyote and wolf annual home ranges overlapped extensively; however, seasonal overlap was not as pronounced. Most seasonal coyote home ranges were located between wolf packs or along the edge of wolf territories, but wolves and coyotes did not use the seasonal overlap area differently than expected. Most of the coyotes maintained random separation distances from wolves, though three coyotes were closer to wolves than expected. No difference in summer activity was found between the canids; however, temporal partitioning occurred during the winter, which may have allowed the increase in home-range overlap observed during the winter. Additionally, temporal partitioning occurred through differential arrangement of canid home ranges (i.e., wolf home ranges were smaller in summer) and reduced overlap of seasonal home ranges. Coyotes were usually singletons and some pairs, and before wolf colonization they fed on lagomorphs and plants. After wolf colonization, coyotes tended to be in pairs and small packs and they relied on ungulates. Although we documented wolves killing coyotes, coyotes are coexisting with wolves through spatial and temporal separation and behavioral changes.

Social organization, spatial distribution, and population density of wolves in relation to moose density

1985 ◽  
Vol 63 (5) ◽  
pp. 1068-1077 ◽  
Author(s):  
François Messier
Keyword(s):  
Spatial Distribution ◽  
Mortality Rate ◽  
Population Density ◽  
Social Organization ◽  
Prey Density ◽  
Territory Size ◽  
Wolf Population ◽  
Pack Size ◽  
Behavioral Attributes ◽  
Density Threshold

This 4-year study compared population density and related behavioral attributes of wolves (14 packs) at two different moose densities: 0.23 (LP, low prey density), and 0.37 (HP, high prey density) moose∙km−2. Wolf densities in January averaged 0.8 and 1.4 animals∙100 km−2, packs consisted of 3.7 and 5.7 individuals, year-long territory sizes were 255 and 390 km2, and interstices between territories represented 30 and [Formula: see text] of available area, for the LP and HP areas, respectively. Territory size increased significantly with pack size. The LP wolf population suffered from a higher mortality rate owing to a higher occurrence of deaths from malnutrition and intraspecific strife, and from a lower success in producing pups (61% of the possible occasions, compared with 93% in HP). When no other ungulate species is present, a density of 0.2 moose∙km−2 would approximate the density threshold below which a pack could not subsist and (or) reproduce successfully. The study reveals that naturally regulated moose–wolf systems may stabilize at low prey and low predator densities.

Managing wolves (Canis lupus) to recover threatened woodland caribou (Rangifer tarandus caribou) in Alberta

2014 ◽  
Vol 92 (12) ◽  
pp. 1029-1037 ◽  
Author(s):  
Dave Hervieux ◽  
Mark Hebblewhite ◽  
Dave Stepnisky ◽  
Michelle Bacon ◽  
Stan Boutin
Keyword(s):  
Canis Lupus ◽  
Rangifer Tarandus ◽  
Apparent Competition ◽  
Provincial Government ◽  
Population Increase ◽  
Rangifer Tarandus Caribou ◽  
Wolf Population ◽  
Woodland Caribou ◽  
Population Reduction ◽  
Reduction Program

Across Canada, woodland caribou (Rangifer tarandus caribou (Gmelin, 1788)) populations are declining because of human-induced changes to food webs that are resulting in apparent competition-induced increases in predator-caused caribou mortality. We tested the hypothesis that wolf (Canis lupus L., 1758) population reduction could reverse declines in a woodland caribou population following a BACI (before-after-control-impact) design conducted over a 12-year period in west-central Alberta, Canada. We monitored annual survival for 172 adult female caribou and calf recruitment from 2000 through 2012 and conducted a provincial government delivered wolf population reduction program annually during the winters of 2005–2006 to 2012 (inclusive) in an area centered on the Little Smoky range. Wolf removal translated to a 4.6% increase in mean population growth rate of the Little Smoky population mostly through improvements in calf recruitment. In contrast, the Red Rock Prairie Creek control population exhibited a 4.7% decline. Although the wolf population reduction program appeared to stabilize the Little Smoky population, it did not lead to population increase, however, with λ remaining approximately equal to 1. Therefore, we recommend, if required, predation management be combined with effective habitat conservation and long-term planning to effect the recovery of species, such as woodland caribou, which are declining as a result of habitat-mediated apparent competition.

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