Does Wolf Predation Alone Limit the Moose Population in Pukaskwa Park?: A Comment

The expansion of moose into southern British Columbia caused the decline and extirpation of woodland caribou due to their shared predators, a process commonly referred to as apparent competition. Using an adaptive management experiment, we tested the hypothesis that reducing moose to historic levels would reduce apparent competition and therefor recover caribou populations. Nested within this broad hypothesis were three specific hypotheses: 1) sport hunting could be used to substantially reduce moose numbers to an ecological target; 2) wolves in this ecosystem were primarily limited by moose abundance; and 3) caribou were limited by wolf predation. These hypotheses were evaluated with a before-after control-impact (BACI) design that included response metrics such as population trends and vital rates of caribou, moose, and wolves. Three caribou subpopulations were subject to the moose reduction treatment and two were in a reference area where moose were not reduced. When the moose harvest was increased, the moose population declined substantially in the treatment area (by 70%) but not the reference area, suggesting that the policy had the desired effect and was not caused by a broader climatic process. Wolf numbers subsequently declined in the treatment area, with wolf dispersal rates 2.5 × greater, meaning that dispersal was the likely mechanism behind the wolf numerical response, though reduced recruitment and starvation was also documented in the treatment area. Caribou adult survival increased from 0.78 to 0.88 in the treatment area, but declined in the reference. Caribou recruitment was unaffected by the treatment. The largest caribou subpopulation stabilized in the treatment area, but declined in the reference area. The observed population stability is comparable to other studies that used intensive wolf control, but is insufficient to achieve recovery, suggesting that multiple limiting factors and corresponding management tools must be addressed simultaneously to achieve population growth.

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Experimental moose reduction lowers wolf density and stops decline of endangered caribou

PeerJ ◽

10.7717/peerj.3736 ◽

2017 ◽

Vol 5 ◽

pp. e3736 ◽

Cited By ~ 22

Author(s):

Robert Serrouya ◽

Bruce N. McLellan ◽

Harry van Oort ◽

Garth Mowat ◽

Stan Boutin

Keyword(s):

Apparent Competition ◽

Limiting Factors ◽

Adult Survival ◽

Population Stability ◽

Vital Rates ◽

Reference Area ◽

Treatment Area ◽

Management Tools ◽

Wolf Predation ◽

Moose Population

The expansion of moose into southern British Columbia caused the decline and extirpation of woodland caribou due to their shared predators, a process commonly referred to as apparent competition. Using an adaptive management experiment, we tested the hypothesis that reducing moose to historic levels would reduce apparent competition and therefor recover caribou populations. Nested within this broad hypothesis were three specific hypotheses: (1) sport hunting could be used to substantially reduce moose numbers to an ecological target; (2) wolves in this ecosystem were primarily limited by moose abundance; and (3) caribou were limited by wolf predation. These hypotheses were evaluated with a before-after control-impact (BACI) design that included response metrics such as population trends and vital rates of caribou, moose, and wolves. Three caribou subpopulations were subject to the moose reduction treatment and two were in a reference area where moose were not reduced. When the moose harvest was increased, the moose population declined substantially in the treatment area (by 70%) but not the reference area, suggesting that the policy had the desired effect and was not caused by a broader climatic process. Wolf numbers subsequently declined in the treatment area, with wolf dispersal rates 2.5× greater, meaning that dispersal was the likely mechanism behind the wolf numerical response, though reduced recruitment and starvation was also documented in the treatment area. Caribou adult survival increased from 0.78 to 0.88 in the treatment area, but declined in the reference. Caribou recruitment was unaffected by the treatment. The largest caribou subpopulation stabilized in the treatment area, but declined in the reference area. The observed population stability is comparable to other studies that used intensive wolf control, but is insufficient to achieve recovery, suggesting that multiple limiting factors and corresponding management tools must be addressed simultaneously to achieve population growth.

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

Canadian Journal of Zoology ◽

10.1139/z89-029 ◽

1989 ◽

Vol 67 (1) ◽

pp. 216-219 ◽

Cited By ~ 11

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.

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Wolf functional response and regulation of moose in the Yukon

Canadian Journal of Zoology ◽

10.1139/z99-188 ◽

2000 ◽

Vol 78 (1) ◽

pp. 60-66 ◽

Cited By ~ 35

Author(s):

R D Hayes ◽

A S Harestad

Keyword(s):

Functional Response ◽

Canis Lupus ◽

Response Curve ◽

Predation Rate ◽

Type Ii ◽

Prey Switching ◽

East Central ◽

Wolf Predation ◽

Interior Alaska ◽

Moose Population

We studied kill rates by wolves (Canis lupus) on a rapidly growing moose population in the east-central Yukon. We added these data to the cumulative functional response curve obtained in other North American wolf studies. Our kill rates are higher than those predicted at low moose densities. The kill rate increases rapidly, reaching 2.4 moose per wolf per 100 days at 0.26 moose/km2 and remains constant at this level. No data are available below 0.2 moose/km2 to indicate the shape of the ascending curve. Based on moose distribution and the low prey-switching ability of wolves, we suggest that the functional response curve is of type II. Our wolf predation rate model predicts that moose are held to a low density equilibrium between 0.07 and 0.12/km2, slightly below densities observed in interior Alaska and the Yukon.

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Experimental moose reduction lowers wolf density and stops decline of endangered caribou

10.7287/peerj.preprints.3108 ◽

2017 ◽

Author(s):

Robert Serrouya ◽

Bruce N McLellan ◽

Harry van Oort ◽

Garth Mowat ◽

Stan Boutin

Keyword(s):

Apparent Competition ◽

Limiting Factors ◽

Adult Survival ◽

Population Stability ◽

Vital Rates ◽

Reference Area ◽

Treatment Area ◽

Management Tools ◽

Wolf Predation ◽

Moose Population

The expansion of moose into southern British Columbia caused the decline and extirpation of woodland caribou due to their shared predators, a process commonly referred to as apparent competition. Using an adaptive management experiment, we tested the hypothesis that reducing moose to historic levels would reduce apparent competition and therefor recover caribou populations. Nested within this broad hypothesis were three specific hypotheses: 1) sport hunting could be used to substantially reduce moose numbers to an ecological target; 2) wolves in this ecosystem were primarily limited by moose abundance; and 3) caribou were limited by wolf predation. These hypotheses were evaluated with a before-after control-impact (BACI) design that included response metrics such as population trends and vital rates of caribou, moose, and wolves. Three caribou subpopulations were subject to the moose reduction treatment and two were in a reference area where moose were not reduced. When the moose harvest was increased, the moose population declined substantially in the treatment area (by 70%) but not the reference area, suggesting that the policy had the desired effect and was not caused by a broader climatic process. Wolf numbers subsequently declined in the treatment area, with wolf dispersal rates 2.5 × greater, meaning that dispersal was the likely mechanism behind the wolf numerical response, though reduced recruitment and starvation was also documented in the treatment area. Caribou adult survival increased from 0.78 to 0.88 in the treatment area, but declined in the reference. Caribou recruitment was unaffected by the treatment. The largest caribou subpopulation stabilized in the treatment area, but declined in the reference area. The observed population stability is comparable to other studies that used intensive wolf control, but is insufficient to achieve recovery, suggesting that multiple limiting factors and corresponding management tools must be addressed simultaneously to achieve population growth.

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Comparison of the Benzanthrone Luminophores: They Are Not Equal for Rapid Examination of Parafasciolopsis fasciolaemorpha (Trematoda: Digenea)

Biomolecules ◽

10.3390/biom11040598 ◽

2021 ◽

Vol 11 (4) ◽

pp. 598

Author(s):

Ilze Rubenina ◽

Inese Gavarane ◽

Elena Kirilova ◽

Ligita Mezaraupe ◽

Muza Kirjusina

Keyword(s):

Tertiary Amine ◽

Laser Scanning ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Amine Group ◽

Tertiary Amine Group ◽

Organ Systems ◽

Staining Protocol ◽

Anatomical Arrangement ◽

Moose Population

Luminescent derivatives of benzanthrone are becoming more useful based on their light-absorbing and fluorescent-emitting properties. Our previous studies showed that luminescent staining properties of the same benzanthrone dye differ for variable parasite samples. Therefore, two types of benzanthrone dyes were prepared. One has a strongly basic amidine group and a halogen atom, and the other has an amide moiety and a tertiary amine group. Trematoda Parafasciolopsis fasciolaemorpha is a liver fluke of a moose (Alces alces) and has a significant influence on the health and abundance of the moose population. Staining protocols for parasite P. fasciolaemorpha specific organ or organ systems imaging are mostly time-consuming and labor-intensive. The study aimed to compare the fixation technique and the staining protocol by synthesized benzanthrone luminescent dyes to determine detailed morphology, anatomical arrangement of the organ systems and gross organization of the muscle layers of P. fasciolaemorpha using confocal laser scanning microscopy. Luminophores were tested for samples fixed in different fixatives. Developed dyes and staining protocol resulting in imaging of all parts of trematode without additional sample preparation procedures, which usually are required for parasite examination. Obtained results confirmed that the most qualitative results could be reached using 3-N-(2-piperidinylacetamido)benzanthrone dye which has amide moiety and a tertiary amine group. Based on obtained results, 3-N-(2-piperidinylacetamido)benzanthrone gave more qualitative parasite visualization than 2-bromo-3-N-(N′,N′-dimethylformamidino)benzanthrone.

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Interactions of sapsuckers and Cytospora canker can facilitate decline of riparian willows

Botany ◽

10.1139/cjb-2014-0019 ◽

2014 ◽

Vol 92 (7) ◽

pp. 485-493 ◽

Cited By ~ 3

Author(s):

Kristen M. Kaczynski ◽

David J. Cooper ◽

William R. Jacobi

Keyword(s):

Large Scale ◽

Temporal Dynamics ◽

Rocky Mountain ◽

Aerial Photo ◽

Stream Flows ◽

The Past ◽

Cytospora Chrysosperma ◽

Willow Bark ◽

Moose Population ◽

Cytospora Canker

Drought has caused large-scale plant mortality in ecosystems around the globe. Most diebacks have affected upland forest species. In the past two decades, a large-scale decline of riparian willows (Salix L.) has occurred in Rocky Mountain National Park, Colorado. We examined whether climatic or biotic factors drive and maintain the willow community decline. We compared annual growth and dieback of willows inside and outside of 14-year-old ungulate exclosures and measured groundwater depth and predawn xylem pressures of stems as indicators of drought stress. We also performed an aerial photo analysis to determine the temporal dynamics of the decline. Aerial photo analysis indicated willow decline occurred between 2001 and 2005 and was best explained by an increase in moose population and a decrease in peak stream flows. A new mechanism for willow stem dieback was identified, initiated by red-naped sapsucker wounding willow bark. Wounds became infected with fungus that girdled the stem. DNA analyses confirmed Valsa sordida (Cytospora chrysosperma) as the lethal fungus. Captured sapsuckers had V. sordida spores on feet and beaks identifying them as one possible vector of spread. Predawn xylem pressure potentials remained high through the growing season on all study willows regardless of depth to ground water. Our results indicate that additional mechanisms may be involved in tall willow decline.

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

Canadian Journal of Zoology ◽

10.1139/z98-083 ◽

1998 ◽

Vol 76 (8) ◽

pp. 1551-1569 ◽

Cited By ~ 32

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.

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Kill rate by wolves on moose in the Yukon

Canadian Journal of Zoology ◽

10.1139/z99-187 ◽

2000 ◽

Vol 78 (1) ◽

pp. 49-59 ◽

Cited By ~ 48

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.

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