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Laporte I.,University of Calgary | Muhly T.B.,University of Calgary | Pitt J.A.,University of Alberta | Alexander M.,Alberta Sustainable Resource Development | Musiani M.,University of Calgary
PLoS ONE | Year: 2010

Background: In many areas, livestock are grazed within wolf (Canis lupus) range. Predation and harassment of livestock by wolves creates conflict and is a significant challenge for wolf conservation. Wild prey, such as elk (Cervus elaphus), perform anti-predator behaviors. Artificial selection of cattle (Bos taurus) might have resulted in attenuation or absence of antipredator responses, or in erratic and inconsistent responses. Regardless, such responses might have implications on stress and fitness. Methodology/Principal Findings: We compared elk and cattle anti-predator responses to wolves in southwest Alberta, Canada within home ranges and livestock pastures, respectively. We deployed satellite- and GPS-telemetry collars on wolves, elk, and cattle (n = 16, 10 and 78, respectively) and measured seven prey response variables during periods of wolf presence and absence (speed, path sinuosity, time spent head-up, distance to neighboring animals, terrain ruggedness, slope and distance to forest). During independent periods of wolf presence (n = 72), individual elk increased path sinuosity (Z =-2.720, P = 0.007) and used more rugged terrain (Z =-2.856, P = 0.004) and steeper slopes (Z =-3.065, P = 0.002). For cattle, individual as well as group behavioral analyses were feasible and these indicated increased path sinuosity (Z =-2.720, P = 0.007) and decreased distance to neighbors (Z =-2.551, P = 0.011). In addition, cattle groups showed a number of behavioral changes concomitant to wolf visits, with variable direction in changes. Conclusions/Significance: Our results suggest both elk and cattle modify their behavior in relation to wolf presence, with potential energetic costs. Our study does not allow evaluating the efficacy of anti-predator behaviors, but indicates that artificial selection did not result in their absence in cattle. The costs of wolf predation on livestock are often compensated considering just the market value of the animal killed. However, society might consider refunding some additional costs (e.g., weight loss and reduced reproduction) that might be associated with the changes in cattle behaviors that we documented. © 2010 Laporte et al. Source

Man R.,Ontario Ministry of Natural Resources | Greenway K.J.,Alberta Sustainable Resource Development
New Forests | Year: 2013

Aspen (Populus tremuloides Michx.) and white spruce (Picea glauca (Moench.) Voss) were planted 0. 5 m apart in intimate mixtures in 5 × 4 m plots, with two moisture regimes-irrigation versus control-and five species compositions-pure aspen (Aw100), mixed aspen and spruce (Aw83Sw17, Aw50Sw50, Aw17Sw83), and pure spruce (Sw100), replicated six times. Fifth-year assessments indicated that irrigation increased individual tree growth (height, RCD, crown width), plot leaf area index (LAI), and wood biomass. Increased aspen composition reduced the availability of soil moisture and consequently the growth of individual trees. With increased aspen composition more growth was allocated to stem in aspen and to foliage in white spruce. Comparatively, aspen responded more to irrigation and thus their growth is more dependent on precipitation than that of spruce. Among the three growth variables assessed, height responded more to irrigation in both species. Equal mixtures and aspen-dominated mixtures in control plots had higher productivity in terms of total wood biomass in both absolute and relative terms. The implications of these findings are discussed in relation to managing aspen and white spruce mixedwood forests under increasing drought expected as a result of climate change. © 2011 Springer Science+Business Media B.V. Source

Rasmussen J.B.,University of Lethbridge | Krimmer A.N.,University of Lethbridge | Paul A.J.,Alberta Sustainable Resource Development | Hontela A.,University of Lethbridge
Journal of Fish Biology | Year: 2012

Bioelectrical impedance analysis (BIA) analysis was carried out in the field on anaesthetized Salvelinus fontinalis electrofished from a mountain stream in Alberta, Canada; the fish were then sacrificed for subsequent analysis of tissue composition. Water content was assessed by comparing wet and dry mass, and total body lipid content was measured by Soxhlet extraction with petroleum ether. A multivariate analysis of body composition and size metric against impedance measurements was carried out, and the main findings were (1) body size and related metrics were strongly related to volumetric impedance measures, as shown in several previous studies, (2) lipid content (%) and water content (%) were both well predicted by regression models whose main predictor was reactance and (3) reactance and resistance measures that were series-based produced excellent predictions of tissue composition, whereas the corresponding parallel-based models were crude. The BIA measurements are quick and easy to conduct and appear to provide excellent predictions of a number of proximate body components, without the need to kill the fish; however, more studies are required to provide improved understanding of possible effects of region, season, life stage and species on measurements. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles. Source

Macpherson L.M.,University of Alberta | Sullivan M.G.,Alberta Sustainable Resource Development | Lee Foote A.,University of Alberta | Stevens C.E.,Golder Associates
North American Journal of Fisheries Management | Year: 2012

Watercourse-crossing structures are ubiquitous anthropogenic features inthe Rocky Mountain foothills ofAlberta. We performed physical and habitat assessments at 295 watercourse-crossing sites in 15 subbasins of the Athabasca River during the summer and early fall of 2007, 2008, and 2009, sampling for fish at 110 sites (32 bridges and 78 culverts). We used bootstrapping analysis to examine how several culvert parameters (hang height, outlet plunge pool depth, water velocity, length, and slope) altered the upstream abundances of eight fish species relative to those at reference bridge sites. Physical drops at the outlet (hang heights), slope, and outlet water velocities were the most important culvert parameters shaping non-sport-fish distributions. Some culvert types (e.g., hanging culverts) acted as complete barriers to burbot Lota lota and partially impeded the movements of spoonhead sculpin Cottus ricei, suckers Catostomus spp., and minnows (family Cyprinidae). For example, at culverts with high outlet water velocities (>0.59 m/s), the upstream proportion of the total catch for burbot was 0.32 units lower than that at bridge crossings. We did not find evidence that culverts acted as barriers to the upstream passage of rainbow trout Oncorhynchus my kiss; rather, the abundances of rainbow trout significantly increased upstream of the highest-hanging, steepest, and longest culverts. One explanation may be that culverts that exclude burbot, a voracious predator, offer a competitive release for rainbow trout upstream of culverts. However, culverts had significantly higher water temperatures and silt and sand substrates upstream (versus downstream), whereas instream habitat did not differ at bridges. Given the large number of culverts that may be barriersin the Alberta foothills, our research emphasizes the need to better understand how species respond to the characteristics of culverts. Such data are needed to assist with making informed regulatory and planning decisions. © American Fisheries Society 2012. Source

Cullingham C.I.,University of Alberta | Merrill E.H.,University of Alberta | Pybus M.J.,Alberta Sustainable Resource Development | Wilson G.A.,University of Alberta | Coltman D.W.,University of Alberta
Evolutionary Applications | Year: 2011

Chronic wasting disease is a transmissible spongiform encephalopathy of cervids, similar to sheep scrapie that has only recently been detected in wild populations of white-tailed deer (Odocoileus virginianus) and mule deer (Odocoileus hemionus hemionus) in western Canada. Relatively little is known about local transmission dynamics of the disease or the potential for long-distance spread. We analysed the population genetic structure of over 2000 white-tailed deer sampled from Alberta, British Columbia, and Saskatchewan using microsatellite profiles and mtDNA sequencing to assess the relative risk of disease spread. There was very little differentiation among subpopulations and a weak trend of increasing differentiation with geographic distance. This suggests that the potential for long-distance disease spread through the dispersal of infected individuals is possible, yet the risk of spread should gradually diminish with distance from infection foci. Within subpopulations, females were more related than expected by chance (R>0) within a radius of approximately 500m. Sex-biased philopatry and social interactions among related females may facilitate local disease transmission within social groups. Local herd reduction may therefore be an effective tool for reducing the disease prevalence when implemented at the appropriate spatial scale. © 2010 Blackwell Publishing Ltd. Source

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