Effects of Wolves on Elk and Cattle Behaviors: Implications for Livestock Production and Wolf Conservation

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 anti-predator 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

Locating food in a spatially heterogeneous environment: Implications for fitness of the macrodecomposer Armadillidium vulgare (Isopoda: Oniscidea)

To assess the fitness consequences of foraging on patchy resources, consumption rates, growth rates and survivorship of Armadillidium vulgare were monitored while feeding in arenas in which the spatial distribution of patches of high quality food (powdered dicotyledonous leaf litter) was varied within a matrix of low quality food (powdered grass leaf litter). Predictions from behavioural experiments that these fitness correlates would be lower when high quality food is more heterogeneously distributed in space were tested but not supported either by laboratory or field experiments. To investigate whether A. vulgare can develop the ability to relocate high quality food patches, changes in foraging behaviour, over a comparable time period to that used in the fitness experiments, were monitored in arenas in which there was a high quality food patch in a low quality matrix. A. vulgare increased its ability to relocate the position of high quality food over time. It reduced time spent in low quality food matrices and increased time spent in high quality food patches with time after the start of the experiment. When the position of a high quality food patch was moved, the time spent in the low quality food matrix increased and less time was spent in high quality food patches, compared to arenas in which the food was not moved. The fitness benefits for saprophages of developing the ability to relocate high quality patches while foraging in spatially heterogeneous environments are discussed