PDF《wolf》

Spatio-temporal dynamics in the response of woodland caribou and moose to the passage of grey wolf Guillaume Latombe1 *, Daniel Fortin2 and Lael Parrott1 ?

1 Geography Department, Complex Systems Laboratory, University of Montreal, C.

P. 6128, Succursale Centre-ville Montr eal, Montr eal, QC, H3C 3J7,Canada;

and

2 Biology Department, Sylviculture and Wildlife Research Chair CRSNG-Laval University, Laval University,

1045 Av. de la M edecine, Pavillon Alexandre-Vachon, Qu ebec, QC, G1V 0A6,Canada Summary 1. Predators impact prey populations not only by consuming individuals, but also by altering their behaviours. These nonlethal effects can in?uence food web properties as much as lethal effects. The mechanisms of nonlethal effects include chronic and temporary anti-predator behaviours, the nature of which depends on the spatial dynamics of predators and the range over which prey perceive risk. 2. The relation between chronic and ephemeral responses to risk determines predatorCprey interactions, with consequences that can ripple across the food web. Nonetheless, few studies have quanti?ed the spatio-temporal scales over which prey respond to predation threat, and how this response varies with habitat features. 3. We evaluated the reaction of radio-collared caribou and moose to the passage of radio-col- lared wolves, by considering changes in movement characteristics during winter and summer. We used an optimization algorithm to identify the rate at which the impact of prior passage of wolves decreases over time and with the predator'

s distance. 4. The spatial and temporal scales of anti-predator responses varied with prey species and season. Caribou and moose displayed four types of behaviour following the passage of wolves: lack of response, increased selection of safe land cover types, decreased selection of risky cover types and increased selection of food-rich forest stands. For example, moose increased their avoidance of open conifer stands with lichen in summer, which are selected by wolves in this season. Also in winter, caribou increased their selection of conifer stands with lichen for nearly

10 days following a wolf'

s passage. This stronger selection for food- rich patches could indicate that the recent passage of wolves informs caribou on the current predator distribution and reveals the rate at which this information become less reliable over time. 5. Caribou and moose used anti-predator responses that combine both long- and short-term behavioural adjustments. The spatial game between wolves and their prey involves complex and nonlinear mechanisms that vary between species and seasons. A comprehensive assess- ment of risk effects on ecosystem dynamics thus requires the characterization of chronic and temporary anti-predator behaviours. Key-words: behavioural response race, ecology of fear, GPS, habitat selection, predation, predatorCprey spatial game, space race, step selection functions *Correspondence author. E-mail: guillaume.latombe@umontreal.ca ? Present address: Earth &

Environmental Sciences and Biology Units, The University of British Columbia, Okanagan Campus,

3333 University Way, Kelowna, BC, V1V 1V7,Canada ?

2013 The Authors. Journal of Animal Ecology ?

2013 British Ecological Society Journal of Animal Ecology 2014, 83, 185C198 doi: 10.1111/1365-2656.12108 Introduction Anti-predator behaviours are commonly observed amongst prey populations. These behaviours can be costly, however, because they generally take away time from other potentially ?tness-enhancing behaviours (Brown &