Les hommes ont oublié cette vérité. Mais tu ne dois pas l'oublier, dit le renard. Tu deviens responsable pour toujours de ce que tu as apprivoisé.
Le Petit Prince, chap. 21

Friday, 2 January 2015

Intraguild competition among mesopredators

Garvey, P. M., Glen, A. S., & Pech, R. P. (2014). Foraging Ermine Avoid Risk: behavioural responses of a mesopredator to its interspecific competitors in a mammalian guild. Biological Invasions, 1-13.
Interference competition between predators strongly influences the structure and composition of ecological communities. These interactions are usually asymmetrical as larger predators dominate in aggressive encounters. Smaller predators are forced to balance the conflicting demands of obtaining food while reducing the risk of a confrontation. We tested the behavioural responses of 16 wild captured stoats (Mustela erminea) to the presence of a feral cat (Felis catus) and a ferret (Mustela furo), which we refer to as “larger predators” due to their superior body size. Stoats were released individually into an outdoor arena and nocturnal activities were recorded on infra-red video cameras. On treatment nights, one of the larger predators was placed inside a segregated holding cage on one side of the arena, while an empty cage was placed on the opposite side as a control. A stoat’s daily food allocation was divided into two equal portions, one placed in front of each holding cage to form a food “patch”. Stoats’ perception of risk was assessed by comparing behaviour in the risky patch (close to the caged predator) versus the safe patch (close to the empty cage). Stoats harvested less food at the risky patch. They avoided the area containing the larger predator, both spatially and temporally, and increased vigilance at the risky patch. The results show that stoats alter their foraging behaviour due to perceived interference competition when they encounter larger predators. Understanding trophic interactions between invasive species will help to inform conservation decisions and maximise the effectiveness of management intervention.

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