Predator-mediated interactions through changes in predator home range size can lead to local prey exclusion

• Published in: Proceedings of the Royal Society B: Biological Sciences
• Main Authors: Beardsell, Andréanne, Berteaux, Dominique, Dulude-De Broin, Frédéric, Gauthier, Gilles, Clermont, Jeanne, Gravel, Dominique, Bêty, Joël
• Other Authors: Canada Research Chairs, Fonds de recherche du Québec – Nature et technologies, Environment Canada, Université Laval, Polar Knowledge Canada, Kenneth M. Molson Foundation, W. Garfield Weston Foundation, ArcticNet, Natural Sciences and Engineering Research Council of Canada, International Polar Year program, Université du Québec à Rimouski, Arctic Goose Joint Venture, Northern Scientific Training Program, Canada Foundation for Innovation
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2023
• Subjects: Arctic Fox; Vulpes lagopus
• Online Access: http://dx.doi.org/10.1098/rspb.2023.1154; https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2023.1154; https://royalsocietypublishing.org/doi/full-xml/10.1098/rspb.2023.1154

The strength of indirect biotic interactions is difficult to quantify in the wild and can alter community composition. To investigate whether the presence of a prey species affects the population growth rate of another prey species, we quantified predator-mediated interaction strength using a multi-prey mechanistic model of predation and a population matrix model. Models were parametrized using behavioural, demographic and experimental data from a vertebrate community that includes the arctic fox ( Vulpes lagopus ), a predator feeding on lemmings and eggs of various species such as sandpipers and geese. We show that the positive effects of the goose colony on sandpiper nesting success (due to reduction of search time for sandpiper nests) were outweighed by the negative effect of an increase in fox density. The fox numerical response was driven by changes in home range size. As a result, the net interaction from the presence of geese was negative and could lead to local exclusion of sandpipers. Our study provides a rare empirically based model that integrates mechanistic multi-species functional responses and behavioural processes underlying the predator numerical response. This is an important step forward in our ability to quantify the consequences of predation for community structure and dynamics.