title: A spatial theory for characterizing predator-multiprey interactions in heterogeneous landscapes.
abstract: Trophic interactions in multiprey systems can be largely determined by prey distributions. Yet, classic predator-prey models assume spatially homogeneous interactions between predators and prey. We developed a spatially informed theory that predicts how habitat heterogeneity alters the landscape-scale distribution of mortality risk of prey from predation, and hence the nature of predator interactions in multiprey systems. The theoretical model is a spatially explicit, multiprey functional response in which species-specific advection-diffusion models account for the response of individual prey to habitat edges. The model demonstrates that distinct responses of alternative prey species can alter the consequences of conspecific aggregation, from increasing safety to increasing predation risk. Observations of threatened boreal caribou, moose and grey wolf interacting over 378 181 km(2) of human-managed boreal forest support this principle. This empirically supported theory demonstrates how distinct responses of apparent competitors to landscape heterogeneity, including to human disturbances, can reverse density dependence in fitness correlates.
authors.affiliation: Chaire de Recherche Industrielle CRSNG-Université Laval en Sylviculture et Faune, Département de Biologie, Université Laval, Québec, G1V 0A6, Canada daniel.fortin@bio.ulaval.ca.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fortin
authors.affiliation: GIREF, Chaire de Recherche Industrielle du CRSNG en Calcul Scientifique, Département de Mathématiques et de Statistique, Université Laval, Québec, G1V 0A6, Canada Faculty of Science, University of Ontario Institute of Technology, 2000 Simcoe Street North, Oshawa, Ontario, Canada.
authors.forename: Pietro-Luciano
authors.initials: PL
authors.lastname: Buono
authors.affiliation: Yale School of Forestry and Environmental Studies, 370 Prospect Street, New Haven, CT 06511, USA.
authors.forename: Oswald J
authors.initials: OJ
authors.lastname: Schmitz
authors.affiliation: Chaire de Recherche Industrielle CRSNG-Université Laval en Sylviculture et Faune, Département de Biologie, Université Laval, Québec, G1V 0A6, Canada.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Courbin
authors.affiliation: Chaire de Recherche Industrielle CRSNG-Université Laval en Sylviculture et Faune, Département de Biologie, Université Laval, Québec, G1V 0A6, Canada.
authors.forename: Chrystel
authors.initials: C
authors.lastname: Losier
authors.affiliation: Département de Biologie, Chimie et Géographie, Centre d'Études Nordiques, Université du Québec à Rimouski, Rimouski, Canada.
authors.forename: Martin-Hugues
authors.initials: MH
authors.lastname: St-Laurent
authors.affiliation: Chaire de Recherche Industrielle CRSNG-Université du Québec en Abitibi-Témiscamingue et Université du Québec à Montréal en aménagement forestier durable, Département des Sciences Biologiques, Université du Québec à Montréal, Montréal, Canada.
authors.forename: Pierre
authors.initials: P
authors.lastname: Drapeau
authors.affiliation: Direction de la gestion de la faune de la Côte-Nord, Ministère des Forêts, de la Faune et des Parcs (MFFP), Baie-Comeau, Canada.
authors.forename: Sandra
authors.initials: S
authors.lastname: Heppell
authors.affiliation: Direction de la gestion de la faune du Saguenay-Lac-St-Jean, MFFP, Jonquière, Canada.
authors.forename: Claude
authors.initials: C
authors.lastname: Dussault
authors.affiliation: Direction de la gestion de la faune du Nord-du-Québec, MFFP, Chibougamau, Canada.
authors.forename: Vincent
authors.initials: V
authors.lastname: Brodeur
authors.affiliation: Direction de la faune terrestre et de l'avifaune, MFFP, Québec, Canada.
authors.forename: Julien
authors.initials: J
authors.lastname: Mainguy
mesh_terms: D000818:Animals; D002170:Canada; D003670:Deer / Q000502:physiology*; D020387:Food Chain; D008954:Models, Biological; D011235:Predatory Behavior; D012053:Reindeer / Q000502:physiology; D019596:Wolves / Q000502:physiology*
keywords: animal movement; apparent competition; caribou; density dependence; mortality risk; predator–prey interaction