title: Movement responses of caribou to human-induced habitat edges lead to their aggregation near anthropogenic features.
abstract: The assessment of disturbance effects on wildlife and resulting mitigation efforts are founded on edge-effect theory. According to the classical view, the abundance of animals affected by human disturbance should increase monotonically with distance from disturbed areas to reach a maximum at remote locations. Here we show that distance-dependent movement taxis can skew abundance distributions toward disturbed areas. We develop an advection-diffusion model based on basic movement behavior commonly observed in animal populations and parameterize the model from observations on radio-collared caribou in a boreal ecosystem. The model predicts maximum abundance at 3.7 km from cutovers and roads. Consistently, aerial surveys conducted over 161,920 km(2) showed that the relative probability of caribou occurrence displays nonmonotonic changes with the distance to anthropogenic features, with a peak occurring at 4.5 km away from these features. This aggregation near disturbed areas thus provides the predators of this top-down-controlled, threatened herbivore species with specific locations to concentrate their search. The edge-effect theory developed here thus predicts that human activities should alter animal distribution and food web properties differently than anticipated from the current paradigm. Consideration of such nonmonotonic response to habitat edges may become essential to successful wildlife conservation.
authors.affiliation: Chaire de Recherche Industrielle, Conseil de recherches en sciences naturelles et en génie du Canada (CRSNG)-Université Laval en Sylviculture et Faune, Département de Biologie, Université Laval, Québec, Québec G1V 0A6 Canada. daniel.fortin@bio.ulaval.ca
authors.forename: Daniel
authors.initials: D
authors.lastname: Fortin
authors.forename: Pietro-Luciano
authors.initials: PL
authors.lastname: Buono
authors.forename: André
authors.initials: A
authors.lastname: Fortin
authors.forename: Nicolas
authors.initials: N
authors.lastname: Courbin
authors.forename: Christian
authors.initials: C
authors.lastname: Tye Gingras
authors.forename: Paul R
authors.initials: PR
authors.lastname: Moorcroft
authors.forename: Réhaume
authors.initials: R
authors.lastname: Courtois
authors.forename: Claude
authors.initials: C
authors.lastname: Dussault
mesh_terms: D063147:Animal Distribution; D000818:Animals; D017753:Ecosystem; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D011792:Quebec; D012053:Reindeer / Q000523:psychology*; D014197:Trees