Effects of humans on behaviour of wildlife exceed those of natural predators in a landscape of fear

• Published in: PloS one 2012-11, Vol.7 (11), p.e50611-e50611
• Main Authors: Ciuti, Simone, Northrup, Joseph M, Muhly, Tyler B, Simi, Silvia, Musiani, Marco, Pitt, Justin A, Boyce, Mark S
• Format: Article
• Language: English
• Subjects: Animal behavior; Animals; Arousal; Automobiles; Beef cattle; Biology; Breeding success; Canidae; Cervus elaphus; Comparative analysis; Conservation; Costs; Disturbance; Ecology; Ecosystems; Elk; Environmental factors; Environmental protection; Fear; Feeding; Females; Fitness; Foraging behavior; Foraging habitats; Habitats; Herbivory - physiology; Hiking; Human Activities - statistics & numerical data; Human behavior; Human factors; Human influences; Humans; Hunting; Land use; National parks; Odocoileus; Population; Predation; Predators; Predatory Behavior; Public lands; Reproduction; Reproductive fitness; Reproductive status; Roads; Roads & highways; Ruminants - psychology; Studies; Time Factors; Traffic models; Transportation; Veterinary Science; Vigilance; Wildlife; Wildlife conservation; Wildlife habitats
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0050611

Human disturbance can influence wildlife behaviour, which can have implications for wildlife populations. For example, wildlife may be more vigilant near human disturbance, resulting in decreased forage intake and reduced reproductive success. We measured the effects of human activities compared to predator and other environmental factors on the behaviour of elk (Cervus elaphus Linnaeus 1758) in a human-dominated landscape in Alberta, Canada. We collected year-round behavioural data of elk across a range of human disturbances. We estimated linear mixed models of elk behaviour and found that human factors (land-use type, traffic and distance from roads) and elk herd size accounted for more than 80% of variability in elk vigilance. Elk decreased their feeding time when closer to roads, and road traffic volumes of at least 1 vehicle every 2 hours induced elk to switch into a more vigilant behavioural mode with a subsequent loss in feeding time. Other environmental factors, thought crucial in shaping vigilance behaviour in elk (natural predators, reproductive status of females), were not important. The highest levels of vigilance were recorded on public lands where hunting and motorized recreational activities were cumulative compared to the national park during summer, which had the lowest levels of vigilance. In a human-dominated landscape, effects of human disturbance on elk behaviour exceed those of habitat and natural predators. Humans trigger increased vigilance and decreased foraging in elk. However, it is not just the number of people but also the type of human activity that influences elk behaviour (e.g. hiking vs. hunting). Quantifying the actual fitness costs of human disturbance remains a challenge in field studies but should be a primary focus for future researches. Some species are much more likely to be disturbed by humans than by non-human predators: for these species, quantifying human disturbance may be the highest priority for conservation.