title: Spreading free-riding snow sports represent a novel serious threat for wildlife.
abstract: Stress generated by humans on wildlife by continuous development of outdoor recreational activities is of increasing concern for biodiversity conservation. Human disturbance often adds to other negative impact factors affecting the dynamics of vulnerable populations. It is not known to which extent the rapidly spreading free-riding snow sports actually elicit detrimental stress (allostatic overload) upon wildlife, nor what the potential associated fitness and survival costs are. Using a non-invasive technique, we evaluated the physiological stress response induced by free-riding snow sports on a declining bird species of Alpine ecosystems. The results of a field experiment in which radiomonitored black grouse (Tetrao tetrix) were actively flushed from their snow burrows once a day during four consecutive days showed an increase in the concentration of faecal stress hormone (corticosterone) metabolites after disturbance. A large-scale comparative analysis across the southwestern Swiss Alps indicated that birds had higher levels of these metabolites in human-disturbed versus undisturbed habitats. Disturbance by snow sport free-riders appears to elevate stress, which potentially represents a new serious threat for wildlife. The fitness and survival costs of allostatic adjustments have yet to be estimated.
authors.affiliation: Zoological Institute, Division of Conservation Biology, University of Bern, Baltzerstrasse 6, 3012 Bern, Switzerland. raphael.arlettaz@nat.unibe.ch
authors.forename: Raphaël
authors.initials: R
authors.lastname: Arlettaz
authors.forename: Patrick
authors.initials: P
authors.lastname: Patthey
authors.forename: Marjana
authors.initials: M
authors.lastname: Baltic
authors.forename: Thomas
authors.initials: T
authors.lastname: Leu
authors.forename: Michael
authors.initials: M
authors.lastname: Schaub
authors.forename: Rupert
authors.initials: R
authors.lastname: Palme
authors.forename: Susanne
authors.initials: S
authors.lastname: Jenni-Eiermann
mesh_terms: D000818:Animals; D044822:Biodiversity; D001715:Bird Diseases / Q000378:metabolism*; D003247:Conservation of Natural Resources; D003345:Corticosterone / Q000032:analysis; D004467:Economics; D005243:Feces / Q000737:chemistry; D046094:Galliformes; D006801:Humans; D016014:Linear Models; D038161:Snow Sports; D013312:Stress, Physiological / Q000378:metabolism / Q000662:veterinary*; D013557:Switzerland
chemical_list: D003345:Corticosterone