Levels of fecal glucocorticoid metabolites do not reflect environmental contrasts across islands in black-tailed deer (Odocoileus hemionus sitkensis) populations

Authors: Le Saout, Soizic; Massouh, Marlène; Martin, Jean-Louis; Presseault-Gauvin, Hélène; Poilvé, Eva; Côté, Steeve D.; Picot, Denis; Verheyden, Hélène
Abstract: Animals face stressful situations to which they can respond by mounting a physiological response. Few studies have compared the relative effects of two or more stressors on this response. We compared how low food abundance and hunting affected levels of fecal glucocorticoid metabolites (FGM), an indicator of stress, in Sitka black-tailed deer (Odocoileus hemionus sitkensis) on the Haida Gwaii archipelago (Canada). We monitored monthly FGM levels over a year on three islands: on two, there was no hunting but deer were exposed to increased risk of severe food depletion; and on one, deer had access to abundant food but were exposed to a few days of hunting each year. Based on the context of the study, we tentatively predicted that FGM levels would be higher in low food abundance/safe islands. We also predicted that FGM levels would be higher in winter when food is rarer, particularly in low food abundance/safe islands. The three deer populations presented similar average FGM levels and seasonal variations. Our predictions were therefore not supported. Our results rather suggested that environmental contrasts, perceived by us as large (increased risk of starvation on ELI and Kunga islands) or associated with differences in animal behavior (human avoidance on Reef island), did not lead to increased stress responses. We discuss plausible explanations, including the down-regulation of the stress response in depleted environments and the lack of stress response to low hunting pressure when behavioral responses to risk are unlikely to be costly.
Document Type: Article de recherche
Issue Date: 30 August 2016
Open Access Date: Restricted access
Document version: VoR
Permalink: http://hdl.handle.net/20.500.11794/13706
This document was published in: Mammal Research, Vol. 61 (4), 391–398 (2016)
https://doi.org/10.1007/s13364-016-0294-9
Springer
Alternative version: 10.1007/s13364-016-0294-9
Collection:Articles publiés dans des revues avec comité de lecture

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