Hair cortisol concentration in Siberian flying squirrels is unrelated to landscape and social factors

Andrea Santangeli,Chiara Morosinotto,Ralf Wistbacka,Aura Raulo

doi:10.1007/s00114-019-1624-y

Abstract

Intact ecosystems are being lost or modified worldwide, and many animal species are now forced to live in altered landscapes. A large amount of scientific studies have focused on understanding direct effects of habitat alterations on species occurrence, abundance, breeding success, and other life history aspects. Much less attention has been placed on understanding how habitat alterations impact on the physiology of species, e.g., via elevated chronic stress when living in an altered landscape. Here, we quantify the effects of individual age and sex, as well as effects of landscape and social factors on chronic stress of an endangered forest specialist species, the Siberian flying squirrel Pteromys volans. We collected hair samples over 2 years from across 192 flying squirrels and quantified their chronic stress response via cortisol concentrations. We then ran statistical models to relate cortisol concentrations with landscape and social factors. We show that cortisol concentrations in flying squirrels are neither affected by habitat amount and connectivity, nor by the density of conspecifics in the area. We however found that cortisol concentration was higher in adults than in pups, and in males compared with females. Lack of an effect of environmental factors on cortisol concentrations may indicate low physiological sensitivity to alterations in the surrounding environment, possibly due to low densities of predators that could induce stress in the study area. Further research should focus on possible effects of varying predator densities, alone and in interaction with landscape features, in shaping chronic stress of this and other species.

Highlights

IntroductionIn order to tackle and reverse these drivers of threat, it is crucial to have a deep understanding of the processes and mechanisms linking species and individual responses to rapid environmental changes
The loss, fragmentation, and degradation of habitats are major drivers of the current biodiversity crisis and species extinctionCommunicated by: Matthias Waltert Electronic supplementary material The online version of this article contains supplementary material, which is available to authorized users.globally (Pimm et al 1995)
Hair cortisol concentrations in flying squirrels significantly vary by sex and age of individuals, being higher in adults than in pups, and in males compared to females (Table 1; Fig. 2)

Summary

Introduction

In order to tackle and reverse these drivers of threat, it is crucial to have a deep understanding of the processes and mechanisms linking species and individual responses to rapid environmental changes. Such understanding is still very limited for several species, and this lack of knowledge strongly reduces the effectiveness of conservation actions (Sutherland et al 2004). Vertebrates typically cope with noxious temporary stimuli by initiating a stress response (Sheriff et al 2011) If such a stress response is activated and maintained over time due to a permanent stimulus, e.g., a change in the environment that

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