Elevated hormonal stress response and reduced reproductive output in Yellow-eyed penguins exposed to unregulated tourism

Ellenberg, Ursula; Setiawan, Alvin N.; Cree, Alison; Houston, David M.; Seddon, Philip J.

doi:10.1016/j.ygcen.2007.02.022

Cited by 211 publications

(175 citation statements)

References 42 publications

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“…For example, individuals of yellow-eyed penguins (Megadyptes antipodes) appear to be sensitized to tourists. Yet, birds found in high-impact tourist areas have higher stress-induced corticosterone levels and lower reproductive success than birds at sites with limited tourist impact [87]. Chicks did not habituate as well as adults to tourist activity [88].…”

Section: Hormones and Potential Responses To Global Changementioning

confidence: 87%

Hormonally mediated maternal effects, individual strategy and global change

Meylan¹,

Miles

Clobert

2012

Phil. Trans. R. Soc. B

102

108

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A challenge to ecologists and evolutionary biologists is predicting organismal responses to the anticipated changes to global ecosystems through climate change. Most evidence suggests that short-term global change may involve increasing occurrences of extreme events, therefore the immediate response of individuals will be determined by physiological capacities and life-history adaptations to cope with extreme environmental conditions. Here, we consider the role of hormones and maternal effects in determining the persistence of species in altered environments. Hormones, specifically steroids, are critical for patterning the behaviour and morphology of parents and their offspring. Hence, steroids have a pervasive influence on multiple aspects of the offspring phenotype over its lifespan. Stress hormones, e.g. glucocorticoids, modulate and perturb phenotypes both early in development and later into adulthood. Females exposed to abiotic stressors during reproduction may alter the phenotypes by manipulation of hormones to the embryos. Thus, hormone-mediated maternal effects, which generate phenotypic plasticity, may be one avenue for coping with global change. Variation in exposure to hormones during development influences both the propensity to disperse, which alters metapopulation dynamics, and population dynamics, by affecting either recruitment to the population or subsequent life-history characteristics of the offspring. We suggest that hormones may be an informative index to the potential for populations to adapt to changing environments.

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Section: Hormones and Potential Responses To Global Changementioning

confidence: 87%

Hormonally mediated maternal effects, individual strategy and global change

Meylan¹,

Miles

Clobert

2012

Phil. Trans. R. Soc. B

102

108

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“…Indeed, Ellenberg et al (2007) reported that male yellow-eyed penguins (Megadyptes antipodes) had higher baseline plasma corticosterone concentrations than females on average, but the difference was not statistically significant. However, sex differences in baseline concentrations of plasma corticosterone have been detected previously in Magellanic penguins (Spheniscus magellanicus) (Hood et al, 1998), with males having higher levels than females.…”

Section: Discussionmentioning

confidence: 99%

“…This point, of the inadequacy of a single plasma sample for making sound inferences about baseline steroid hormone concentrations, has been outlined previously (von Holst, 1998;Harper & Austad, 2000;Goymann, 2005;Palme et al, 2005), yet studies still report baseline steroid hormone concentrations based on single plasma samples (e.g. Vleck et al, 2000;Walker et al, 2005b;Raouf et al, 2006;Ellenberg et al, 2007).…”

Section: Discussionmentioning

confidence: 99%

Comparing plasma and faecal measures of steroid hormones in Adelie penguins Pygoscelis adeliae

et al. 2009

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Abstract. Physiological measurements of both stress and sex hormones are often used to estimate the consequences of natural or human-induced change in ecological studies of various animals. Different methods of hormone measurement exist, potentially explaining variation in results across studies; methods should be cross-validated to ensure they correlate.We directly compared faecal and plasma hormone measurements for the first time in a wild free-living species, the Adelie penguin (Pygoscelis adeliae). Blood and faecal samples were simultaneously collected from individual penguins for comparison, and assayed for testosterone and corticosterone (or their metabolites). Sex differences and variability within each measure, and correlation of values across measures were compared. For both hormones, plasma samples showed greater variation than faecal samples. Males had higher mean corticosterone concentrations than females, but the difference was only statistically significant in faecal samples. Plasma testosterone, but not faecal testosterone, was significantly higher in males than females. Correlation between sample types was poor overall, and weaker in females than in males, perhaps because measures from plasma represent hormones that are both free and bound to globulins, whereas measures from faeces represent only the free portion. Faecal samples also represent a cumulative measure of hormones over time, as opposed to a plasma 'snapshot' concentration. Our data indicate that faecal sampling appears more suitable for assessing baseline hormone concentrations, while plasma sampling may best define immediate responses to environmental events. Consequently, future studies should ensure they select the most appropriate matrix and method of hormone measurement to answer their research questions.

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“…For example, ecotourism studies have shown that Gentoo (Pygoscelis papua) and Magellanic (Spheniscus megellanicus) penguins, which show little fear of humans, exhibit minimal reproductive suppression at popular ecotourist sites. In contrast, fearful species such as Humboldt and yellow-eyed penguins (Megadyptes antipodes) exhibit impaired breeding [25,[37][38][39]. New comparative research has tested such associations statistically using large, multi-species databases.…”

Section: Boldnessmentioning

confidence: 99%

“…However, this increasingly plausible idea remains untested. Captive birds would make ideal subjects for exploring this further, given the new wealth of comparative data on their fear of humans in the wild [36][37][38][39][40][41].…”

Section: Boldnessmentioning

confidence: 99%