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

Department of Zoology, University of Otago, 340 Great King St., PO Box 56, Dunedin, New Zealand.
General and Comparative Endocrinology (Impact Factor: 2.67). 05/2007; 152(1):54-63. DOI: 10.1016/j.ygcen.2007.02.022
Source: PubMed

ABSTRACT The endangered, endemic Yellow-eyed penguin (Megadyptes antipodes) is one of the flagship species for New Zealand's wildlife tourism, and recently concern has been raised that tourism-related pressures may be becoming too great. We compared two neighbouring breeding areas exposed to different levels of human disturbance. Penguins at the site exposed to unregulated tourism showed significantly lower breeding success and fledging weights than those in an area visited infrequently for monitoring purposes only. High parental baseline corticosterone concentrations correlated with lower fledgling weights at both sites. Stress-induced corticosterone concentrations were significantly higher at the tourist-exposed site, suggesting birds have been sensitized by frequent disturbance. Consequences are likely to include reduced juvenile survival and recruitment to the tourist site, while the changed hormonal stress responses may ultimately have an effect on adult fitness and survival. For maintenance of attractive Yellow-eyed penguin-viewing destinations we recommend that tourists stay out of breeding areas and disturbance at penguin landing beaches is reduced.

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    • "road kill, bycatch) may be immediately apparent; however, subtle and accumulating effects of human disturbance on susceptibility to disease, fertility, and life expectancy are currently not well understood. Human disturbance can alter hormonal stress response (Walker et al. 2005; Ellenberg et al. 2007) as well as energy budgets of adult birds (Ellenberg et al. 2013); reduce breeding success, fledgling weights, and subsequent first-year survival (McClung et al. 2004; Ellenberg et al. 2006, 2007); and defer prospecting pairs from establishing a nest in disturbed habitats (Hockey & Hallinan 1981). Stressful events may redirect an individual's behaviour towards survival rather than reproduction (Watanuki et al. 1993) consequently leading to temporary or even permanent nest abandonment (Wingfield et al. 1997). "
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    • "While short-term elevations in GCs may be adaptive, by facilitating individuals to escape from life-threatening situations (Wingfield and Ramenofsky 1999; Sapolsky et al. 2000), increased production of GCs for long periods may have detrimental effects on individual fitness and population viability (Blas et al. 2007; Ellenberg et al. 2007; Bonier et al. 2009) by inhibiting growth, suppressing the immune system or inhibiting reproductive function (Sapolsky and Pulsinelli 1985). Although sometimes questioned (Busch and Hayward 2009; Boonstra 2013), faecal GC measurements (FGCM) have been recently used in ecological and conservation studies as indices of physiological stress to monitor the impact of environmental changes, both natural and anthropogenic (Thiel et al. 2008; Busch and Hayward 2009). "
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    • "Wildlife may perceive humans as potential predators and elicit different antipredator responses (e.g., Beale and Monaghan 2004). Exposure to human activities can modify behavior, physiological status, and ultimately affect the fitness of disturbed animals (Arlettaz et al. 2007; Barja et al. 2007; Ellenberg et al. 2007). In fact, the recently rising intensity and variety of human leisure activities could increase the encounter rate between humans and wild animals and, therefore, their potential negative impact on wildlife (Steven et al. 2011). "
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