Elevated hormonal stress response and reduced reproductive output in Yellow-eyed penguins 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: 2.47). 05/2007; 152(1):54-63. DOI: 10.1016/j.ygcen.2007.02.022
Source: PubMed


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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    • "Clear aims and defined goals of monitoring programmes are essential to justify their implementation. As our study and others (e.g.Ellenberg et al., 2007) show, it should never be assumed that the capture and handling of animals is not stressful or significant for the individuals involved. Studies should always be conducted to understand the impacts of disturbance, preferably using both physiological and fitness metrics, so that we can refine protocols if necessary and avoid contributing to the decline of sensitive populations. "
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    • "This behaviour has also prevented contact with humans; thus, their presence is often unknown even to the people living close to the breeding colonies (Albores-Barajas et al., 2008, 2012; Massa, 2009). However, increasing human activity linked either to urban development or to tourism is having an enormous impact on breeding populations, with potentially catastrophic consequences for threatened and endangered species (Nisbet, 1981, 2000; Lishman, 1985; Culik et al., 1990; Culik and Wilson, 1991; Ellenberg et al., 2007; Seddon and Ellenberg, 2008; see also review by Carney and Sydeman, 1999). "
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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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