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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    ABSTRACT: Long-term population monitoring has become an important tool for conservation management and indicator of environmental change. In many species nest counts are used as an index of population numbers. A pilot study using double-counts in Fiordland crested penguins (Eudyptes pachyrhynchus) found that up to 12% of nests had failed following the first count, raising concerns about search-related disturbance effects and the reliability of long-term monitoring data. Here, we assess the impact of nest counts, and provide recommendations on how to reduce human disturbance effects during nest searches. In 2011, miniature temperature loggers (iButtons) were deployed into 120 nests to quantify temporary and permanent nest abandonment. Observations at nest sites allowed subsequent analysis of a range of factors potentially affecting penguin disturbance responses. In almost a third of all nests both first and second searches caused temporary nest abandonment that lasted up to 4.5 h, creating considerable predation opportunities. To reduce the likelihood of nest abandonment, counts are best conducted during the second half of the incubation period when nests are attended by single, well-established adults. Steep nesting areas proved suboptimal for long-term monitoring. Actual nest failure rates were low in 2011 (about 2% per search) and not all failures were immediately related to search disturbance. Hence, double-counts may be used in Fiordland crested penguins to improve nest count reliability as long as predation pressure is low and field protocols are adapted to minimise disturbance impact of nest searches. We show that well-designed research projects can inform and improve management decisions. For gathering reliable long-term population data, we encourage the reassessment of best-practice protocols to minimise monitoring-related disturbance effects.
    New Zealand Journal of Ecology 04/2015; 39(2). · 1.09 Impact Factor
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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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    ABSTRACT: Habitat loss and fragmentation inevitably cause biodiversity decline, a major concern for the conservation of endangered species. Primates are of particular interest, because they are highly vulnerable to forest fragmentation. In this study, we investigated faecal glucocorticoid measurements (FGCM), an indicator of physiological stress, in an endemic and IUCN-endangered monkey species inhabiting forest blocks in the Udzungwa Mountains in south-central Tanzania. The Udzungwa red colobus (Procolobus gordonorum) is threatened by hunting, and habitat degradation and loss due to agricultural expansion. They are highly folivorous, more abundant at lower elevations, but able to persist in extremely small forest blocks. We collected faecal samples in four forest blocks that differed in size, level of human impact (hunting and past logging activities) and ecological factors to examine the potential influence on stress hormone output. Across all four forests, we did not find any clear effect on FGCM levels of the variables considered, apart from elevation. Red colobus had higher FGCM levels at lower elevations, where their seemingly optimal habitat occurs, but concomitantly where greater human disturbance is found. Although our results should be interpreted with caution and confirmed with further study, we suggest that this species is not negatively influenced by a moderate level of human activity, consistent with ecological modelling data.
    African Zoology 04/2015; 50(1):23-30. DOI:10.1080/15627020.2015.1021163 · 0.85 Impact Factor
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    • "Indeed, many studies have provided evidence that human disturbance can have negative consequences for wild populations. For example, reproductive success in Humboldt penguins was found to decline at sites frequently visited by tourists (Ellenberg et al., 2006), travel from ice to sea was disrupted resulting in increased energetic cost of the commute in Emperor penguins when tourists were within 200 m of the birds (Burger and Gochfeld, 2007) and breeding success and fledging weights were reduced in yelloweyed penguins at sites where tourism was unregulated (Ellenberg et al., 2007). On the other hand, some studies suggest that penguins can habituate to the presence of humans in the wild. "
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    ABSTRACT: Multiple studies have shown that human disturbance can have negative impacts on wild penguin populations. Penguins in zoos may also be susceptible to negative impacts from humans, but this has not previously been investigated. We examined the visitor effect on a group of 25 little penguins, Eudyptula minor, by randomly imposing two treatments: 1) no visitor contact, which was achieved by closing the penguin exhibit on study days and 2) exposure to visitors, with the penguin exhibit open as usual. Treatments were imposed for 1-day periods, with five replicates of each treatment (total of 10 study days). Instantaneous point sampling and continuous sampling were used to record penguin behaviour including proximity to visitor viewing area, surface swimming, diving, vigilance, visibility, resting and intra-group aggression during a total of 3 h on each of the 10 study days. When exposed to visitors, penguins showed increased levels of aggression (P = 0.02), huddling (P = 0.049) and behaviours indicative of avoidance of visitors including increased time spent positioned behind enclosure features (P = 0.024) and increased distance from the visitor viewing area (P = 0.002). These behavioural results suggest that the presence of visitors or some aspect of visitor behaviour may have been fear-provoking for these penguins. To generalize beyond this group of animals and this enclosure requires further research.
    Applied Animal Behaviour Science 04/2015; 168. DOI:10.1016/j.applanim.2015.04.007 · 1.63 Impact Factor
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