Coping with continuous human disturbance in the wild: insights from penguin heart rate response to various stressors

Vincent A Viblanc,René Groscolas,Benoit Gineste,Andrew D Smith

doi:10.1186/1472-6785-12-10

Abstract

BackgroundA central question for ecologists is the extent to which anthropogenic disturbances (e.g. tourism) might impact wildlife and affect the systems under study. From a research perspective, identifying the effects of human disturbance caused by research-related activities is crucial in order to understand and account for potential biases and derive appropriate conclusions from the data.ResultsHere, we document a case of biological adjustment to chronic human disturbance in a colonial seabird, the king penguin (Aptenodytes patagonicus), breeding on remote and protected islands of the Southern ocean. Using heart rate (HR) as a measure of the stress response, we show that, in a colony with areas exposed to the continuous presence of humans (including scientists) for over 50 years, penguins have adjusted to human disturbance and habituated to certain, but not all, types of stressors. When compared to birds breeding in relatively undisturbed areas, birds in areas of high chronic human disturbance were found to exhibit attenuated HR responses to acute anthropogenic stressors of low-intensity (i.e. sounds or human approaches) to which they had been subjected intensely over the years. However, such attenuation was not apparent for high-intensity stressors (i.e. captures for scientific research) which only a few individuals experience each year.ConclusionsHabituation to anthropogenic sounds/approaches could be an adaptation to deal with chronic innocuous stressors, and beneficial from a research perspective. Alternately, whether penguins have actually habituated to anthropogenic disturbances over time or whether human presence has driven the directional selection of human-tolerant phenotypes, remains an open question with profound ecological and conservation implications, and emphasizes the need for more knowledge on the effects of human disturbance on long-term studied populations.

Highlights

A central question for ecologists is the extent to which anthropogenic disturbances might impact wildlife and affect the systems under study
Overall, pooling all data together and controlling for stressor type by including it as a factor in the model, we found that brooders situated in an area of frequent human disturbance generally exhibited lower heart rate (HR) responses than their congeners breeding in an almost undisturbed area (LMMs; t = 4.3, p < 0.001, n = 76, N = 33 birds, and t = 2.07, p = 0.04, n = 76, N = 33 birds; for HR excess and maximum HR increase, respectively)
The smaller HR excess observed both for sounds and 10-m approaches in birds breeding in areas of frequent human disturbance were due to a smaller maximum relative increase in HR and to a much shorter duration of this increase

Summary

Introduction

A central question for ecologists is the extent to which anthropogenic disturbances (e.g. tourism) might impact wildlife and affect the systems under study. There is a need for more data in order to evaluate the impacts of anthropogenic disturbances on wildlife, especially for protected species in pristine environments. Such studies are essential because they enable to establish guidelines for the conduct of scientists towards studied species and the management of tourism and recreational activities in natural habitats [26,29,30,31,32,33,34], but especially because of their implications on the way we think about scientific experiments in the wild, and the inferences we derive from those experiments [17]

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Discussion

Conclusion