Ecotourism effects on health and immunity of Magellanic penguins at two reproductive colonies with disparate touristic regimes and population trends.

Maria G Palacios,Verónica L D’Amico,Marcelo Bertellotti,Steven Cooke

doi:10.1093/conphys/coy060

Maria G Palacios, Verónica L D’Amico + Show 2 more

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https://doi.org/10.1093/conphys/coy060

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Abstract

Negative effects of ecotourism on wildlife are rising worldwide. Conservation physiology can play a major role in protecting wildlife by providing early alerts on changes in the status of individuals exposed to tourist activities. We measured an integrated set of immune and health-state indices to evaluate the effects of ecotourism on Magellanic penguins (Spheniscus magellanicus). We studied two reproductive colonies that differed in the intensity of tourism and population trends: Punta Tombo (higher tourism intensity, declining population) and San Lorenzo (lower tourism intensity, growing population). Within each colony, we compared individuals from an area that was exposed to tourists and a control area where tourism was excluded. Adult penguins exposed to tourism at Punta Tombo, but not at San Lorenzo, showed physiological alterations indicative of chronic stress (higher heterophil to lymphocyte ratios) and parasitic infection (elevated heterophil and eosinophil counts). Penguin chicks exposed to tourism at Punta Tombo, but not at San Lorenzo, also showed physiological alterations indicative of poor immune and general-health condition: lower humoral innate immunity, haematocrit, and glucose levels and higher inflammatory responses likely due to increased prevalence of fleas. Our results indicate that individuals of a declining population exposed to high levels of tourism express physiological indicators of chronic stress and poor health that could make adults and juveniles vulnerable to disease. These effects are expressed despite a long history of exposure and behavioural habituation to human visitation. In contrast, individuals of a growing population exposed to more recent and lower levels of tourism showed no effect. Our study demonstrates how a diverse physiological toolkit within a conservation physiology approach can provide important information for a better comprehension of anthropogenic effects on wild animals in our changing world.

Highlights

Population declines and extinctions of wildlife are occurring globally as a consequence of human activity (Dirzo et al, 2014; McCauley et al, 2015)
We present a study in Magellanic penguins Spheniscus magellanicus (Fig. 1) subject to ecotourist visitation that illustrates the advantages of a conservation physiology approach using a diverse physiological toolkit, reinforcing findings in other wildlife species (e.g. French et al, 2010, marine iguanas; Semeniuk et al, 2009, stingrays)
Glucose levels were significantly higher in males than females in both colonies and total eosinophil counts were significantly higher in females than in males in San Lorenzo (Supplementary data)

Summary

Introduction

Population declines and extinctions of wildlife are occurring globally as a consequence of human activity (Dirzo et al, 2014; McCauley et al, 2015). Ecotourism, or nature-based tourism, is among the fastest growing human activities in many wilderness areas worldwide (Scheyvens, 1999). Conservation physiology can play a key role in this respect and physiological indicators are becoming increasingly important for determining anthropogenic effects on wild animals (Cooke et al, 2013; Madliger et al, 2016). Assessment of stress hormone levels has been a common and valuable tool in conservation physiology; a lack of consensus on the interpretation of observed patterns in wild animals (Madliger and Love, 2014) highlights the necessity of assessing other relevant physiological functions (e.g. immunological, haematological, nutritional, metabolic) in studies of anthropogenic effects on wildlife (Geffroy et al, 2017; Madliger et al, 2016)

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