Integrative assessment of immunity, health-state, growth and survival of Magellanic penguin chicks in a colony exposed to ecotourism

CUMPLIDO M; D'AMICO VL; BERTELLOTTI M; ATENCIO M; DINSMORE S; PALACIOS MG

SCIENCE OF THE TOTAL ENVIRONMENT

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2023

0048-9697

Accumulating reports of negative impacts of tourist activities on wildlife emphasize theimportance of closely monitoring focal populations. Although some effects are readily noticed,more subtle ones such as changes in physiological functions of individuals might go overlooked.Based on evidence of altered physiology associated with ecotourism on Magellanic penguinsSpheniscus magellanicus, here we performed an integrated assessment using a diversephysiological toolkit together with more traditional fitness-related measures to better understandmechanisms and potential consequences. Chicks exposed to tourism showed altered immunecondition and elevated flea prevalence, reinforcing previous findings. Tourism-exposed female,but not male, chicks also showed reduced hematocrit and plasma protein levels, providingevidence of sex-specific susceptibility. Physiological alterations detected in tourism-exposedyoung (week 1-2) chicks were maintained and the effect on flea infestation increased during thestudy period (week 4-5 of post-hatch). Despite the effects on physiology, these did not seem totranslate into immediate fitness costs. No detectable effects of tourism were found on brood sexratios, chick growth and body condition, and survival until week 5-6 post-hatch. No effects weredetected on reproductive output and only a marginal effect on nest survival despite previousreports of tourism-associated alterations in stress indices of adults. This disconnection couldresult if the physiological changes are not strong enough to impact the measured fitness-relatedtraits and/or only show impacts later in the brooding cycle or even after chick emancipation fromtheir parents. In this respect, a potential link between our results and the previously documentedfemale-biased juvenile mortality in this colony deserves consideration. Integrative assessmentsof anthropogenic impacts on wildlife should include understanding of physiological mechanismsand individual-level responses to enable the development or tailoring of management measuresfor effective conservation of exposed populations.