RESEARCH PAPER
Extrinsic and intrinsic factors affecting the daily rhythms of a semiaquatic carnivore in a Mediterranean environment
 
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Dipartimento di Biologia ‘Charles Darwin’, Università “La Sapienza” di Roma, Viale dell’Università 32, 00185 Roma, Italy Current address: CIBIO/InBio – Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Vairão, 4485-661 Vairão, Portugal CEABN/InBIO, Centro de Ecologia Aplicada “Prof Baeta Neves”, Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal
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ICAAM – Mediterranean Agricultural and Environmental Sciences Institute – University of Évora, Portugal Current address: CIBIO - Biodiversity and Genetic Resources Research Center – Pólo de Évora, University of Évora, Portugal
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Dipartimento di Biologia ‘Charles Darwin’, Università “La Sapienza” di Roma, Viale dell’Università 32, 00185 Roma, Italy
Online publish date: 2018-02-22
 
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ABSTRACT:
Field research assessing the effects of both intrinsic and extrinsic factors on animal daily rhythms has been rare, particularly in carnivores and other medium-to-large mammals in hot environments (e.g., Mediterranean regions). This is a crucial knowledge gap, hindering the accurate prediction of how animals might react to widely-anticipated global environmental changes. To assess the behavioral plasticity of Mediterranean semiaquatic mammals in coping with harsh climatic conditions, we investigated the effects of intrinsic and extrinsic factors on the daily rhythms of a Mediterranean population of radio-tracked Eurasian otters (Lutra lutra). Multiple components cosinor population models revealed markedly nocturnal activity, affected by seasonality and air temperature. In particular, otters lowered their daylight activity and increased their nighttime activity during the dry season, being generally less active under higher air temperatures. Other extrinsic factors affecting otters’ daily rhythms were moon phase, habitat type and wind, whereas differences in activity patterns according to intrinsic factors were mainly related to males’ ranging behavior and females’ reproductive status. This study provided detailed and population-mean data on Lutra lutra daily rhythms, including some insights into inter-individual variation. More importantly, it showed that otters are well adapted to the dry and wet season-cycle typical of Mediterranean regions, while highlighting potential vulnerability of otters to increasing air temperatures.
CORRESPONDING AUTHOR:
Lorenzo Quaglietta   
Dipartimento di Biologia ‘Charles Darwin’, Università “La Sapienza” di Roma, Viale dell’Università 32, 00185 Roma, Italy Current address: CIBIO/InBio – Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Vairão, 4485-661 Vairão, Portugal CEABN/InBIO, Centro de Ecologia Aplicada “Prof Baeta Neves”, Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal, Tapada da Ajuda, 1349-017 Lisbon, Portugal
eISSN:1825-5272
ISSN:0394-1914