| Summary: | Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Wild animal populations are continuously subjected to periodic disturbances by environmental and anthropogenic causes. Thereby, in this doctoral thesis, we carried out different investigations to study the behavioural and physiological stress responses of several small mammal species to different environmental and human factors. Behavioral responses to predation risk, interspecific competition and human disturbances were analyzed by live trapping. For analyzing the correspondent physiological stress responses, fresh faeces of individuals captured were collected during each experimental situation and the quantification of faecal corticosterone metabolites (FCM) as indicator of the adrenal activity was performed in the laboratory by an enzyme immunoassay. Results showed that wood mice (Apodemus sylvaticus) individuals responded to predation risk situations by recognizing and avoiding their main known predators in the study areas (they did not respond to the faecal odour of an unknown one) and also avoiding increased moonlight. Besides, foraging activity and food intake vary in relation to the risky situations but no physiological stress response was found due to the increase in predation risk. In relation to the interspecific competition with wild ungulates, Algerian mice (Mus spretus) abundances were higher inside areas where ungulates were not present being habitat selection influenced by greater vegetation cover. Increased FCM levels inside areas without ungulates were due to the higher mice abundance whereas in the grazed areas depended on the higher soil compaction caused by ungulates. Finally, we studied whether human disturbances through agricultural practices and motorways affected small mammal populations. We found a smaller number of common voles (Microtus arvalis) inhabiting inside crops, additionally, individuals captured inside crops showed higher FCM concentrations. In relation to the ...
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