Evaluación de eventos reproductivos y estrés fisiológico en vertebrados silvestres a partir de sus excretas: evolución de una metodología no invasiva

Abstract

This aims to be a general reference document of terminology and processes associated with a noninvasive technique for the study of wildlife. But it will also summarize the historical changes that such technique has experienced throughout time. Due to the difficulties associated with their capture and manipulation, research on wild vertebrates has usually required indirect approaches. One such method is the collection of feces left by the target species on the ground, and its implementation has allowed determination of distributional ranges, abundances, diet composition and association with parasites. Adopted from veterinary and farm practices, measurement of hormone levels in feces has more recently originated the, so called, Field Endocrinology. During the last 10-15 years, this line of research has generated information on reproductive cycles, seasonal changes, behavioral associations and sex related differences in hormone levels, interactions between hierarchy status, stress and hormone levels and their effect on reproductive success and, finally, evaluation of human disturbance on animal physiology. During the last three years, however, research on the lab techniques associated with this discipline has evidenced a series of confounds resulting from sample manipulation. Since this type of research requires of both, good assay protocols as well as interesting ecological questions, creative collaboration between lab technicians and animal ecologists is urgent in countries like Mexico, where financial resources designated to investigation are so scarce.