Translocation of elephants in a South African savanna : studies on endocrinological changes, vocalization and feeding behaviour

Abstract

Elephants (Loxodonta africana) in southern Africa affect ecosystem processes and vegetation structure and are therefore managed, but the effects of certain management actions on stress-related behaviour in elephants are poorly understood. As an initial step, changes in glucocorticoid output, vocal communication and feeding behaviour were investigated following a translocation event in elephants in the Kruger National Park (KNP). As a prerequisite, baseline concentrations of faecal glucocorticoid metabolites (FGM) were determined for breeding herds of African elephants. No significant differences in FGM concentrations were found across age classes, but FGM concentrations were significantly higher in the dry season. To investigate the impact of translocation on adrenocortical endocrine activity, a breeding herd was moved. Faecal samples collected within 3 weeks of translocation had significantly higher FGM levels than samples collected pre-translocation. FGM levels returned to baseline concentrations after the translocated animals reached their original home range. Changes in the fundamental frequency of calls were recorded during translocation and the mean fundamental frequency levels of low-frequency vocalizations increased significantly during the time that the translocated herd spent outside their original home range. Data on the preference of elephants for woody plants were recorded during wet and dry seasons and results revealed a seasonal selection in preference and indicated that elephant herds do not have a high preference for at least some of the woody species prone to extirpation. The recorded selection at plant species level provides the basis for determining potential changes in feeding behaviour in relation to translocation, indicated by the frequency of destructive feeding modes recorded. Recordings of destructive feeding modes, although potentially useful to indicate arousal state, showed that destructive feeding did not change in relation to the monitored translocation event. The work presented in this thesis shows the utility of assessing changes in glucocorticoid levels and recorded vocalizations as non-invasive methods for objectively assessing stress responses to translocation in a breeding herd of African elephants.