PDF(Pubmed)
Abstract：
A key driver of the African savannah elephant population decline is the loss of habitat and associated human-elephant conflict. Elephant physiological responses to these pressures, however, are largely unknown. To address this knowledge gap, we evaluated faecal glucocorticoid metabolite (fGCM) concentrations as an indicator of adrenal activity and faecal thyroid metabolite (fT3) concentrations as an indicator of metabolic activity in relation to land use, livestock density, and human landscape modification, while controlling for the effects of seasonality and primary productivity (measured using the normalized difference vegetation index). Our best-fit model found that fGCM concentrations to be elevated during the dry season, in areas with higher human modification index values, and those with more agropastoral activities and livestock. There was also a negative relationship between primary productivity and fGCM concentrations. We found fT3 concentrations to be higher during the wet season, in agropastoral landscapes, in locations with higher human activity, and in areas with no livestock. This study highlights how elephants balance nutritional rewards and risks in foraging decisions when using human-dominated landscapes, results that can serve to better interpret elephant behaviour at the human-wildlife interface and contribute to more insightful conservation strategies.
摘要：
非洲大草原大象数量下降的一个关键驱动因素是栖息地的丧失和相关的人象冲突。大象对这些压力的生理反应，然而,基本上是未知的。为了解决这个知识差距，我们评估了粪便糖皮质激素代谢产物（fGCM）浓度作为肾上腺活动的指标和粪便甲状腺代谢产物（fT3）浓度作为与土地利用相关的代谢活性的指标，家畜密度,和人文景观改造，同时控制季节性和初级生产力的影响（使用归一化植被指数衡量）。我们的最佳拟合模型发现fGCM浓度在旱季会升高，在人类修饰指数值较高的地区，以及那些有更多农牧活动和牲畜的人。初级生产力与fGCM浓度之间也存在负相关关系。我们发现在雨季fT3浓度更高，在农牧景观中，在人类活动较高的地方，在没有牲畜的地区。这项研究强调了大象在使用人类主导的景观时如何在觅食决策中平衡营养回报和风险，结果可以更好地解释大象在人类-野生动物界面的行为，并有助于更有见地的保护策略。
