Oduor Sandy, Gichuki Nathaniel N, Brown Janine L, Parker Jenna, Kimata Dennis, Murray Suzan, Goldenberg Shifra Z, Schutgens Maurice, Wittemyer George
Department of Biology, University of Nairobi, PO Box 30197-00100, Nairobi, Kenya.
Department of Reproductive Biology, Smithsonian Conservation Biology Institute, Front Royal, VA 22630, USA.
Conserv Physiol. 2024 Aug 2;12(1):coae051. doi: 10.1093/conphys/coae051. eCollection 2024.
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.
非洲草原象种群数量下降的一个关键驱动因素是栖息地丧失以及相关的人象冲突。然而，大象对这些压力的生理反应在很大程度上尚不清楚。为了填补这一知识空白，我们评估了粪便糖皮质激素代谢物（fGCM）浓度作为肾上腺活动的指标，以及粪便甲状腺代谢物（fT3）浓度作为代谢活动的指标，这些指标与土地利用、牲畜密度和人类景观改造相关，同时控制季节性和初级生产力（使用归一化植被指数测量）的影响。我们的最佳拟合模型发现，在旱季、人类改造指数值较高的地区以及农牧业活动和牲畜较多的地区，fGCM浓度会升高。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、农牧业景观、人类活动较高的地点以及没有牲畜的地区，fT3浓度较高。这项研究突出了大象在利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，这些结果有助于更好地解释人象界面处的大象行为，并有助于制定更具洞察力的保护策略。
