Brain Function Research Group, School of Physiology, Faculty of Health Sciences, University of the Witwatersrand, Parktown 2193, South Africa
Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa.
J Exp Biol. 2021 Feb 24;224(Pt Suppl 1):jeb238113. doi: 10.1242/jeb.238113.
Mammals in drylands are facing not only increasing heat loads but also reduced water and food availability as a result of climate change. Insufficient water results in suppression of evaporative cooling and therefore increases in body core temperature on hot days, while lack of food reduces the capacity to maintain body core temperature on cold nights. Both food and water shortage will narrow the prescriptive zone, the ambient temperature range over which body core temperature is held relatively constant, which will lead to increased risk of physiological malfunction and death. Behavioural modifications, such as shifting activity between night and day or seeking thermally buffered microclimates, may allow individuals to remain within the prescriptive zone, but can incur costs, such as reduced foraging or increased competition or predation, with consequences for fitness. Body size will play a major role in predicting response patterns, but identifying all the factors that will contribute to how well dryland mammals facing water and food shortage will cope with increasing heat loads requires a better understanding of the sensitivities and responses of mammals exposed to the direct and indirect effects of climate change.
干旱地区的哺乳动物不仅面临着日益增加的热量负荷，还面临着气候变化导致的水资源和食物减少。水分不足会抑制蒸发冷却，因此在炎热的天气里会导致体温升高，而食物不足则会降低在寒冷的夜晚维持体温的能力。食物和水的短缺都会缩小规定区域，即身体核心温度相对稳定的环境温度范围，这将增加生理功能障碍和死亡的风险。行为上的改变，如在夜间和白天之间转换活动或寻找具有热缓冲作用的小气候，可能使个体能够留在规定区域内，但这可能会产生代价，例如减少觅食或增加竞争或被捕食的风险，从而对适应性产生影响。体型将在预测反应模式方面发挥主要作用，但要确定所有有助于干旱地区哺乳动物在面临水和食物短缺时应对日益增加的热量负荷的因素，需要更好地了解暴露于气候变化直接和间接影响下的哺乳动物的敏感性和反应。
