Data from: Hot dogs: high ambient temperatures impact reproductive success in a tropical carnivore

Climate change imposes an urgent need to recognise and conserve the species likely to be worst affected. However, while ecologists have mostly explored indirect effects of rising ambient temperatures on temperate and polar species, physiologists have predicted direct impacts on tropical species. The African wild dog (Lycaon pictus), a tropical species, exhibits few of the traits typically used to predict climate change vulnerability. Nevertheless, we predicted that wild dog populations might be sensitive to weather conditions, because the species shows strongly seasonal reproduction across most of its geographical range. We explored associations between weather conditions, reproductive costs, and reproductive success, drawing on long-term wild dog monitoring data from sites in Botswana (20°S, 24 years), Kenya (0°N, 12 years), and Zimbabwe (20°S, 6 years). High ambient temperatures were associated with reduced foraging time, especially during the energetically costly pup-rearing period. Across all three sites, packs which reared pups at high ambient temperatures produced fewer recruits than did those rearing pups in cooler weather; at the non-seasonal Kenya site such packs also had longer inter-birth intervals. Over time, rising ambient temperatures at the (longest-monitored) Botswana site coincided with falling wild dog recruitment. Our findings suggest a direct impact of high ambient temperatures on African wild dog demography, indicating that this species, which is already globally endangered, may be highly vulnerable to climate change. This vulnerability would have been missed by simplistic trait-based assessments, highlighting the limitations of such assessments. Seasonal reproduction, which is less common at low latitudes than at higher latitudes, might be a useful indicator of climate change vulnerability among tropical species.

气候变化亟需我们识别并保护那些最易受其影响的物种。然而，生态学家多聚焦于环境温度升高对温带和极地物种的间接影响，而生理学家则预测温度升高会对热带物种产生直接作用。非洲野犬（Lycaon pictus）作为热带物种，几乎不具备常用于预测气候变化脆弱性的典型特征。尽管如此，我们仍预测非洲野犬种群可能对天气条件敏感，因为该物种在其绝大多数分布范围内均表现出极强的季节性繁殖特性。本研究基于博茨瓦纳（南纬20°，监测时长24年）、肯尼亚（北纬0°，监测时长12年）与津巴布韦（南纬20°，监测时长6年）三地的长期非洲野犬监测数据，探讨了天气条件、繁殖成本与繁殖成功率之间的关联。研究发现，环境高温与觅食时长减少存在关联，这一现象在能量消耗极高的幼崽抚育期尤为显著。在三地所有研究区域中，于高温环境下抚育幼崽的种群，其新生幼崽补充量均低于低温环境下抚育幼崽的种群；在无明显季节变化的肯尼亚研究区域，这类种群的产仔间隔也更长。随着时间推移，监测时长最长的博茨瓦纳研究区域内环境温度持续升高，与此同时非洲野犬的种群补充率持续下降。本研究结果表明，高温会对非洲野犬的种群动态产生直接影响，这意味着这一已处于全球濒危状态的物种，可能极易受到气候变化的威胁。仅基于物种特征的简单评估方法会忽略这一脆弱性，这也凸显了这类评估方式的局限性。相较于高纬度地区，低纬度地区的季节性繁殖现象较为少见，而这一特性或许可作为热带物种气候变化脆弱性的有效评估指标。