Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; NBFC, National Biodiversity Future Center, 90133 Palermo, Italy.
Department of Life Sciences, University of Siena, Via P.A. Mattioli 4, 53100 Siena, Italy; Maremma Natural History Museum, Strada Corsini 5, 58100 Grosseto, Italy.
Sci Total Environ. 2023 May 1;871:161789. doi: 10.1016/j.scitotenv.2023.161789. Epub 2023 Jan 28.
The potential for climate change to affect animal behaviour is widely recognized, yet its possible consequences on aggressiveness are still unclear. If warming and drought limit the availability of food resources, climate change may elicit an increase of intraspecific conflicts stemming from resource competition. By measuring aggressivity indices in a group-living, herbivorous mammal (the Apennine chamois Rupicapra pyrenaica ornata) in two sites differing in habitat quality, and coupling them with estimates of plant productivity, we investigated whether harsh climatic conditions accumulated during the growing season influenced agonistic contests at feeding via vegetation-mediated effects, and their interaction with the site-specific habitat quality. We focused on females, which exhibit intra-group contest competition to access nutritious food patches. Accounting for confounding variables, we found that (1) the aggression rate between foraging individuals increased with the warming accumulated over previous weeks; (2) the probability to deliver more aggressive behaviour patterns toward contestants increased with decreasing rainfall recorded in previous weeks; (3) the effects of cumulative warming and drought on aggressivity indices occurred at time windows spanning 15-30 days, matching those found on vegetation productivity; (4) the effects of unfavourable climatic conditions via vegetation growth on aggressivity were independent of the site-specific habitat quality. Simulations conducted on our model species predict a ~50 % increase in aggression rate following the warming projected over the next 60 years. Where primary productivity will be impacted by warming and drought, our findings suggest that the anticipated climate change scenarios may trigger bottom-up consequences on intraspecific animal conflicts. This study opens the doors for a better understanding of the multifactorial origin of aggression in group-living foragers, emphasising how the escalation of agonistic contests could emerge as a novel response of animal societies to ongoing global warming.
气候变化对动物行为产生影响的可能性已得到广泛认可，但气候变化对攻击性可能产生的影响仍不清楚。如果变暖与干旱限制了食物资源的可利用性，那么气候变化可能会引发源自资源竞争的种内冲突加剧。我们通过在两个栖息地质量不同的地点测量群体生活的草食性哺乳动物（阿平宁野山羊 Rupicapra pyrenaica ornata）的攻击性指数，并将其与植物生产力的估计值相结合，研究了在生长季节中积累的恶劣气候条件是否通过植被介导的影响以及与特定地点栖息地质量的相互作用来影响进食时的争斗。我们专注于雌性，它们为了获取有营养的食物斑块而在群体内进行竞争。考虑到混杂变量，我们发现：（1）觅食个体之间的攻击率随着前几周积累的变暖而增加；（2）在之前几周降雨量减少的情况下，个体向竞争者发出更具攻击性的行为模式的可能性增加；（3）累积变暖与干旱对攻击性指数的影响发生在跨越 15-30 天的时间窗口，与植被生产力中发现的时间窗口相匹配；（4）通过植被生长对攻击性产生的不利气候条件的影响独立于特定地点的栖息地质量。对我们的模式物种进行的模拟预测，在未来 60 年内，预计变暖将导致攻击率增加约 50%。如果初级生产力将受到变暖与干旱的影响，那么我们的研究结果表明，预期的气候变化情景可能会在种内动物冲突方面引发自下而上的后果。这项研究为更好地理解群体觅食者中攻击性的多因素起源开辟了道路，强调了争斗的升级如何可能成为动物社会对持续全球变暖的一种新反应。
