Borthwick Zachary, Quiring Katrin, Griffith Simon C, Leu Stephan T
School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia Australia.
School of Natural Sciences Macquarie University Sydney New South Wales Australia.
Ecol Evol. 2024 Feb 13;14(2):e10996. doi: 10.1002/ece3.10996. eCollection 2024 Feb.
Extreme weather conditions, like heatwave events, are becoming more frequent with climate change. Animals often modify their behaviour to cope with environmental changes and extremes. During heat stress conditions, individuals change their spatial behaviour and increase the use of shaded areas to assist with thermoregulation. Here, we suggest that for social species, these behavioural changes and ambient conditions have the potential to influence an individual's position in its social network, and the social network structure as a whole. We investigated whether heat stress conditions (quantified through the temperature humidity index) and the resulting use of shaded areas, influence the social network structure and an individual's connectivity in it. We studied this in free-ranging sheep in the arid zone of Australia, GPS-tracking all 48 individuals in a flock. When heat stress conditions worsened, individuals spent more time in the shade and the network was more connected (higher density) and less structured (lower modularity). Furthermore, we then identified the behavioural change that drove the altered network structure and showed that an individual's shade use behaviour affected its social connectivity. Interestingly, individuals with intermediate shade use were most strongly connected (degree, strength, betweenness), indicating their importance for the connectivity of the social network during heat stress conditions. Heat stress conditions, which are predicted to increase in severity and frequency due to climate change, influence resource use within the ecological environment. Importantly, our study shows that these heat stress conditions also affect the animal's social environment through the changed social network structure. Ultimately, this could have further flow on effects for social foraging and individual health since social structure drives information and disease transmission.
极端天气状况，如热浪事件，随着气候变化正变得愈发频繁。动物常常会改变其行为以应对环境变化和极端情况。在热应激条件下，个体改变其空间行为，并增加对阴凉区域的利用以辅助体温调节。在此，我们认为对于群居物种而言，这些行为变化和环境条件有可能影响个体在其社会网络中的位置以及整个社会网络结构。我们调查了热应激条件（通过温湿度指数量化）以及由此导致的对阴凉区域的利用，是否会影响社会网络结构以及个体在其中的连通性。我们在澳大利亚干旱地区的自由放养绵羊群体中进行了此项研究，通过GPS追踪了一群共48只个体。当热应激条件恶化时，个体在阴凉处停留的时间更长，网络的连通性更强（密度更高）且结构更松散（模块性更低）。此外，我们随后确定了导致网络结构改变的行为变化，并表明个体对阴凉区域的利用行为影响其社会连通性。有趣的是，中等程度利用阴凉区域的个体之间的联系最为紧密（度数、强度、介数），这表明它们在热应激条件下对社会网络连通性的重要性。由于气候变化，热应激条件预计在严重程度和发生频率上都会增加，这会影响生态环境中的资源利用。重要的是，我们的研究表明这些热应激条件还会通过改变社会网络结构来影响动物的社会环境。最终，这可能会对社会觅食和个体健康产生进一步的连锁反应，因为社会结构推动信息和疾病传播。
