Data from: Parameters used in the endotherm biophysical model for each species

Climate change threatens biodiversity by compromising the ability to
balance energy and water, influencing animal behaviour, species
interactions, distribution, and ultimately survival. Predicting climate
change effects on thermal physiology is complicated by interspecific
variation in thermal tolerance limits, thermoregulatory behaviour, and
heterogenous thermal landscapes. We develop an approach for assessing
thermal vulnerability for endotherms by incorporating behaviour and
microsite data into a biophysical model. We parameterised the model using
species-specific functional traits and published behavioural data on
hotter (maximum daily temperature, Tmax > 35 °C) and cooler days
(Tmax < 35 °C). Incorporating continuous time-activity focal
observations of behaviour into the biophysical approach reveals that the
three insectivorous birds modelled here are at greater risk of lethal
hyperthermia than dehydration under climate change, contrary to previous
thermal risk assessments. Southern yellow-billed hornbills (Tockus
leucomelas), southern pied babblers (Turdoides bicolor), and southern
fiscals (Lanius collaris) are predicted to experience a risk of lethal
hyperthermia on ~ 24, 65, and 40 more d y-1, respectively, in 2100
relative to current conditions. Maintaining water balance may also become
increasingly challenging. Babblers are predicted to experience a 57 %
increase (to ~186 d yr-1) in exposure to conditions associated with net
negative 24-hour water balance in the absence of drinking, with ~ 86 of
those days associated with a risk of lethal dehydration. Hornbills and
fiscals are predicted to experience ~ 84 and 100 d y-1 respectively
associated with net negative 24-h water balance, with ≤ 20 of those days
associated with a risk of lethal dehydration. Integrating continuous
time-activity focal data is vital to understand and predict thermal
challenges animals likely experience. We provide a comprehensive thermal
risk assessment and emphasise the importance of thermoregulatory and
drinking behaviour for endotherm persistence in the coming decades.

气候变化会破坏生物的能量与水分平衡能力，影响动物行为、物种互作、分布格局，并最终威胁其生存，从而对生物多样性造成威胁。由于物种间热耐受极限、体温调节行为存在差异，且热环境具有异质性，因此预测气候变化对动物热生理的影响颇具挑战。本研究将行为与微生境数据纳入生物物理模型（biophysical model），开发了一套评估恒温动物（endotherm）热脆弱性的方法。本研究利用物种特异性功能性状，以及已发表的高温（日最高温，Tmax＞35℃）与低温（Tmax＜35℃）条件下的行为数据，对模型进行参数化。将连续时间-活动焦点行为观测数据纳入该生物物理分析框架后发现，本研究建模的3种食虫鸟类在气候变化背景下面临的致死性体温过高风险，高于脱水风险，这与此前的热风险评估结论相悖。相较于当前气候条件，预计到2100年，南黄弯嘴犀鸟（Tockus leucomelas）、南斑鸫鹛（Turdoides bicolor）和南伯劳（Lanius collaris）每年面临致死性体温过高的天数将分别增加约24天、65天和40天。维持水分平衡的难度也将持续提升。预计南斑鸫鹛在不饮水的情况下，出现24小时净水分负平衡的天数将增加57%（达到约186天/年），其中约86天会面临致死性脱水风险。预计南黄弯嘴犀鸟和南伯劳每年出现24小时净水分负平衡的天数分别约为84天和100天，其中致死性脱水风险天数均不超过20天。整合连续时间-活动焦点观测数据，对于理解和预测动物可能面临的热胁迫至关重要。本研究提供了一套全面的热风险评估框架，并强调了体温调节与饮水行为对于恒温动物在未来数十年存续的重要性。