Data from: Tick exposure and extreme climate events impact survival and threaten the persistence of a long-lived lizard

1. Assessing the impacts of multiple, often synergistic, stressors on the population dynamics of long-lived species is becoming increasingly important due to recent and future global change. 2. Tiliqua rugosa (sleepy lizard) is a long-lived skink (>30 years) that is adapted to survive in semi-arid environments with varying levels of parasite exposure and highly seasonal food availability. We used an exhaustive database of 30-years of capture-mark-recapture records to quantify the impacts of both parasite exposure and environmental conditions on the lizard's survival rates and long-term population dynamics. 3. Lizard abundance was relatively stable throughout the study period; however there were changing patterns in adult and juvenile apparent survival rates, driven by spatial and temporal variation in levels of tick exposure and temporal variation in environmental conditions. Extreme weather events during the winter and spring seasons were identified as important environmental drivers of survival. 4. Climate models predict a dramatic increase in the frequency of extreme hot and dry winter and spring seasons in our South Australian study region; from a contemporary probability of 0.17 up to 0.47 - 0.83 in 2080 depending on the emissions scenario. Our stochastic population model projections showed that these future climatic conditions will induce a decline in the abundance of this long-lived reptile of up to 67% within 30 years from 2080, under worst case scenario modelling. 5. The results have broad implications for future work investigating the drivers of population dynamics and persistence. We highlight the importance of long-term datasets and accounting for synergistic impacts between multiple stressors. We show that predicted increases in the frequency of extreme climate events have the potential to considerably and negatively influence a long-lived species, which might previously have been assumed to be resilient to environmental perturbations.

1. 鉴于近期与未来的全球变化，探究多重（通常兼具协同效应）胁迫因子对长寿物种种群动态的影响，其重要性正与日俱增。
2. 钝尾石龙子（Tiliqua rugosa，sleepy lizard）是一种寿命可达30年以上的石龙子（skink），适应于存在不同程度寄生虫暴露、食物可获得性呈强季节性变化的半干旱环境。我们利用一套涵盖30年标记重捕（capture-mark-recapture）记录的完整数据库，量化了寄生虫暴露与环境条件对该蜥蜴存活率及长期种群动态的影响。
3. 整个研究周期内，该蜥蜴的种群丰度相对稳定，但成体与幼体的表观存活率（apparent survival rates）变化模式存在差异，该差异由蜱虫暴露水平的时空变异与环境条件的时间变异共同驱动。研究明确冬、春两季的极端天气事件是影响存活率的关键环境因子。
4. 气候模型（climate models）预测，我们位于南澳大利亚的研究区域内，冬、春两季极端炎热干旱事件的发生频率将大幅攀升：当前发生概率为0.17，而到2080年，依据不同排放情景（emissions scenario），该概率将升至0.47至0.83不等。我们的随机种群模型（stochastic population model）预测结果显示，在最坏情景建模框架下，这些未来气候条件将导致这种长寿爬行动物的种群丰度在2080年后的30年内下降至多67%。
5. 本研究结果对未来探究种群动态与存续驱动因子的相关工作具有广泛启示价值。我们着重强调了长期数据集的重要性，以及需纳入多重胁迫因子间的协同效应。研究表明，预测的极端气候事件频率上升，可能会对此前被认为可抵御环境扰动的长寿物种产生显著的负面影响。