The Southern Ocean has been disproportionately affected by climate change and is therefore an ideal place to study the influence of changing environmental conditions on ecosystems. Changes in the demography of predator populations are indicators of broader shifts in food web structure, but long-term data are required to study these effects. Southern elephant seals (Mirounga leonina) from Macquarie Island have consistently decreased in population size while all other major populations across the Southern Ocean have recently stabilized or are increasing. Two long-term mark-recapture studies (1956–1967 and 1993–2009) have monitored this population, which provides an opportunity to investigate demographic performance over a range of climatic conditions. Using a 9-state matrix population model, we estimated climate influences on female survival by incorporating two major climatic indices into our model: The Southern Annular Mode (SAM) and the Southern Oscillation Index (SOI). Our best model included a 1 year lagged effect of SAM and an unlagged SOI as covariates. A positive relationship with SAM1 (lagged) related the previous year's SAM with juvenile survival, potentially due to changes in local prey availability surrounding Macquarie Island. The unlagged SOI had a negative effect on both juvenile and adult seals, indicating that sea ice dynamics and access to foraging grounds on the East Antarctic continental shelf could explain the different contributions of ENSO events on the survival of females in this population.

中文翻译：

---

气候对南象海豹（Mirounga leonina）数量减少的雌性生存的影响

南大洋受到气候变化的影响不成比例，因此是研究不断变化的环境条件对生态系统影响的理想场所。捕食者种群的人口结构变化是食物网结构更广泛变化的指标，但需要长期数据来研究这些影响。南象海豹（Mirounga leonina) 来自麦格理岛的人口规模持续减少，而南大洋的所有其他主要人口最近都趋于稳定或正在增加。两项长期的标记重获研究（1956-1967 和 1993-2009）监测了这一人群，这为调查一系列气候条件下的人口表现提供了机会。使用 9 状态矩阵人口模型，我们通过将两个主要气候指数纳入我们的模型来估计气候对女性生存的影响：南方环形模式 (SAM) 和南方涛动指数 (SOI)。我们最好的模型包括 SAM 的 1 年滞后效应和作为协变量的非滞后 SOI。与 SAM1（滞后）的正相关关系将前一年的 SAM 与幼鱼存活率相关联，可能是由于麦格理岛周围当地猎物供应的变化。未滞后的 SOI 对幼年海豹和成年海豹都有负面影响，表明海冰动力学和南极东部大陆架觅食地的进入可以解释 ENSO 事件对该种群中雌性海豹生存的不同贡献。