How will Emperor Penguins Respond to Changing Ice Conditions (EPIC)?

2021年，利用卫星图像生成了南极洲帝企鹅殖民地的第一个完整清单。因此，它们的种群对气候变化的脆弱性尚不为人所知也就不足为奇了，因为只在少数地点观察到它们的种群迁移。随着南极洲对气候变暖和海洋条件的反应，海冰可能会减少，这对帝企鹅栖息地的生存能力构成了潜在的重大威胁，因为它们生活在海冰上，依靠海冰的稳定性进行繁殖和喂养。2016年至2018年期间，与南极洲周围的平均水平相比，海冰面积减少了200多万平方公里，未来海冰损失的减少表明，在目前的温室气体排放情景下，到2100年，大多数殖民地可能会濒临灭绝。然而，历史和未来的群体反应都鲜为人知。例如，预测未来行为的模型是基于在单个地点测量的繁殖因素和在13年的短时间内仅在9个地点测量的行为因素。因此，有必要提高我们对过去种群变化的理解，以及它们如何与不断变化的海冰栖息地条件联系起来，以便我们能够更好地预测气候变化下未来种群的脆弱性。虽然海冰的减少（以及帝企鹅的栖息地）在很大程度上受到气候和海洋变暖的控制，但另一个可能日益破坏海冰状况的被忽视的过程是冰山的崩解，它可以推动或导致海冰破裂，使一个海湾的海冰游离。为了应对海冰的减少，帝企鹅可能会搬到另一个海冰条件更稳定的地区，或者如果没有这样的地区，最近观察到它们自己爬上冰川。这是一个戏剧性的反应，但没有它，蚁群可能会不复存在。这种对移动的观察也仅限于少数地方研究，而由产犊引起的海冰破裂事件对帝企鹅群落的影响从未被测量过。我们的目标是了解帝企鹅群落在过去、现在和未来对不断变化的冰川和海冰条件的脆弱性。我们将利用现有的免费卫星图像档案，绘制出在南极洲61个新发现的帝企鹅聚居地过去的迁徙、海冰和冰川产冰情况。这将使我们能够确定每个殖民地的历史海冰条件是如何变化的，也将使我们能够了解过去30-40年特定冰川崩解事件的影响。我们的工作将使我们能够确定蜂群迁移到冰川上或迁移到新的海冰区域的能力是对海冰损失的一种常见反应，还是这是一种新现象。利用这些信息，我们将更好地了解殖民地对海冰变化的脆弱性。在殖民地目前出现危险的地区，我们将使用非常高分辨率的商业卫星图像来确定它们是否仍然可以作为繁殖殖民地。这一认识将用于控制和增强在未来海冰和冰川崩解条件下企鹅种群动态和繁殖成功的数值模型。特别是，当气温变暖或冰川以特定频率崩解时，我们将测试殖民地的反应。这项工作的结果对我们了解该物种及其在下个世纪的生存至关重要，它有望为在气候变化面前将帝企鹅建立为受保护物种奠定基础。

In 2021, the first full inventory of emperor penguin colonies in Antarctica was generated using satellite imagery. It is therefore not surprising that their population vulnerability to changing climate is not yet well known, with colony movements only having been observed at a small number of sites. As Antarctica responds to warming climate and ocean conditions, sea ice is likely to decline, presenting a potentially significant risk to the viability of emperor penguin colonies because they live on sea ice and rely on its stability for breeding and feeding. The extent of sea ice fell by over 2 million km2 compared to average around Antarctica between 2016 and 2018, and reductions of future sea ice loss suggest that the majority of colonies may become quasi-extinct by 2100 under current greenhouse gas emission scenarios. However, both historic and future colony responses are poorly known. For example, the models which predict future behaviour are based upon breeding factors measured at a single site and behavioural factors measured at only 9 sites over a short time period of 13 years. Thus there is a significant need to improve our understanding of past colony changes and how they link to changing sea ice habitat conditions so that we can better predict future colony vulnerability under a changing climate.Although sea ice loss (and thus emperor penguin habitat) is controlled on a large scale by warming climate and oceans, an additionally overlooked process which may be increasingly disrupting sea ice conditions is the calving of icebergs which can push, or cause the fracturing of, sea ice, leaving an embayment sea ice free. In response to the loss of sea ice, emperor penguins may move to another region where sea ice conditions are more stable, or if no such area is available, they have more recently been observed to climb onto the glaciers themselves. This is a dramatic response, but without it the colony may cease to exist. Such observations of movement are again limited to a few local studies, and the impact of calving-induced sea ice breakout events upon emperor penguin colonies has never been measured. Our aim is to understand the past, present and future vulnerability of emperor penguin colonies to changing glacier and sea ice conditions. We will use existing archives of freely-available satellite imagery to map past colony movements, sea ice and glacier calving conditions at each of the 61 newly identified emperor penguin colonies in Antarctica. This will allow us to establish how historic sea ice conditions have changed at each colony and will also allow us to understand the impact of specific glacier calving events over the last 30-40 years. Our work will allow us to determine whether colony ability to move onto glacier ice or to migrate to new sea ice areas is a common reaction to sea ice loss, or whether this is a new phenomena. Using this information, we will gain better understanding of colony vulnerability to sea ice changes. In areas where colonies currently appear at risk, we will use very high-resolution commercial satellite imagery to establish whether they remain viable as a breeding colony. This understanding will be used to control and enhance numerical models of penguin population dynamics and breeding success under future scenarios of sea ice and glacier calving conditions. In particular, as air temperatures warm or as glaciers calve at a particular frequency, we will test how colonies will respond. The outcome of this work is vitally important for our understanding of the species and its survival over the next century and it expected to form the foundation for a case to establish emperor penguins as a protected species in the face of climate change.