The Southern Ocean (SO) is among the regions on Earth that are undergoing regionally the fastest environmental changes. The unique ecological features of its marine life make it particularly vulnerable to the multiple effects of climate change. A network of Marine Protected Areas (MPAs) has started to be implemented in the SO to protect marine ecosystems. However, considering future predictions of the Intergovernmental Panel on Climate Change (IPCC), the relevance of current, static, MPAs may be questioned under future scenarios. In this context, the ecoregionalization approach can prove promising in identifying well-delimited regions of common species composition and environmental settings. These so-called ecoregions are expected to show similar biotic responses to environmental changes and can be used to define priority areas for the designation of new MPAs and the update of their current delimitation. In the present work, a benthic ecoregionalization of the entire SO is proposed for the first time based on abiotic environmental parameters and the distribution of echinoid fauna, a diversified and common member of Antarctic benthic ecosystems. A novel two-step approach was developed combining species distribution modeling with Random Forest and Gaussian Mixture modeling from species probabilities to define current ecoregions and predict future ecoregions under IPCC scenarios RCP 4.5 and 8.5. The ecological representativity of current and proposed MPAs of the SO is discussed with regard to the modeled benthic ecoregions. In all, 12 benthic ecoregions were determined under present conditions, they are representative of major biogeographic patterns already described. Our results show that the most dramatic changes can be expected along the Antarctic Peninsula, in East Antarctica and the sub-Antarctic islands under both IPCC scenarios. Our results advocate for a dynamic definition of MPAs, they also argue for improving the representativity of Antarctic ecoregions in proposed MPAs and support current proposals of Conservation of Antarctic Marine Living Resources for the creation of Antarctic MPAs.

中文翻译：

---

基于南大洋海胆类动物区系的底栖生态区划支持目前在 IPCC 气候变化情景下设立南极海洋保护区的建议。

南大洋 (SO) 是地球上环境变化最快的区域之一。其海洋生物独特的生态特征使其特别容易受到气候变化的多重影响。海洋保护区（MPA）网络已开始在SO中实施，以保护海洋生态系统。然而，考虑到政府间气候变化专门委员会 (IPCC) 的未来预测，当前静态海洋保护区的相关性在未来情景下可能会受到质疑。在这种情况下，生态区域化方法在确定共同物种组成和环境设置的明确界定区域方面具有广阔的前景。这些所谓的生态区预计将对环境变化表现出类似的生物反应，并可用于确定指定新海洋保护区和更新其当前划界的优先区域。在目前的工作中，首次基于非生物环境参数和海胆动物群（南极海底生态系统的多样化和共同成员）的分布提出了整个SO的底栖生态区划。开发了一种新颖的两步方法，将物种分布建模与随机森林和物种概率的高斯混合建模相结合，以定义当前生态区并预测 IPCC 情景 RCP 4.5 和 8.5 下的未来生态区。就模拟的底栖生态区而言，讨论了当前和拟议的 SO 海洋保护区的生态代表性。总之，在目前条件下确定了 12 个底栖生态区，它们代表了已经描述的主要生物地理模式。我们的结果表明，在IPCC的两种情景下，南极半岛、东南极洲和亚南极岛屿的变化预计最为剧烈。我们的研究结果主张对海洋保护区进行动态定义，还主张提高拟议海洋保护区中南极生态区的代表性，并支持当前关于建立南极海洋保护区的南极海洋生物资源保护提案。