Modelling coral reef connectivity in the Western Indian Ocean under climate change

气候变化下西印度洋珊瑚礁连通性建模

• 批准号: 2284948
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2284948
• 关键词: Modelling; coral; reef; connectivity; Western

Coral reefs worldwide arefacing more risks than ever before.The Intergovernmental Panel on Climate Change(IPCC)published that global ocean warming is strongest at the surface and the Indian Ocean surface temperatures have increased at a rate of0.11 C per decade, fasterthan for the Atlantic and Pacific Oceans.(Hoegh-Guldberg et al., 2014; IPCC, 2018; van Vuuren et al., 2011)The Indian Ocean warming of 0.65 C compared to 1950 -2009 exceeds the other oceans as well(Hoegh-Guldberg et al., 2014). Average live coral cover has decreased by 50 -75 % almost everywherein the last 30 -40 years(Bruno et al., 2019).This situation is predicted to get worse with future mass bleaching events (Hughes et al., 2017). A third of reef-forming coral species are considered threatened and another third as near threatened in the IUCN Red List (Bridge et al., 2020).These taxa are critical for reef resilience and complexity which form the base of healthy fish communities(Eakin et al., 2019). Coastal protection and food security under global change depend on efficient conservation management that accounts for genetic connectivity of corals under present conditions and future climate change scenarios (Graham et al., 2015; Hughes et al., 2017).Current models of coral or reef fish distribution under climate change often do not include larval dispersal which is a critical factor that influences the trajectory of reefs after a disturbance event such as bleaching(Graham et al., 2015; Magris et al., 2016).The Indian Ocean is especially heavily impacted by climate change and reefs in the Western region are essential resourcesfor some of the world's poorest communities.Currently, only three key connected reefs are under protectionand conservation focus on the other highly connectedreefs is requiredin order for them to act as stepping stones for larval and gene dispersal(Gamoyo et al., 2019). However,knowledge about coral connectivity and reef resilience under future climate scenarios in this geographical region is limited despite increasing threats and anthropogenic pressure. With further climate impacts it is vital to understand how present circulation patterns and coral and fish population dynamics might change and how this affects reef resilience and food security. Marine protected areas (MPAs)emerged as one of the key measures to support coral reefs but their success depends on how connected they are on large scales by movement of fish or larval dispersal (Crochelet et al., 2016). One of the world's largest no-take marine reserves is the British Indian Ocean Territory(BIOT) MPAin the centre of the Indian Ocean which was designated by the UK in 2010. Since the 1970s, the archipelago is uninhabited except for a US military base on the largest atoll,Diego Garcia,and thus, has no fishing pressure besides some illegal activities. Despite its protection and remote location with minimal anthropogenic impacts the reefs in the archipelago endured severe bleaching and mortality with coral cover decreasingfrom 30% to 12 %between 2012 and 2016. Acropora, one of the key ecosystem architects, showed an 86% declineand was replaced by Porites after the bleaching event. (Head et al., 2019) With its central Indian Ocean location halfway between Africa and Indonesia this large MPA could act as an important stepping stone linking the Western and Eastern Indian Ocean under global change (Robinson et al., 2017). My research aims to model coral reef connectivity under present conditions and the IPCC climate scenarios in the Western Indian Oceanand the BIOT.Knowledge on connectivity of reef-building corals can underpin observational studies and improve predictions of species distributions under climate change scenarios (Wood et al., 2014).

全球的珊瑚礁正面临着前所未有的危险。政府间气候变化专门委员会（IPCC）公布，全球海洋变暖在表层最为强烈，印度洋表层温度以每十年0.11摄氏度的速度上升，比大西洋和太平洋的速度还要快。（Hoegh-Guldberg等人，2014; IPCC，2018;货车Vuuren等人，2011)与1950 - 2009年相比，印度洋变暖0.65 C，也超过了其他海洋（Hoegh-Guldberg等人，2014年）。在过去的30 - 40年里，平均活珊瑚覆盖率几乎每年都下降50 - 75%（Bruno等人，2019).预计这种情况会随着未来的大规模漂白事件而变得更糟（Hughes等人，2017年）。在IUCN红色名录中，三分之一的造礁珊瑚物种被认为受到威胁，另外三分之一被认为接近受到威胁（Bridge等人，2020).这些分类群对于珊瑚礁的复原力和复杂性至关重要，而珊瑚礁的复原力和复杂性构成了健康鱼类群落的基础（Eakin等人，2019年）。全球变化下的沿海保护和粮食安全取决于有效的保护管理，这种管理考虑到了珊瑚在目前条件和未来气候变化情景下的遗传联系（Graham等人，2015; Hughes等人，2017).目前气候变化下珊瑚或礁鱼分布的模型通常不包括幼虫扩散，这是影响珊瑚礁在诸如漂白等干扰事件后轨迹的关键因素（Graham等人，2015; Magris等人，2016).印度洋受到气候变化的影响尤其严重，西部地区的珊瑚礁是世界上一些最贫穷社区的基本资源。目前，只有三个关键的相连珊瑚礁受到保护，需要重点保护其他高度相连的珊瑚礁，以便它们作为幼虫和基因传播的垫脚石（Gamoyo等人，2019年）。然而，尽管威胁和人为压力不断增加，但对该地理区域未来气候情景下珊瑚连通性和珊瑚礁复原力的了解有限。随着气候的进一步影响，至关重要的是要了解目前的循环模式以及珊瑚和鱼类种群动态可能如何变化，以及这如何影响珊瑚礁的复原力和粮食安全。海洋保护区（MPAs）成为支持珊瑚礁的关键措施之一，但其成功取决于它们在大规模上如何通过鱼类移动或幼虫传播而相互联系（Crochelet等人，2016年）。世界上最大的禁捕海洋保护区之一是位于印度洋中心的英属印度洋领地（毕奥）MPA，由英国于2010年指定。自20世纪70年代以来，除了最大的环礁迭戈·加西亚上的一个美国军事基地外，该群岛无人居住，因此，除了一些非法活动外，没有捕鱼压力。尽管受到保护，位置偏远，人为影响最小，但群岛的珊瑚礁遭受了严重的漂白和死亡，珊瑚覆盖率在2012年至2016年间从30%下降到12%。Acropora是生态系统的关键建筑师之一，在漂白事件后下降了86%，并被Porites取代。(Head例如，2019）由于其位于非洲和印度尼西亚之间的印度洋中部，这个大型MPA可以作为全球变化下连接西印度洋和东印度洋的重要垫脚石（罗宾逊等人，2017年）。我的研究旨在模拟目前条件下的珊瑚礁连通性，以及西印度洋和毕奥的IPCC气候情景。有关造礁珊瑚连通性的知识可以支持观测研究，并改善气候变化情景下物种分布的预测（Wood等人，2014年）。