Effects of seabird nutrient inputs on the productivity of coral reef fish communities

珊瑚礁如何能够维持其巨大的大型珊瑚礁鱼类生物量一直困扰着科学家。小型的底栖（“隐底栖”）礁鱼生活迅速，幼鱼死亡，被认为是珊瑚礁生产力的重要组成部分，为食物网提供燃料。然而，隐底栖鱼类群落强烈依赖于环境条件，因此，如果它们周围的环境发生变化，它们在推动食物网生产力方面的作用可能会发生重大变化。珊瑚礁的环境条件受到海鸟群存在的巨大影响，海鸟群（通过它们的粪便）向岛屿提供源源不断的海洋营养物质，这些营养物质渗入周围的珊瑚礁。然而，海鸟的存在或不存在（通常由老鼠的存在驱动）如何影响周围珊瑚礁上的隐底栖鱼类群落，以及它们在珊瑚礁上喂养许多掠食性鱼类中的作用，目前尚不清楚。这项研究将调查海鸟是否通过隐底栖鱼类群落改变珊瑚礁食物网，以及这些变化在多大程度上是可逆的。具体来说，该项目旨在回答以下问题：1)在老鼠出没的岛屿和海鸟占主导地位的岛屿之间，隐底生物群落是否存在差异？2)这是否会影响隐底栖鱼类对大型捕食者的生产力作用？3)多隐底栖鱼类倾向于在珊瑚礁上补充自己的种群，或分布在珊瑚礁之间；4)这如何影响老鼠出没与海鸟为主的岛屿附近珊瑚礁的整体生产力？这些问题将利用隐底栖鱼类群落的实地数据收集、质谱和种群遗传学的实验室技术以及种群和种群动态分析来解决。兰开斯特大学、班戈大学和德克萨斯大学奥斯汀分校的主要研究人员将提供指导和专业发展机会，并通过研讨会、会议和实验室访问提供广泛的外部发展机会。

How coral reefs can sustain their extreme biomass of large reef fishes has continued to puzzle scientists. By living fast and dying young, small, bottom-dwelling ('cryptobenthic') reef fishes have been suggested as an important part of coral reef productivity, fuelling the foodweb. Yet, cryptobenthic fish communities are strongly dependent on environmental conditions, and as such their role in driving productivity of the foodweb may change substantially if the environment surrounding them is altered. Environmental conditions on coral reefs are dramatically influenced by the presence of seabird colonies that provide a steady influx of ocean-derived nutrients to islands (through their droppings), which leach out to surrounding coral reefs. However, how the presence or absence (typically driven by the presence of rats) of seabirds may affect cryptobenthic fish communities on surrounding reefs and their role in feeding the many predatory fishes on coral reefs is currently unknown. This study will investigate whether seabirds alter coral reef food-webs through cryptobenthic fish communities and to what extent these changes are reversible. Specifically, the project seeks to answer the following questions: 1) do cryptobenthic communities differ between rat-infested and seabird-dominatedislands?; 2) does this affect the productivity role of cryptobenthic fishes for larger predators?; 3) docryptobenthic fishes tend to replenish their own populations on a reef, or distribute among reefs?; and 4) how does this affect the overall productivity of reefs adjacent to rat-infested vs. seabird-dominated islands? The questions will be tackled using field-based data collection on cryptobenthic fish communities, laboratory techniques in mass spectrometry and population genetics, and analyses of population and community dynamics. Mentoring and professional development opportunities will be provided by leading researchers at Lancaster University, Bangor University, and the University of Texas at Austin, and extensive opportunities for external development via workshops, conferences, and lab visits will be offered.