Factors limiting marine connectivity at a species' range edge - the case of the pink sea fan, Eunicella verrucosa

限制物种分布范围边缘海洋连通性的因素——以粉红海扇 Eunicella verrucosa 为例

• 批准号: 2784014
• 金额: --
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2784014
• 关键词: Factors; limiting; marine; connectivity; species

The pink sea fan, Eunicella verrucosa, is IUCN red-listed and is a protected species in UK waters. It is listed as a Protected Feature, a key factor in the designation of many of the MCZs designated in southwest England in 2013 and 2016. An understanding of the diversity and connectivity of this species is essential for both conservation of the species and the designation of further candidate MCZs (Natural England, 2016). We anticipate that this research will inform on both these key factors. The proposed project will investigate the extent of oceanographic pathways and barriers to gene flow, e.g. due to residual currents such as tidal mixing fronts and coastal/estuarine circulation patterns, and the role of selection in driving genetic differences between populations of pink sea fan at the northern limit of its range in southwest Britain. E. verrucosa is a broadcast spawner, with larvae reliant on oceanic currents for dispersal, and yet, to date, very little is known about the basic biology of this species, with little or no knowledge of its retention time in the water column or its ability to deal with thermal stress. Accordingly, we will undertake modelling and aquarium studies to begin to explore key biological factors that might be contributing to the lack of recruitment into these range edge populations. Obvious avenues for investigation include: heat stress, factors affecting spawning time, spawning duration, survival in the water column and pelagic larval duration. As these data become available these can subsequently be parameterised into our oceanographic models. High quality physical (currents, temperatures) and biological (e.g. population distributions, larval behaviour) data will be used to ground-truth the models, and a sensitivity framework will be designed to set the dispersal/connectivity results within uncertainties based on natural variability and model parameterisations. We hold at Exeter an extensive selection of sea fan tissue samples collected from across the species' range in the northeast Atlantic and the western Mediterranean and, critical to this proposal, we have now obtained permission to work with NRW staff at the Skomer Marine Reserve in Pembrokeshire, Wales, to take tissue samples from new recruits which have recently settled within the Skomer Marine Reserve. A key objective will be to establish whether the low level of recruitment of new sea fans at Skomer is due to connectivity, selection (possibly temperature, esp., minimum winter temperature), or whether (or to what extent) the Allee effect is acting, whereby the population density of mature adult fans is now so low (few fans, widely spaced) that the chances of gametes finding each other are reduced below an as yet unknown critical threshold. Findings for Skomer will be compared with those obtained at Lundy, a site at a similar latitude, but with potentially more robust in-water connectivity to major populations of pink sea fan in north and west Cornwall and the Isles of Scilly. We will use a molecular technique known as RAD-seq to identify single nucleotide polymorphism (SNPs) loci associated with particular geographical regions and/or with particular selection pressures. Our on-going project (Exeter) has recently finalised the screening of several thousand SNPs from across the pink sea fan genome - a panel of the most discriminating SNPs will be selected based on their ability to discriminate populations of interest (based on FST). In summary, the project offers a unique, trans-disciplinary research training for a postgraduate student with opportunities to gain experience in molecular genetics, oceanographic modelling and aquarium manipulations of sensitive marine organisims, generating results that will feed directly into UK marine policy through our CASE partner, Natural England, and our associate partner, Natural Resources Wales. Such a mix should deliver a highly skilled and employable young researcher.

粉红海扇（Eunicella verrucosa）被列入世界自然保护联盟红色名录，是英国水域的受保护物种。它被列为受保护特征，是 2013 年和 2016 年在英格兰西南部指定的许多 MCZ 指定的关键因素。了解该物种的多样性和连通性对于保护该物种和指定更多候选 MCZ 至关重要（自然英格兰，2016 年）。我们预计这项研究将为这两个关键因素提供信息。拟议的项目将调查海洋路径的范围和基因流动的障碍，例如由于潮汐混合锋和沿海/河口环流模式等残余流，以及选择在驱动英国西南部粉红海扇分布范围北端种群之间遗传差异方面的作用。 E. verrucosa 是一种广播产卵者，其幼虫依靠洋流进行传播，然而，迄今为止，人们对该物种的基本生物学知之甚少，对其在水柱中的停留时间或其应对热应激的能力知之甚少或一无所知。因此，我们将进行建模和水族馆研究，以开始探索可能导致这些范围边缘种群缺乏招募的关键生物学因素。明显的调查途径包括：热应激、影响产卵时间的因素、产卵持续时间、水体中的存活率和中上层幼虫持续时间。当这些数据可用时，这些数据随后可以被参数化到我们的海洋学模型中。高质量的物理（水流、温度）和生物（例如种群分布、幼虫行为）数据将用于验证模型，并且将设计敏感性框架，以根据自然变异和模型参数化在不确定性范围内设置扩散/连通性结果。我们在埃克塞特保存了大量从东北大西洋和西地中海的海扇分布范围内收集的海扇组织样本，对这一提议至关重要的是，我们现在已获得与威尔士彭布罗克郡斯科默海洋保护区的北威州工作人员合作的许可，从最近在斯科默海洋保护区定居的新海扇身上采集组织样本。一个关键目标是确定 Skomer 新海迷招募水平低是否是由于连通性、选择（可能是温度，特别是冬季最低温度），或者是否（或在多大程度上）阿利效应正在发挥作用，即成熟成年海扇的人口密度现在如此之低（海扇很少，分布广泛），以至于配子找到彼此的机会降低到了未知的临界阈值以下。斯科默的研究结果将与在伦迪获得的结果进行比较，伦迪是一个纬度相似的地点，但与康沃尔郡北部和西部以及锡利群岛的粉红海扇主要种群之间的水内联系可能更强大。我们将使用称为 RAD-seq 的分子技术来识别与特定地理区域和/或特定选择压力相关的单核苷酸多态性 (SNP) 位点。我们正在进行的项目（埃克塞特）最近完成了对粉红海扇基因组中数千个 SNP 的筛选 - 将根据其区分感兴趣群体的能力（基于 FST）选择一组最具辨别力的 SNP。总之，该项目为研究生提供了独特的跨学科研究培训，让他们有机会获得敏感海洋生物的分子遗传学、海洋学建模和水族馆操作方面的经验，产生的结果将通过我们的 CASE 合作伙伴 Natural England 和我们的合作伙伴 Natural Resources Wales 直接纳入英国海洋政策。这样的组合应该会培养出一名技术精湛、就业能力强的年轻研究人员。