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.

粉红色的海扇，Eunicella verrucosa，是世界自然保护联盟的红色名录，是英国沃茨的保护物种。它被列为受保护的特征，这是2013年和2016年在英格兰西南部指定的许多MCZ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（Natural England，2016）。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学途径的程度和基因流的障碍，例如，由于残余电流，如潮汐混合锋和沿海/河口环流模式，以及选择的作用，在驱动遗传差异的粉红色海扇在北方限制其范围在英国西南部的人口。E.多疣鱼是一种传播产卵鱼，其幼虫依靠洋流传播，然而，迄今为止，人们对这一物种的基本生物学知之甚少，对其在水柱中的停留时间或应对热应力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的研究，开始探索关键的生物因素，可能有助于缺乏招聘到这些范围边缘人口。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、在水柱中的存活和浮游幼虫持续时间。随着这些数据变得可用，随后可以将其参数化到我们的海洋学模型中。将使用高质量的物理（海流、温度）和生物（例如种群分布、幼虫行为）数据来确定模型的真实性，并将设计一个敏感性框架，以便在基于自然变异和模型参数化的不确定性范围内确定扩散/连通性结果。我们在埃克塞特举行了广泛的选择海扇组织样本收集从整个物种的范围在东北大西洋和地中海西部，这一建议的关键，我们现在已经获得许可，与北威州的工作人员在斯科默海洋保护区在彭布罗克郡，威尔士，采取组织样本的新兵最近定居在斯科默海洋保护区。一个关键目标将是确定斯科默新海扇的低水平招募是否是由于连通性，选择（可能是温度，特别是，最低冬季温度），或者Allee效应是否（或在多大程度上）起作用，即成熟成年粉丝的人口密度现在如此之低（粉丝很少，分布广泛），以至于配子找到对方的机会降低到一个未知的临界阈值以下。Skomer的研究结果将与在Lundy获得的结果进行比较，Lundy是一个纬度相似的地点，但与康沃尔北部和西部以及锡利群岛的粉红色海扇主要种群的水中连接可能更强大。我们将使用一种称为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）基因座。我们正在进行的项目（埃克塞特）最近完成了从粉红色海扇基因组中筛选数千个SNP的工作-将根据它们区分感兴趣人群的能力（基于FST）选择一组最具鉴别力的SNP。总之，该项目为研究生提供了独特的跨学科研究培训，有机会获得分子遗传学，海洋学建模和敏感海洋生物水族馆操作的经验，产生的结果将通过我们的CASE合作伙伴，自然英格兰和我们的合作伙伴，自然资源威尔士直接进入英国海洋政策。这样的组合应该提供一个高技能和就业的年轻研究人员。