The Irish Damselfly: identifying population genetic structure and optimising habitat management for an iconic Irish species

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How the structure of a fragmented landscape influences the dynamics and persistence of a species is one of the most important questions in conservation1. Where individuals can disperse between fragments a metapopulation can result, and the subsequent patchy population structure and colonization-extinction processes can complicate decisions regarding conservation priorities. Key parameters are not only the effective population (Ne) below which the population is not viable, but there will also be critical thresholds for landscape structure2. In addition to the ecological and environmental factors which influence the viability of populations living in fragmented landscapes there are also genetic factors caused by small populations sizes and restricted geneflow. The Odonata (dragonflies and damselflies) are among the most endangered freshwater faunal taxa. Of the seven Coenagrionid damselflies that bred in the UK a hundred years ago, two are now extinct, while three of the remaining five have highly restricted distributions. One of these, the Irish Damselfly or Irish/Crescent Bluet (Coenagrion lunulatum) is found in colonies in low nutrient status wetlands, small lakes, fens and cutover bogs, and so naturally exhibits a patchy population structure. The species is IUCN listed as Vulnerable in Ireland, and is thought to be in decline, with eutrophication, habitat loss and in the longer term, climate change being the most significant threats. Previous work has shown that small unenriched lakes with beds of floating vegetation and an absence of fish are important factors for population occurrence3, and while the number of viable colonies in Ireland is currently unknown, surveys support the theory that the populations function as a metapopulation (Dragonfly Ireland 2000-2004 and Dragonfly Ireland 2019-2024). In addition, to the metapopulation structure within Ireland, the species also has an interesting international distribution; due to its geographical position and geological history, Ireland typically has fewer species present compared to Britain and Continental Europe. However, the Irish Damselfly is a rare exception to this as it is found in Ireland, but not throughout Britain, and the remainder of its distribution covers northern Europe and as far east as China. Within main European populations, it occurs in Finland, the Netherlands, and France. This project will have three main components: 1) To determine the phylogenetic relationship of the Irish Damselfly to the other populations across Europe 2) To investigate the species population genetics (connectivity, effective population size, levels of inbreeding, etc.) within Ireland3) To develop integrative models combining meta-population dynamics and habitat suitability informed by genetic connectivity measures, with a goal of informing conservation actions.It is anticipated that this project will involve International field-work with partners in Finland and France.The project offers outstanding training opportunities in genetics, genomics, bioinformatics, evolutionary analyses and a range of ecological modelling techniques, coupled with the programme of broad core and generic skills development that is central to the Quadrat DTP training programme. The student will become part of a dynamic and vibrant multidisciplinary postgraduate community, and have the opportunity to make a major contribution to our understanding of fundamental issues in biogeography, evolutionary biology, and freshwater ecology.