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The European sardine (Sardina pilchardus) is under intense fishing pressure and exhibits distributional/abundance shifts linked to environmental change. The current understanding of population demographics needed for sustainable management is uncertain due to concerns that previous genetic studies lacked resolution and limited sampling of sardine north of the Bay of Biscay. To address these issues, we performed mtDNA sequencing and genome wide SNP analysis of samples collected across the Bay of Biscay, Celtic Sea, English Channel and North Sea. The complete SNP data reported a lack of structure throughout the sampled area compatible with high gene flow. A consensus suite of positive outlier SNPs was identified which reported a significant correlation with geographical distance with the largest differentiation between the southern Bay of Biscay and North Sea samples which also reported a significant mtDNA ΦST. While the roles of dispersal limitation and environmental heterogeneity underpinning this require further study, this adds to growing evidence that selection is influencing sardine population structure against a background of high gene flow. The results indicate that while there may be a level of demographic independence between North Sea and South Biscay sardine, the current delimitation of central (Biscay) and northern (Channel and Celtic Sea) operational stocks may misrepresent connectivity between the Biscay and Channel. The North Sea sample exhibited markedly lower mtDNA and nuclear variation than other samples. As sardine have only recently invaded the North Sea such reduced genetic variation is compatible with predictions for peripheral leading‐edge populations but contrasts with patterns for other small pelagic species and emphasises the need to consider species‐specific genetic structure in ecosystem‐based management. Nascent management of the North Sea sardine fishery must ensure that current low levels of genetic diversity are not eroded further as this may decrease the species adaptive potential and inhibit its expansion. [ABSTRACT FROM AUTHOR]

Tomicus piniperda is a common pest of pine trees responsible for significant economic damage. Although the impact of T. piniperda on forestry is likely to increase in the future due to climate change, little is known about its dispersal within the United Kingdom (UK) or between continental Europe and the UK.This study addressed these knowledge gaps using mitochondrial and microsatellite DNA markers.Mitochondrial DNA revealed high levels of genetic diversity as previously reported for this species across Europe. Nuclear DNA diversity revealed two geographically incoherent groups (Scotland, Wales, Belgium and the Netherlands vs. England and Switzerland). These genetic patterns likely reflect a combination of historical gene flow, anthropogenic introduction and restricted contemporary gene flow between the UK and Europe.Significant structure was found among UK samples suggesting T. piniperda might not disperse extensively between pine stands. This differs from widespread gene flow across continental Europe and may be due to the low percentage of land covered by forests in the UK in addition to the high fragmentation of its forest cover.Genetic variation was higher among the Scottish samples compared to those from more southern clines, suggesting the potential proximity of Scotland to a Pleistocene glacial refuge for T. piniperda. [ABSTRACT FROM AUTHOR]

Octopus cyanea (Gray, 1849), abundant in the South‐West Indian Ocean (SWIO), constitutes a vital resource for both subsistence and commercial fisheries. However, despite this socioeconomic importance, and recent indications of overfishing, little is known about the population structure of O. cyanea in the region. To inform sustainable management strategies, this study assessed the spatio‐temporal population structure and genetic variability of O. cyanea at 20 sites in the SWIO (Kenya, Tanzania, Mozambique, Madagascar, Mauritius, Rodrigues, and the Seychelle Islands) by complementary analysis of mitochondrial DNA (mtDNA) noncoding region (NCR) sequences and microsatellite markers. MtDNA analysis revealed a shallow phylogeny across the region, with demographic tests suggesting historic population fluctuations that could be linked to glacial cycles. Contrary to expectations, NCR variation was comparable to other mtDNA regions, indicating that the NCR is not a hypervariable region. Both nuclear and mtDNA marker types revealed a lack of genetic structure compatible with high gene flow throughout the region. As adults are sedentary, this gene flow likely reflects connectivity by paralarval dispersal. All samples reported heterozygote deficits, which, given the overall absence of structure, likely reflect ephemeral larval recruitment variability. Levels of mtDNA and nuclear variability were similar at all locations and congruent with those previously reported for harvested Octopodidae, implying resilience to genetic erosion by drift, providing current stock sizes are maintained. However, as O. cyanea stocks in the SWIO represent a single, highly connected population, fisheries may benefit from additional management measures, such as rotational closures aligned with paralarval ecology and spanning geopolitical boundaries. [ABSTRACT FROM AUTHOR]

Bark-feeding and wood-boring insect pests can have significant negative impacts on conifers and wood production. The damage they cause is expected to increase in the future due to climate change and the growth of international trade. This study employed DNA barcoding of beetle juveniles (Coleoptera) sampled from standing trap trees and cut log piles at regular intervals over a 2-yr period to monitor the beetle community dynamics and associated environmental factors. Tree species was found to have a major influence on beetle communities, most strikingly at the start of early decay stages. Lower species diversity was reported from standing trap tree samples compared to log pile samples, likely due to higher residual defences in dying and recently dead trees. While the species identified from standing trap trees are more likely to be a threat to the forestry sector, the species found in the log piles are more likely to be beneficial due to their high abundance and their ability to compete with pests for breeding substrate. The analysis of beetles collected inside trees revealed additional information on ontogenetic niches and host preferences beyond that acquired solely from flight interception trap data. Our results offer insights on community composition and dynamics of bark-feeding and wood-boring insect species in Welsh conifer forests and provide resources for monitoring and management of potential pest species. [ABSTRACT FROM AUTHOR]

Two sister species of horse mackerel (Trachurus trachurus and T. capensis) are described that are intensively harvested in East Atlantic waters. To address long‐standing uncertainties as to their respective geographical ranges, overlap and intraspecific population structure this study combined genetic (mitochondrial DNA and microsatellite) analysis and targeted sampling of the hitherto understudied West African coast. mtDNA revealed two reciprocally monophyletic clades corresponding to each species with interspecies nuclear differentiation supported by FST values. The T. trachurus clade was found across the north‐east Atlantic down to Ghana but was absent from Angolan and South African samples. The T. capensis clade was found only in South Africa, Angola and a single Ghanaian individual. This pattern suggests that both species may overlap in the waters around Ghana. The potential for cryptic hybridization and/or indiscriminate harvesting of both species in the region is discussed. For T. capensis mtDNA supports high gene flow across the Benguela upwelling system, which fits with the species' ecology. The data add to evidence of a lack of significant genetic structure throughout the range of T. trachurus though the assumption of demographic panmixia is cautioned against. For both species, resolution of stock recruitment heterogeneity relevant to fishery management, as well as potential hybridization, will require more powerful genomic analyses. [ABSTRACT FROM AUTHOR]

Understanding demographic processes over multiple spatial scales is vital for the optimization of conservation/management strategies, particularly for commercially harvested taxa such as the brown crab (Cancer pagurus L). Brown crab population genetic structure was investigated at (i) a local scale within the Irish Sea, which included comparisons with the Lundy No Take Zone (NTZ) and (ii) across the NE Atlantic. The results indicate that the brown crab does not exhibit strong spatial structure either within the Irish Sea or at the regional level, suggesting high gene flow within and among the Irish Sea, English Channel and North Sea. Comparisons between the Lundy NTZ and harvested areas revealed similarly high levels of genetic diversity. An intriguing result was that the Lundy NTZ sample exhibited a degree of genetic patchiness (ephemeral geographically unpatterned differentiation) which may indicate elevated recruitment skews within the NTZ. Overall, the results support the view that brown crabs within the sampled area belong to a single genetically panmictic stock and that if breeding stock sizes are maintained genetic drift will not be strong enough to reduce neutral genetic diversity. The highly connected nature of this species requires international cooperation for sustainable management, an important component of which will be the application of more powerful population genomic approaches to assess finer scale aspects of stock structure as well drivers of genetic patchiness reported for the species. This is a timely consideration in light of potential future misalignments between biological and geopolitical stock boundaries in the Irish Sea following Brexit. [ABSTRACT FROM AUTHOR]

Climate change is driving the redistribution of species at a global scale and documenting and predicting species' responses to warming is a principal focus of contemporary ecology. When interpreting and predicting their responses to warming, species are generally treated as single homogenous physiological units. However, local adaptation and phenotypic plasticity can result in intraspecific differences in thermal niche. Therefore, population loss may also not only occur from trailing edges. In species with low dispersal capacity this will have profound impacts for the species as a whole, as local population loss will not be offset by immigration of warm tolerant individuals. Recent evidence from terrestrial forests has shown that incorporation of intraspecific variation in thermal niche is vital to accurately predicting species responses to warming. However, marine macrophytes (i.e. seagrasses and seaweeds) that form some of the world's most productive and diverse ecosystems have not been examined in the same context. We conducted a literature review to determine how common intraspecific variation in thermal physiology is in marine macrophytes. We find that 90% of studies identified (n = 42) found clear differences in thermal niche between geographically separated populations. Therefore, non‐trailing edge populations may also be vulnerable to future warming trends and given their limited dispersal capacity, such population loss may not be offset by immigration. We also explore how next generation sequencing (NGS) is allowing unprecedented mechanistic insight into plasticity and adaptation. We conclude that in the ‘genomic era’ it may be possible to link understanding of plasticity and adaptation at the genetic level through to changes in populations providing novel insights on the redistribution of populations under future climate change. [ABSTRACT FROM AUTHOR]