Ane Timenes Laugen

• Partoft, Hanna; Bussière, Luc F; Cardinale, Massimiliano; Strand, Åsa & Laugen, Ane T (2025). Estimating a length-at-age relationship for an invasive bivalve with density-determined plastic growth. Journal of molluscan studies. ISSN 0260-1230. 91(2). doi: 10.1093/mollus/eyaf003. Full text in Research Archive Show summary

  At the base of stock assessments, used to monitor invasive aquatic species and to sustainably harvest stocks, are estimates of body growth, a key parameter regulating animal populations. However, due to lack of data, obtaining these estimates can be challenging, but analytical approaches for ‘data-poor’ situations have been developed. Currently, the Pacific oyster (Magallana gigas) is spreading in northern Europe and a need for management strategies to control the invasion is evident. Using methods developed for data-poor situations, the von Bertalanffy growth function and electronic length-frequency analysis, we analysed 17,289 length measurements of wild Pacific oysters collected between 2007 and 2018 at five sites in Sweden to estimate its growth in temperate waters. We identified two distinct growth patterns, where individuals in habitats with high bivalve density grow faster in length compared to those in less dense habitats. Additionally, we found that Pacific oyster populations in Sweden are still growing towards their asymptotic lengths and that growth is reduced but not stopped during colder months. We conclude that our analysis constitutes the basis for future stock assessment and management of the species in areas with feral populations of commercial interest.

• Rieder, Jessica; Jahnke, Marlene; André, Carl; Christiansen, Henrik; Wit, Pierre R. de & Faust, Ellika [Show all 14 contributors for this article] (2025). Seascape genomics: Assisting marine biodiversity management by combining genetic knowledge with environmental and ecological information. Marine Policy. ISSN 0308-597X. 182, p. 106867–106867. doi: 10.1016/j.marpol.2025.106867. Full text in Research Archive Show summary

  Biodiversity, including genetic diversity, is the foundation of ecosystems and supports the well-being of all organisms, including humans. Determining how the marine environment shapes genetic diversity and developing best practices to conserve it requires a multi-disciplinary approach that incorporates genomic and environmental information. Seascape genetics and genomics combine spatially resolved ecological, genomic, and environmental data, coupled with modeling to explore past, present, and future patterns of diversity and connectivity. Seascape genetics and genomics provide scientists and managers with a multi-faceted tool that can be applied across a wide range of species and incorporated into marine spatial management. Despite the proven importance of genetic diversity for species resilience, the incorporation of genetic and genomic data is grossly underrepresented in policy, decision-making, and conservation measures. Here, we aim to support the understanding and access to information on seascape genetics and genomics for conservation and environmental management practitioners. We explain how integrating environment, space, traits, and genetics or genomics can advance marine spatial management. We use two advanced case studies to outline methodology and concepts of seascape genomics and the respective policy context, although management uptake is still pending. Lastly, we review the present status of seascape genomics research and discuss challenges, strengths, and future opportunities by providing a road map. We present a successful management uptake case study that could aid the integration of seascape genomics into biodiversity management.

• Ermgassen, Philine S.E. zu; Albentosa, Marina; Bakker, Nienke; Barja, Juan L.; Blanco, Ainhoa & Bonačić, Kruno [Show all 28 contributors for this article] (2025). Identifying common factors resulting in hatchery crashes during the production of Ostrea edulis for ecological restoration in Europe. Aquatic Living Resources. ISSN 0990-7440. 38. doi: 10.1051/alr/2025016. Full text in Research Archive Show summary

  The European flat oyster, Ostrea edulis , once formed extensive reefs along European coasts. These reef ecosystems are now functionally extinct, but support for their restoration is rapidly growing. Efforts are currently limited by a bottleneck in O. edulis supply. O. edulis is a challenging species to produce in a hatchery. Currently unknown causes of high mortality and hatchery crashes must be addressed to meet the increased demand for spat from the ecological restoration sector. Here we present the results of a collaborative effort between nine European hatcheries and marine research laboratories to share recent experiences, as well as production and protocol-related data. We found that crashes were widespread and suspected to be caused by diverse culprits, including Vibrio species, predatory zooplankton, and poor water quality. A Boruta regression analysis of production data identified eleven factors including water temperature in the larval tank, broodstock origin, and number of broodstock as being potentially important in explaining crashes during the larval growth phase. Eight factors including duration of larval growth stage and larval density at transfer to the settlement tank, were identified as potentially important in explaining crashes during the settlement phase. When applied to larval mortality data of batches that did not crash, the Boruta analysis identified 13 factors, including water temperature, broodstock and larval densities and broodstock origin in determining larval mortality during the larval growth stage and two factors, number of larvae in the initial larval release and broodstock origin, during the larval settlement phase. This research highlights the value of knowledge exchange between hatchery facilities in overcoming spat production problems, identifies factors that may contribute to increased larval mortality and the risk of larval crashes, as well as the importance of developing collaborative research programmes to provide for greater commonality in data collection for future coordination and production analysis.

• Hedensjö, Alice; Strand, Åsa & Laugen, Ane T. (2025). Habitat preferences at the leading edge of a marine bioinvasion. Ecology and Evolution. 15(11). doi: 10.1002/ece3.72475. Full text in Research Archive Show summary

  To enable the early detection and eradication of invasive species, it is crucial to predict habitats with an elevated risk of invasion. Despite the fact that invaders may display initial habitat preferences and niche shifts during range expansion, studies identifying habitat associations at invasion fronts are lacking, especially those considering abundance distributions. We developed a targeted Habitat Suitability Modeling approach to predict invasion risk, focusing on the Pacific oyster ( Magallana gigas ) invasion front on the Swedish southwest coast. We show that marinas act as environmental “hotspots” for pioneering non‐native populations across broad spatial scales. The abundance observed in marinas (10.4 ind. m −2 ) was higher than that in both piers (3.3 ind. m −2 ) and natural rocky habitats (2.8 ind. m −2 ). In terms of invasion risk, marinas were predicted to promote seven times higher oyster abundance and 20 times higher oyster biomass per unit area than natural rocky habitats. While the availability of stable hard substrate influenced presence, shelter from waves influenced abundance, demonstrating the ecological distinction between species occurrence and abundance distributions with important management implications. Moreover, supporting recent genetic findings, our model reveals an unexpected low‐salinity tolerance at the invasion front, suggesting that range expansion may rather be limited by a lack of stable substrate. Our study provides novel insights into the dynamics of marine bioinvasions at leading range edges and offers a practical tool to inform early detection and proactive management of marine invasions, especially in commonly invaded anthropogenically structured habitats such as marinas.

• Greeve, Youk; Reamon, Molly C.; Bergström, Per; Strand, Åsa; Laugen, Ane T. & Lindegarth, Mats (2025). Improving Large‐Scale Population Estimates and Assessments of the Ecological Importance of Three Epifaunal Bivalve Species by Combining Distribution and Abundance Models. Ecology and Evolution. 15(12). doi: 10.1002/ece3.72586. Full text in Research Archive Show summary

  ABSTRACT Epifaunal bivalves include reef‐building organisms that provide several important ecological functions in coastal marine environments. Evaluating the distributional patterns and population sizes is key in assessing the total and relative contribution of species toward these functions and can aid in improving spatial planning and management. In this paper, the use of species distribution and abundance models as a means to improve population size estimates compared to more simplistic methods (i.e., extrapolation of mean densities) was investigated. Gradient boosting models were fitted to predict occurrences and densities of three, both native and invasive, ecologically important bivalve species (blue mussel, Mytilus edulis ; Pacific oyster, Magallana gigas ; and European oysters, Ostrea edulis ) occurring on the Swedish west coast. Bootstrapping methods were used to estimate model performance and error margins around the final predictions of total population size. Additionally, the spatial predictions were used to extract information on the key habitat types of each species. Results from the distribution models show considerable overlap in the use of shallow habitat by the native blue mussels and the invasive Pacific oyster, while the European oyster resided mostly in deeper habitats. There were, however, differences in larger geographical distribution patterns among all species. While all distribution models performed adequately (AUC ≈ 0.75–0.9 and TSS ≈ 0.45–0.65), the largest difference in estimated population size was observed when involving abundance models, reducing them by ~70% and ~50% for blue mussels and Pacific oysters respectively, while the estimate for European oysters remained similar. Importantly, estimates of total abundance when translated to biomass estimates indicated that the invasive Pacific oyster likely contributes the most to ecosystem functions associated with epibenthic bivalves in this area (~50% of total estimated dry weight biomass).

• Robert, Chloé; Monteiro, Homère J. Alves; Moan, Alan Le; Tanguy, Arnaud; Laugen, Ane Timenes & Hemmer-Hansen, Jakob [Show all 8 contributors for this article] (2025). Fine Scale Patterns of Population Structure and Connectivity in Scandinavian Flat Oysters in Scandinavia (Ostrea edulis L.). Evolutionary Applications. 18(4). doi: 10.1111/eva.70096. Full text in Research Archive Show summary

  Stocks of the European flat oyster, Ostrea edulis, have collapsed due to overfishing, habitat destruction, and pathogen outbreaks across most of their distribution range. Nonetheless, as a result of lower exploitation pressure and the absence of pathogens in the most northern part of the range, a large part of the remaining wild population can be found in relatively high densities in Scandinavia, a region in Northern Europe. However, despite recent studies focusing on flat oyster population structure along the European coast, little is known about the population structure of oysters in the Skagerrak marginal sea in Scandinavia, and how it is related to neighbouring regions. This study, therefore, aimed to investigate the population structure of flat oysters in Scandinavia, with a special emphasis on the Skagerrak. We gathered low-coverage whole-genome sequencing data from oysters in Sweden, Norway, and Denmark, the three countries that border the Skagerrak. Genetic diversity appeared to be homogeneously distributed over the sampled area in the Skagerrak, while samples collected from the east coast of Denmark and from a location with known historical farming activity on the Norwegian West Coast were genetically distinct from Skagerrak samples. A genetic barrier analysis indicated barriers to gene flow in the Baltic Sea transition zone and on the west coast of Norway. Overall, our results suggest that flat oysters from the Swedish Skagerrak coasts form a single panmictic population that is distinct from neighbouring seas, potentially allowing for regional management of stocks and restoration translocations in the area. However, the genetic composition of donor and recipient stocks should be assessed on a case-by-case basis, genetic diversity effects of hatchery practices should be monitored, and biosecurity measures need to be considered prior to any movement of stock.

• Eriksson, Pontus Felix; Kerney, Ryan; Larson-Pollock, River; Vickers, Elliana & Laugen, Ane Timenes (2025). Evidence of Holarctic distribution: common frog Rana temporaria eggs in Fennoscandia host photosymbiotic green algae (Oophila sp.). Oikos. ISSN 0030-1299. 2025(6). doi: 10.1111/oik.10752. Full text in Research Archive Show summary

  Symbiosis is a commonly occurring phenomenon, with most plants and animals being holobionts, comprising of a host and its corresponding symbionts. It is, however, less common to have a symbiont only under a specific life stage and even more so between a photosynthesizing organism and a vertebrate animal. One such relationship is found between the unicellular green algae Oophila amblystomatis and the North American yellow-spotted salamander Ambystoma maculatum, which is so far the only known endosymbiotic relationship between an alga and a vertebrate. In this study we investigate the possible occurrence of O. amblystomatis in Fennoscandian egg clutches from the genus Rana using citizen science data. We establish that egg capsules of the common frog Rana temporaria in Sweden act as a host species for two subclades of the monophyletic genus Oophila on a microgeographical scale (< 10 km) using a phylogenetic analysis. Furthermore, we investigated a possible endosymbiotic relationship between O. amblystomatis and R. temporaria embryos with f luorescence microscopy, which showed no algal invasion of frog tissue or cells in vivo. The association with a known symbiont Oophila may hold ecological importance for ontogeny, individual fitness, behavior, population dynamics and evolutionary potential of R. temporaria. However, the reciprocal benefits to both partners have not been determined for any Oophila-bearing ranid. We discuss the possible Holarctic distribution of Oophila and consider the implications of the relationship between R. temporaria and O. amblystomatis.

• Pärt, Tomas; Jeppsson, Tobias; Paquet, Matthieu; Arlt, Debora; Laugen, Ane Timenes & Low, Matthew [Show all 9 contributors for this article] (2024). Unclear relationships between mean survival rate and its environmental variance in vertebrates. Ecology and Evolution. 14(3), p. 1–7. doi: 10.1002/ece3.11104. Full text in Research Archive
• Reamon, Molly Claire; Marcussen, Johanna Bjånes; Laugen, Ane Timenes & Korslund, Lars (2024). Efficient and reliable methods for estimating the abundance of keystone coastal macrofauna over large spatial scales. Ecology and Evolution. 14(8), p. 1–15. doi: 10.1002/ece3.70088. Full text in Research Archive Show summary

  Coastal bivalves are important ecosystem engineers, and identifying critical habitats can enhance conservation outcomes for threated keystone species as well as determining hotspots for invasive species. As early action is more efficient in both conservation and mitigation of species invasions, efficient and reliable tools for mapping and monitoring species over large scales are essential. We assessed the reliability and efficiency of towed video and quadrat sampling for estimating the abundance of three keystone macrofaunal bivalve species. To assess reliability, we compared the measured density based on each of the two methods to the “true” density estimated by manually surveying an entire transect. We found that both the video and quadrat method caused underestimation of the density of bivalves, but that the amount of underestimation was comparable, and further that both methods took substantially less time than surveying an entire transect manually. The video method underestimated the abundance of Pacific oysters (Magallana gigas), European flat oysters (Ostrea edulis), and blue mussels (Mytilus spp.) by 23%, 24%, and 16%, respectively. The causes of underestimation for the two oyster species were bivalves grouped in clusters, large amounts of small individuals, and generally higher abundances. While Mytilus spp. were underestimated overall, here observer experience was important, with inexperienced observers overestimating and experienced observers underestimating. Our study found both methods to be reliable and efficient for estimating the abundance of three keystone macrofaunal species, suggesting their potential applicability to other sessile or slow-moving species. We propose that these methods, due to their efficiency, can advance scientific knowledge and enhance conservation outcomes by establishing population baselines, assessing trends over time, and identifying and protecting critical habitats.

• Ermgassen, Philine S. E. zu; McCormick, Hannah; Debney, Alison; Fariñas-Franco, José M.; Gamble, Celine & Gillies, Chris [Show all 13 contributors for this article] (2024). European Native Oyster Reef Ecosystems Are Universally Collapsed. Conservation Letters. doi: 10.1111/conl.13068. Full text in Research Archive
• Meriggi, Carlotta Matilde Mariafrancesc; Johnson, Richard K.; Laugen, Ane Timenes & Drakare, Stina (2024). Effects of temperature and N:P ratio on the invasion success of the cyanobacterium Raphidiopsis raciborskii. Aquatic Invasions. ISSN 1798-6540. 19(3), p. 275–286. doi: 10.3391/ai.2024.19.3.134464. Full text in Research Archive Show summary

  The tropical invasive freshwater cyanobacterium Raphidiopsis raciborskii, first recorded in Central Europe about two decades ago, is now a relatively widespread species, expanding its geographic range. Currently, however, there are no records of this species in Sweden. As a bloom-forming and toxin-producing species, future population growths of R. raciborskii could negatively affect local biodiversity and ecosystem services. Hence, there is an urgent need to understand the factors controlling its capability of establishment in Northern European lakes. We performed a laboratory experiment to study the competitive success of R. raciborskii when interacting with other phytoplankton from major taxonomic groups typically found in Scandinavian lakes (diatoms, green algae, and cyanobacteria). The experimental settings included three temperature conditions (17; 22; 26 °C) and three different nutrient conditions (N:P ratios 8:1; 16:1; 32:1). The experiment was performed in a semi-continuous culture setup to test the invasion success of R. raciborskii. Raphidiopsis raciborskii did not become the dominant species in any of the tested conditions; however, it was able to grow and maintain its biomass in all treatments, also in relatively low temperature (17 °C). Temperature played an important role in the phytoplankton community composition, especially for the cyanobacterial group. Raphidiopsis raciborskii was more successful than Planktothrix agardhii, but less dominant than Microcystis aeruginosa. Temperature is thus important in determining the potential survival and settlement of the invasive R. raciborskii in lakes.

• Gustafsson, Malin; Strand, Åsa; Laugen, Ane Timenes; Albretsen, Jon; André, Carl & Broström, Göran [Show all 13 contributors for this article] (2024). Unlocking the secret life of blue mussels: Exploring connectivity in the Skagerrak through biophysical modeling and population genomics. Evolutionary Applications. 17(5), p. 1–18. doi: 10.1111/eva.13704. Full text in Research Archive Show summary

  Knowledge of functional dispersal barriers in the marine environment can be used to inform a wide variety of management actions, such as marine spatial planning, restoration efforts, fisheries regulations, and invasive species management. Locations and causes of dispersal barriers can be studied through various methods, including movement tracking, biophysical modeling, demographic models, and genetics. Combining methods illustrating potential dispersal, such as biophysical modeling, with realized dispersal through, e.g., genetic connectivity estimates, provides particularly useful information for teasing apart potential causes of observed barriers. In this study, we focus on blue mussels (Mytilus edulis) in the Skagerrak—a marginal sea connected to the North Sea in Northern Europe—and combine biophysical models of larval dispersal with genomic data to infer locations and causes of dispersal barriers in the area. Results from both methods agree; patterns of ocean currents are a major structuring factor in the area. We find a complex pattern of source-sink dynamics with several dispersal barriers and show that some areas can be isolated despite an overall high dispersal capability. Finally, we translate our finding into management advice that can be used to sustainably manage this ecologically and economically important species in the future.

• Vences, Miguel; Sachs, Maria; Irisarri, Iker; Bartels, Fabian; Eriksson, Pontus Felix & Künzel, Sven [Show all 12 contributors for this article] (2024). Phylotranscriptomic relationships of the Oophila clade of green algae associated to amphibian egg masses. Molecular Phylogenetics and Evolution. ISSN 1055-7903. 200. doi: 10.1016/j.ympev.2024.108165. Full text in Research Archive
• Monteiro, Homère J. Alves; Bekkevold, Dorte; Pacheco, George Antunes; Mortensen, Stein; Lou, Runyang Nicolas & Therkildsen, Nina O. [Show all 15 contributors for this article] (2024). Genome-Wide Population Structure in a Marine Keystone Species, the European Flat Oyster (Ostrea edulis). Molecular Ecology. ISSN 0962-1083. doi: 10.1111/mec.17573. Full text in Research Archive Show summary

  Ostrea edulis, the European flat oyster, was once a widespread economically and ecologically important marine species, but has suffered dramatic declines over the past two centuries. Consequently, there has been a surge in European restoration efforts, many of which focus on restocking as a conservation measure. In this study, we used whole-genome sequencing (WGS) data to investigate the population structure, demographic history, and patterns of local adaptation of O. edulis across its natural distribution with increased sampling densities at Scandinavian localities. Results revealed seven distinct genetic clusters, including previously undescribed complex population structure in Norway, and evidence for introgression between genetic clusters in Scandinavia. We detected large structural variants (SVs) on three pseudo-chromosomes. These megabase long regions were characterised by strong linkage disequilibrium and clear geographical differentiation, suggestive of chromosomal inversions potentially associated with local adaptation. The results indicated that genomic traces of past translocations of non-native O. edulis were still present in some individuals, but overall, we found limited evidence of major impacts of translocations on the scale of contemporary population structure. Our findings highlight the importance of considering population structure and signatures of selection in the design of effective conservation strategies to preserve and restore wild native European flat oyster populations, and we provide direct knowledge safeguarding sustainable mitigation actions in this important species.

• Solbreck, Christer; Cassel‐Lundhagen, Anna; Laugen, Ane T. & Kaňuch, Peter (2023). Post‐glacial colonization of the Fennoscandian coast by a plant parasitic insect with an unusual life history. Ecology and Evolution. 13(4). doi: 10.1002/ece3.9996. Full text in Research Archive Show summary

  Abstract Species that exhibit very peculiar ecological traits combined with limited dispersal ability pose a challenge to our understanding of ecological and evolutionary mechanisms. This is especially true when they have managed to spread over long distances, overcome physical barriers, and colonize large areas. Climate and landscape changes, trophic web relations, as well as life history all interact to shape migration routes and present‐day species distributions and their population genetic structures. Here we analyzed the post‐glacial colonization of northern Europe by the gall midge Contarinia vincetoxici , which is a monophagous parasite on the perennial herb White swallowwort ( Vincetoxicum hirundinaria ). This insect not only has a narrow feeding niche but also limited dispersal ability and an exceptionally long dormancy. Gall midge larvae ( n  = 329) were collected from 16 sites along its distribution range in Denmark, Sweden, and Finland. Using microsatellite loci and knowledge of the species and the regions' history, we investigated the role of landscape change, host plant distribution, insect population dynamics, and life history in shaping the population genetic structure of the insect. We devoted particular interest to the role of the insect's presumed poor dispersal capacity in combination with its exceptionally extended diapause. We found significant levels of local inbreeding (95% highest posterior density interval = 0.42–0.47), low‐level within‐population heterozygosity (mean H E  = 0.45, range 0.20–0.61) with private alleles in all populations except two. We also found significant ( p  < .001) regional isolation‐by‐distance patterns, suggesting regularly recurring mainly short‐distance dispersal. According to approximate Bayesian computations, C. vincetoxici appears to have colonized the study area via wind‐aided flights from remote areas approximately 4600–700 years before present when the land has gradually risen above the sea level. Extremely long dormancy periods have allowed the species to “disperse in time”, thereby aiding population persistence despite generally low census population sizes.

• Ermgassen, Philine S.E. Zu; Albentosa, Marina; Bakker, Nienke; Blanco, Ainhoa; Bonačić, Kruno & Carboni, Stefano [Show all 26 contributors for this article] (2023). Ten priority questions for increasing the consistency and success in hatchery production of the European flat oyster for habitat restoration. Aquatic Living Resources. ISSN 0990-7440. 36. doi: 10.1051/alr/2023025. Full text in Research Archive Show summary

  The European flat oyster, Ostrea edulis, once formed extensive reef habitats throughout European seas and estuaries. These reefs are now largely functionally extinct, yet interest and support for their restoration is rapidly growing. A major bottleneck to scaling up oyster reef restoration is the lack of available oysters to supply the growing demand. This study aimed to identify the ten questions which, if answered, would increase the consistency and success in hatchery production of O. edulis for habitat restoration. Candidate questions were submitted by representatives from twelve commercial and research hatcheries across Europe. The list of 98 candidate questions were collaboratively discussed by experts from nine research hatcheries across eight countries in Europe, to identify the top ten questions via an iterative and open process. Questions were grouped into the following themes: conditioning and feeding, larval rearing, disease and water quality, hatchery protocol, genetics, and hatchery management. There were several overarching topics spanning these themes, including diet optimisation, maximising the effective population size, and developing the technical skillbase in order to increase hatchery production to meet the projected increase in demand for oyster seed for habitat restoration efforts. We anticipate this list will provide a starting point for collaborative research efforts across Europe, as well as assisting policy makers and funders in identifying key knowledge gaps.

• Meriggi, Carlotta; Mershad, Maliheh; Johnson, Richard K.; Laugen, Ane Timenes & Drakare, Stina (2023). Challenges in supplying empirical proof for predictions derived from Species Distribution Models (SDMs): the case of an invasive cyanobacterium. ISME Communications. 3. doi: 10.1038/s43705-023-00264-2. Full text in Research Archive Show summary

  Species distribution models (SDMs) calibrated with bioclimatic variables revealed a high probability for range expansion of the invasive toxin producing cyanobacterium, Raphidiopsis raciborskii to Sweden, where no reports of its presence have hitherto been recorded. While predictions focused on the importance of climate variables for possible invasion, other barriers to dispersal and successful colonization need to be overcome by the species for successful invasion. In this study, we combine field-based surveys of R. raciborskii (microscopy and molecular analysis using species-specific primers) of 11 Swedish lakes and in-silico screening of environmental DNA using 153 metagenomic datasets from lakes across Europe to validate the SDMs prediction. Field-based studies in lakes with high/low predicted probability of occurrence did not detect the presence of R. raciborskii, and in-silico screening only detected hints of its presence in 5 metagenomes from lakes with probability ranging from 0.059 to 0.825. The inconsistencies between SDMs results and both field-based/in-silico monitoring could be due to either sensitivity of monitoring approaches in detecting early invasions or uncertainties in SDMs that focused solely on climate drivers. However, results highlight the necessity of proactive monitoring with high temporal and spatial frequency.

• Solbreck, Christer; Cassel-Lundhagen, Anna; Laugen, Ane Timenes & Kaňuch, Peter (2023). Post-glacial colonization of the Fennoscandian coast by a plant parasitic insect with an unusual life history. Ecology and Evolution. 13(4). doi: 10.1002/ece3.9996. Full text in Research Archive Show summary

  Species that exhibit very peculiar ecological traits combined with limited dispersal ability pose a challenge to our understanding of ecological and evolutionary mechanisms. This is especially true when they have managed to spread over long distances, overcome physical barriers, and colonize large areas. Climate and landscape changes, trophic web relations, as well as life history all interact to shape migration routes and present-day species distributions and their population genetic structures. Here we analyzed the post-glacial colonization of northern Europe by the gall midge Contarinia vincetoxici, which is a monophagous parasite on the perennial herb White swallowwort (Vincetoxicum hirundinaria). This insect not only has a narrow feeding niche but also limited dispersal ability and an exceptionally long dormancy. Gall midge larvae (n = 329) were collected from 16 sites along its distribution range in Denmark, Sweden, and Finland. Using microsatellite loci and knowledge of the species and the regions' history, we investigated the role of landscape change, host plant distribution, insect population dynamics, and life history in shaping the population genetic structure of the insect. We devoted particular interest to the role of the insect's presumed poor dispersal capacity in combination with its exceptionally extended diapause. We found significant levels of local inbreeding (95% highest posterior density interval = 0.42–0.47), low-level within-population heterozygosity (mean HE = 0.45, range 0.20–0.61) with private alleles in all populations except two. We also found significant (p < .001) regional isolation-by-distance patterns, suggesting regularly recurring mainly short-distance dispersal. According to approximate Bayesian computations, C. vincetoxici appears to have colonized the study area via wind-aided flights from remote areas approximately 4600–700 years before present when the land has gradually risen above the sea level. Extremely long dormancy periods have allowed the species to “disperse in time”, thereby aiding population persistence despite generally low census population sizes.

• Meriggi, Carlotta; Drakare, Stina; Lacambra, Ester Polaina; Johnson, Richard K. & Laugen, Ane T (2022). Species distribution models as a tool for early detection of the invasive Raphidiopsis raciborskii in European lakes. Harmful Algae. ISSN 1568-9883. 113. doi: 10.1016/j.hal.2022.102202. Full text in Research Archive Show summary

  In freshwater habitats, invasive species and the increase of cyanobacterial blooms have been identified as a major cause of biodiversity loss. The invasive cyanobacteria Raphidiopsis raciborskii a toxin-producing and bloom-forming species affecting local biodiversity and ecosystem services is currently expanding its range across Europe. We used species distribution models (SDMs) and regional bioclimatic environmental variables, such as temperature and precipitation, to identify suitable areas for the colonization and survival of R. raciborskii, with special focus on the geographic extent of potential habitats in Northern Europe. SDMs predictions uncovered areas of high occurrence probability of R. raciborskii in locations where it has not been recorded yet, e.g. some areas in Central and Northern Europe. In the southeastern part of Sweden, areas of suitable climate for R. raciborskii corresponded with lakes of high concentrations of total phosphorus, increasing the risk of the species to thrive. To our knowledge, this is the first attempt to predict areas at high risk of R. raciborskii colonization in Europe. The results from this study suggest several areas across Europe that would need monitoring programs to determine if the species is present or not, to be able to prevent its potential colonization and population growth. Regarding an undesirable microorganism like R. raciborskii, authorities may need to start information campaigns to avoid or minimize the spread.

• Laugen, Ane T; Hosken, David J.; Reinhold, Klaus; Schwarzenbach, Gioia A.; Hoeck, Paquita E. A. & Bussière, Luc F. [Show all 8 contributors for this article] (2022). Sperm competition in yellow dung flies: No consistent effect of sperm size. Journal of Evolutionary Biology. ISSN 1010-061X. 35(10), p. 1309–1318. doi: 10.1111/jeb.14073. Full text in Research Archive Show summary

  The male competition for fertilization that results from female multiple mating promotes the evolution of increased sperm numbers and can impact sperm morphology, with theory predicting that longer sperm can at times be advantageous during sperm competition. If so, males with longer sperm should sire more offspring than competitors with shorter sperm. Few studies have directly tested this prediction, and findings are inconsistent. Here we assessed whether longer sperm provide a competitive advantage in the yellow dung fly (Scathophaga stercoraria; Diptera: Scathophagidae). Initially, we let brothers with different temperature-mediated mean sperm lengths compete – thus minimizing confounding effects of genetic background – and found no clear advantage of longer sperm. We then used flies from lines subjected to bidirectional selection on phenoloxidase activity that had shown correlated evolutionary responses in sperm and female spermathecal duct lengths. This experiment also yielded no main effect of sperm size on siring success. Instead, there was a trend for a shorter-sperm advantage, but only when competing in females with longer spermathecal ducts. Our data corroborated many previously reported findings (last-male precedence, effects of copula duration and body size), suggesting our failure to find sperm size effects is not inherently due to our experimental protocols. We conclude that longer sperm are not competitively superior in yellow dung flies under most circumstances, and that, consistent with previous work, in this species competitive fertilization success is primarily determined by the relative numbers of sperm competing.

• Kaňuch, Peter; Kiehl, Berrit; Cassel-Lundhagen, Anna; Laugen, Ane T.; Low, Matthew & Berggren, Åsa (2020). Gene flow relates to evolutionary divergence among populations at the range margin. PeerJ. 8, p. 10036–10036. doi: 10.7717/peerj.10036. Full text in Research Archive Show summary

  Background Morphological differentiation between populations resulting from local adaptations to environmental conditions is likely to be more pronounced in populations with increasing genetic isolation. In a previous study a positive clinal variation in body size was observed in isolated Roesel’s bush-cricket, Metrioptera roeselii , populations, but were absent from populations within a continuous distribution at the same latitudinal range. This observational study inferred that there was a phenotypic effect of gene flow on climate-induced selection in this species. Methods To disentangle genetic versus environmental drivers of population differences in morphology, we measured the size of four different body traits in wild-caught individuals from the two most distinct latitudinally-matched pairs of populations occurring at about 60°N latitude in northern Europe, characterised by either restricted or continuous gene flow, and corresponding individuals raised under laboratory conditions. Results Individuals that originated from the genetically isolated populations were always bigger (femur, pronotum and genital appendages) when compared to individuals from latitudinally-matched areas characterised by continuous gene flow between populations. The magnitude of this effect was similar for wild-caught and laboratory-reared individuals. We found that previously observed size cline variation in both male and female crickets was likely to be the result of local genetic adaptation rather than phenotypic plasticity. Conclusions This strongly suggests that restricted gene flow is of major importance for frequencies of alleles that participate in climate-induced selection acting to favour larger phenotypes in isolated populations towards colder latitudes.

• Ermgassen, Philine S. E. zu; Bonačić, Kruno; Boudry, Pierre; Bromley, Cass A.; Cameron, Tom C. & Colsoul, Bérenger [Show all 22 contributors for this article] (2020). Forty questions of importance to the policy and practice of native oyster reef restoration in Europe. Aquatic conservation. ISSN 1052-7613. 30(11), p. 2049–2049. doi: 10.1002/aqc.3462. Full text in Research Archive Show summary

  Abstract Oyster reefs are among the most threatened marine habitats globally. In Europe, oyster reefs have been extirpated from most locations within their historical range. Active restoration of the native oyster ( Ostrea edulis ) in Europe has grown substantially in recent years. In sharing experiences between oyster restoration projects in Europe at the Native Oyster Restoration Alliance conference, NORA2, in Edinburgh in May 2019, it became apparent that a number of similar barriers are experienced. This study identified the top 40 questions, which, if answered, would have the greatest influence on the policy and practice of oyster restoration in Europe. Initially 71 people were consulted across 28 institutions and 11 European countries to generate 194 questions. An established process of one round of pre‐workshop voting followed by a one‐day online workshop and two post‐workshop rounds of voting resulted in the final 40 questions. Questions were broadly grouped into the following 10 themes: baselines, site selection, restoration methods, quantifying benefits, disease management, biosecurity, genetic diversity and population differentiation, policy and management, novel technologies, and current and future threats. We anticipate that this list will provide a starting point for developing collaborative projects across the NORA network, as well as assisting policy makers and funders with identifying key areas that need to be addressed in order to overcome existing barriers to scaling up oyster restoration in Europe.

• Josefsson, Jonas; Hiron, Matthew; Arlt, Debora; Auffret, Alistair G.; Berg, Åke & Chevalier, Mathieu [Show all 19 contributors for this article] (2020). Improving scientific rigour in conservation evaluations and a plea deal for transparency on potential biases. Conservation Letters. 13(5). doi: 10.1111/conl.12726. Full text in Research Archive Show summary

  Abstract The delivery of rigorous and unbiased evidence on the effects of interventions lay at the heart of the scientific method. Here we examine scientific papers evaluating agri‐environment schemes, the principal instrument to mitigate farmland biodiversity declines worldwide. Despite previous warnings about rudimentary study designs in this field, we found that the majority of studies published between 2008 and 2017 still lack robust study designs to strictly evaluate intervention effects. Potential sources of bias that arise from the correlative nature are rarely mentioned, and results are still promoted by using a causal language. This lack of robust study designs likely results from poor integration of research and policy, while the erroneous use of causal language and an unwillingness to discuss bias may stem from publication pressures. We conclude that scientific reporting and discussion of study limitations in intervention research must improve and propose some practices toward this goal.

• Kaňuch, Peter; Berrit, Kiehl; Cassel-Lundhagen, Anna; Laugen, Ane T; Low, Matthew & Berggren, Åsa (2020). Gene flow relates to evolutionary divergence among populations at the range margin. PeerJ. 8(3). doi: 10.7717/peerj.10036. Full text in Research Archive
• Ermgassen, Philine zu; Bonačić, Kruno; Boudry, Pierre; Bromley, Cass A.; Cameron, Tom C. & Colsoul, Bérenger [Show all 22 contributors for this article] (2020). Forty questions of importance to the policy and practice of native oyster reef restoration in Europe. Aquatic conservation. ISSN 1052-7613. 30, p. 2038–2049. doi: 10.1002/aqc.3462. Full text in Research Archive
• Josefsson, Jonas; Hiron, Matthew; Arlt, Debora; Auffret, Alistair G.; Berg, Åke & Chevalier, Mathieu [Show all 19 contributors for this article] (2020). Improving scientific rigour in conservation evaluations and a plea deal for transparency on potential biases. Conservation Letters. 13(5). doi: 10.1111/conl.12726. Full text in Research Archive
• Faust, Ellika; Andre, Carl; Meurling, Sara; Kochmann, Judith; Christiansen, Henrik & Fast-Jensen, Lasse [Show all 9 contributors for this article] (2017). Origin and route of establishment of the invasive Pacific oyster (Crassostrea gigas) in Scandinavia. Marine Ecology Progress Series. ISSN 0171-8630. 575, p. 95–105. doi: 10.3354/meps12219. Full text in Research Archive
• Forsgren, Eva; Locke, Barbara; Semberg, Emilia; Laugen, Ane Timenes & Miranda, Joachim R De (2017). Sample preservation, transport and processing strategies for honeybee RNA extraction: Influence on RNA yield, quality, target quantification and data normalization. Journal of Virological Methods. ISSN 0166-0934. 246, p. 81–89. doi: 10.1016/j.jviromet.2017.04.010. Full text in Research Archive
• Engström-Öst, Jonna; Rasic, Ivana Savatijevic; Brutemark, Andreas; Rancken, Romi; Simić, Gordana Subakov & Laugen, Ane Timenes (2015). Can <i>Cylindrospermopsis raciborskii</i> invade the Baltic Sea? Environmental Reviews. ISSN 1181-8700. 23(2), p. 169–169. doi: 10.1139/er-2014-0062. Full text in Research Archive Show summary

  Management actions against invasive species are usually most efficient during early stages of invasion. Monitoring for early detection is therefore part of many management plans. However, if monitoring efforts do not match suitable habitat areas, detecting the initial stages of an invasion may fail. We highlight this mismatch by assessing which areas have suitable habitats for an invasion of the cyanobacterium Cylindrospermopsis raciborskii in the Baltic Sea, and compare these with the areas that are currently monitored for algal blooms. Establishment of this potential toxin-producer in the Baltic Sea could have serious socio-economic consequences for tourism and recreation, as well as fisheries and aquaculture in the coastal regions. We estimate the coastal areas of the eastern Gulf of Finland as the most suitable area for establishment because of low salinity and high summer seawater surface temperatures. The species is not yet reported in the Baltic Sea, but in the suitable-habitat areas indicated by our assessment, very little monitoring is currently being done. We suggest several lines of research and monitoring to increase the probability of early detection and better predictions for the future distribution of the species.

• Öberg, Meit; Arlt, Debora; Pärt, Tomas; Laugen, Ane T; Eggers, Sönke & Low, Matthew (2015). Rainfall during parental care reduce both reproductive and survival components of fitness in a passerine bird. Ecology and Evolution. 5, p. 345–356. doi: 10.1002/ece3.1345. Full text in Research Archive
• Engström-Ost, Jonna; Rasic, Ivana Savatijevic; Brutemark, Andreas; Rancken, Romi; Simić, Gordana Subakov & Laugen, Ane T (2015). Can Cylindrospermopsis raciborskii invade the Baltic Sea? Environmental Reviews. ISSN 1181-8700. 23, p. 161–169. doi: 10.1139/er-2014-0062. Full text in Research Archive
• Öberg, Meit; Arlt, Debora; Pärt, Tomas; Laugen, Ane Timenes; Eggers, Sönke & Low, Matthew (2014). Rainfall during parental care reduces reproductive and survival components of fitness in a passerine bird. Ecology and Evolution. 5(2), p. 356–356. doi: 10.1002/ece3.1345. Full text in Research Archive Show summary

  Abstract Adverse weather conditions during parental care may have direct consequences for offspring production, but longer‐term effects on juvenile and parental survival are less well known. We used long‐term data on reproductive output, recruitment, and parental survival in northern wheatears ( Oenanthe oenanthe ) to investigate the effects of rainfall during parental care on fledging success, recruitment success (juvenile survival), and parental survival, and how these effects related to nestling age, breeding time, habitat quality, and parental nest visitation rates. While accounting for effects of temperature, fledging success was negatively related to rainfall (days > 10 mm) in the second half of the nestling period, with the magnitude of this effect being greater for breeding attempts early in the season. Recruitment success was, however, more sensitive to the number of rain days in the first half of the nestling period. Rainfall effects on parental survival differed between the sexes; males were more sensitive to rain during the nestling period than females. We demonstrate a probable mechanism driving the rainfall effects on reproductive output: Parental nest visitation rates decline with increasing amounts of daily rainfall, with this effect becoming stronger after consecutive rain days. Our study shows that rain during the nestling stage not only relates to fledging success but also has longer‐term effects on recruitment and subsequent parental survival. Thus, if we want to understand or predict population responses to future climate change, we need to consider the potential impacts of changing rainfall patterns in addition to temperature, and how these will affect target species' vital rates.

• Forsgren, Eva & Laugen, Ane Timenes (2014). Prognostic value of using bee and hive debris samples for the detection of American foulbrood disease in honey bee colonies. Apidologie. ISSN 0044-8435. 45(1), p. 20–20. doi: 10.1007/s13592-013-0225-6. Full text in Research Archive Show summary

  The objective of this study was to compare how well the detection of Paenibacillus larvae in samples of live bees or in accumulated winter debris collected from the bottom of beehives relates to symptoms of American foulbrood in honey bee colonies. Fifty-eight colonies in one commercial beekeeping operation were inspected for disease symptoms and assayed for P . larvae using culture-based techniques and PCR. The results show that culture-based techniques are more accurate than recently published PCR methods for detecting the bacterium in clinically diseased colonies, and that the prognostic value of bacterial colony counts from bee samples is superior to colony counts from debris. However, if the objective is to monitor the prevalence of the bacterium irrespective of disease symptoms, the preferable method is PCR analysis of accumulated winter hive debris.

• Laugen, Ane Timenes; Engelhard, Georg H.; Whitlock, Rebecca; Arlinghaus, Robert; Dankel, Dorothy & Dunlop, Erin [Show all 24 contributors for this article] (2014). Evolutionary impact assessment: accounting for evolutionary consequences of fishing in an ecosystem approach to fisheries management. Fish and Fisheries. ISSN 1467-2960. 15(1), p. 65–96. doi: 10.1111/faf.12007. Full text in Research Archive
• Heino, Mikko Petteri; Baulier, Loic; Boukal, David; Ernande, Bruno; Johnston, Fiona & Mollet, Fabian [Show all 24 contributors for this article] (2013). Can fisheries-induced evolution shift reference points for fisheries management? ICES Journal of Marine Science. ISSN 1054-3139. 70(4), p. 707–721. doi: 10.1093/icesjms/fst077. Full text in Research Archive
• Terenius, Olle; Lindh, Jenny M.; Eriksson-Gonzales, Karolina; Bussière, Luc; Laugen, Ane Timenes & Bergquist, Helen [Show all 8 contributors for this article] (2012). Midgut bacterial dynamics in Aedes aegypti. FEMS Microbiology Ecology. ISSN 0168-6496. 80(3), p. 565–565. doi: 10.1111/j.1574-6941.2012.01317.x. Full text in Research Archive Show summary

  In vector mosquitoes, the presence of midgut bacteria may affect the ability to transmit pathogens. We have used a laboratory colony of Aedes aegypti as a model for bacterial interspecies competition and show that after a blood meal, the number of species (culturable on Luria–Bertani agar) that coexist in the midgut is low and that about 40% of the females do not harbor any cultivable bacteria. We isolated species belonging to the genera Bacillus, Elizabethkingia, Enterococcus, Klebsiella, Pantoea, Serratia, and Sphingomonas, and we also deter- mined their growth rates, antibiotic resistance, and ex vivo inhibition of each other. To investigate the possible existence of coadaptation between midgut bacteria and their host, we fed Ae. aegypti cohorts with gut bacteria from human, a frog, and two mosquito species and followed the bacterial population growth over time. The dynamics of the different species suggests coadaptation between host and bacteria, and interestingly, we found that Pantoea stewartii isolated from Ae. aegypti survive better in Ae. aegypti as compared to P. ste- wartii isolated from the malaria mosquito Anopheles gambiae.

• ALHO, J. S.; HERCZEG, G.; Laugen, Ane Timenes; RÄSÄNEN, K.; LAURILA, A. & Merilä, Juha (2010). Allen’s rule revisited: quantitative genetics of extremity length in the common frog along a latitudinal gradient. Journal of Evolutionary Biology. ISSN 1010-061X. 24(1), p. 70–70. doi: 10.1111/j.1420-9101.2010.02141.x. Full text in Research Archive Show summary

  Ecogeographical rules linking climate to morphology have gained renewed interest because of climate change. Yet few studies have evaluated to what extent geographical trends ascribed to these rules have a genetic, rather than environmentally determined, basis. This applies especially to Allen’s rule, which states that the relative extremity length decreases with increasing latitude. We studied leg length in the common frog (Rana temporaria) along a 1500 km latitudinal gradient utilizing wild and common garden data. In the wild, the body size–corrected femur and tibia lengths did not conform to Allen’s rule but peaked at mid-latitudes. However, the ratio of femur to tibia length increased in the north, and the common garden data revealed a genetic cline consistent with Allen’s rule in some trait and treatment combinations. While selection may have shortened the leg length in the north, the genetic trend seems to be partially masked by environmental effects.

• Kuparinen, Anne; Laugen, Ane Timenes; Laurila, Anssi & Merilä, Juha (2010). Developmental threshold model challenged by temperature. Evolutionary Ecology Research. ISSN 1522-0613. 12, p. 821–829. Full text in Research Archive Show summary

  Question: Does the L-shape of the reaction norm for age and size at ontogenetic transitions arise irrespective of temperature? The developmental threshold model suggests that this shape arises due to a threshold in body size to undertake the transition. Data studied: Ages and sizes at metamorphosis measured in a common garden experiment in Rana temporaria originating from six populations along a latitudinal gradient. Individuals were exposed to three temperature treatments and two levels of food. Search method: Population-specific age and size at metamorphosis were plotted against each other, and the shape of the reaction norm across populations was further illustrated by an exponential decay function. The observed patterns were further explored via linear mixed-effect models. Conclusion: The L-shape of the reaction norm depends on temperature, suggesting that at low temperature a developmental threshold in age rather than in size regulates the process of metamorphosis.

• Laurila, Anssi; Lindgren, Beatrice & Laugen, Ane Timenes (2008). ANTIPREDATOR DEFENSES ALONG A LATITUDINAL GRADIENT IN <i>RANA TEMPORARIA</i>. Ecology. ISSN 0012-9658. 89(5), p. 1413–1413. doi: 10.1890/07-1521.1. Full text in Research Archive Show summary

  Antipredator defenses are expected to decrease toward higher latitudes because predation rates are predicted to decrease with latitude. However, latitudinal variation in predator avoidance and defense mechanisms has seldom been studied. We studied tadpole antipredator defenses in seven Rana temporaria populations collected along a 1500‐km latitudinal gradient across Sweden, along which previous studies have found increasing tadpole growth and development rates. In a laboratory common garden experiment, we measured behavioral and morphological defenses by raising tadpoles in the presence and absence of a predator ( Aeshna dragonfly larva) in two temperature treatments. We also estimated tadpole survival in the presence of free‐ranging predators and compared predator densities between R. temporaria breeding ponds situated at low and high latitudes. Activity and foraging were generally positively correlated with latitude in the common garden experiment. While all populations responded to predator presence by decreasing activity and foraging, high‐latitude populations maintained higher activity levels in the presence of the predator. All populations exhibited defensive morphology in body and tail shape. However, whereas tail depth tended to increase with latitude in the presence of predator, it did not change with latitude in the absence of the predator. Predator presence generally increased larval period and decreased growth rate. In the southern populations, predator presence tended to have a negative effect on metamorphic size, whereas in the northern populations predators had little or a positive effect on size. Latitude of origin had a strong effect on survival in the presence of a free‐ranging predator, with high‐latitude tadpoles experiencing higher mortality than those from the low latitudes. In the wild, predator densities were significantly lower in high‐latitude than in mid‐latitude breeding ponds. Although the higher activity level in the northern populations seems to confer a significant survival disadvantage under predation risk, it is probably needed to maintain the high growth and development rates. However, the occurrence of R. temporaria at high latitudes may be facilitated by the lower predator densities in the north.

• Laugen, Ane Timenes; KRUUK, LOESKE E. B.; LAURILA, ANSSI; RÄSÄNEN, KATJA; STONE, JONATHAN & Merilä, Juha (2005). Quantitative genetics of larval life-history traits in <i>Rana temporaria</i> in different environmental conditions. Genetics Research. ISSN 0016-6723. 86(3), p. 170–170. doi: 10.1017/s0016672305007810. Full text in Research Archive Show summary

  The degree to which genetic variation in a given trait varies among different populations of the same species and across different environments has seldom been quantified in wild vertebrate species. We investigated the expression of genetic variability and maternal effects in three larval life-history traits of the amphibian Rana temporaria . In a factorial laboratory experiment, five widely separated populations (max. 1600 km) were subjected to two different environmental treatments. Animal model analyses revealed that all traits were heritable ( h 2 ≈0·20) in all populations and under most treatment combinations. Although the cross-food treatment genetic correlations were close to unity, heritabilities under a restricted food regime tended to be lower than those under an ad libitum food regime. Likewise, maternal effects ( m 2 ≈0·05) were detected in most traits, and they tended to be most pronounced under restricted food conditions. We detected several cross-temperature genetic and maternal effects correlations that were lower than unity, suggesting that genotype–environment interactions and maternal effect–environment interactions are a significant source of phenotypic variation. The results reinforce the perspective that although the expression of genetic and maternal effects may be relatively homogeneous across different populations of the same species, local variation in environmental conditions can lead to significant variation in phenotypic expression of quantitative traits through genotype–environment and maternal effect–environment interactions.

• Laugen, Ane Timenes; Laurila, Anssi; Jönsson, K. Ingemar; Söderman, Fredrik & Merilä, Juha (2005). Do common frogs (Rana temporaria) follow Bergmann’s rule? Evolutionary Ecology Research. ISSN 1522-0613. 7, p. 717–731. doi: https:/portal.research.lu.se/en/publications/do-common-frogs-rana-temporaria-follow-bergmanns-rule/. Full text in Research Archive Show summary

  Questions: Does intraspecific extension of Bergmanns rule – larger size within a species in cooler areas – hold true for ectotherms in general, and for the common frog (Rana temporaria) in particular? What is the relative importance of genetic and environmental factors (i.e. direct environmental induction) in determining latitudinal patterns of body size variation in common frogs? Methods: We tested for a positive association between mean body size and latitude in common frogs (Rana temporaria) across a 1600 km long latitudinal gradient in Scandinavia both for wild-collected adults and laboratory-reared metamorphs. Results: In adults, the mean body size increased from south to mid-latitudes, and declined thereafter. This occurred despite the fact that the mean age of adult frogs increased with increasing latitude, and age and body size were positively correlated. The latitudinal pattern of body size variation in metamorphs reared in a common garden experiment was similar to that observed among wild-caught adults. Conclusions: The results suggest that the concave pattern of body size variation across the latitudinal cline may be at least partly genetically determined, and that although there is considerable geographic variation in mean body size of R. temporaria, this variation does not conform with Bergmann’s rule.

• Merilä, Juha; Laurila, Anssi; Laugen, Ane Timenes & Räsänen, Katja (2004). Heads or tails? Variation in tadpole body proportions in response to temperature and food stress. Evolutionary Ecology Research. ISSN 1522-0613. 6, p. 727–738. Full text in Research Archive Show summary

  Given sufficient time and genetic variation, populations of ectothermic animals living in different thermal environments are expected to diverge in their thermal optima for growth. Several recent studies have used common frog (Rana temporaria) tadpoles as models to study animal adaptation to geographic variation in ambient temperatures, but little attention has been paid to how the growth of different body parts responds to variation in temperature. We examined the variation in early growth in body, tail and relative tail length of common frog tadpoles in a common garden experiment that subjected individuals from six populations situated along a 1600-km latitudinal gradient to different temperature and food treatments. We found a high degree of latitudinally unordered inter-populational differentiation in relative tail length, and that increasing levels of environmental stress (low temperature and restricted food) lead to increased mean relative tail length. This occurred mainly because of changes in body growth, not because of changes in tail growth per se. This suggests that growth of the tail itself is less sensitive to environmental stress than body growth, but at the same time the relative length of tail can be a good indicator of growth conditions experienced by individuals. In general, the results do not support the earlier proposition that common frog tadpoles in the south have relatively longer tails due to increased risk of predation, but indirect evidence was found to support the contention that the populations along the latitudinal gradient have different thermal optima for growth as indicated by latitudinally ordered differences in how relative tail length changed in response to temperature treatments.

• Pålsson, Katinka; Jaenson, Thomas G. T.; Dias, Francisco; Laugen, Ane Timenes & Björkman, Anders (2004). Endophilic<i>Anopheles</i>Mosquitoes in Guinea Bissau, West Africa, in Relation to Human Housing Conditions. Journal of medical entomology. ISSN 0022-2585. 41(4), p. 752–752. doi: 10.1603/0022-2585-41.4.746. Full text in Research Archive Show summary

  Environmental risk factors associated with increased malaria mosquito (Anopheles) abundance indoors were studied in a suburban area, Antula, of Guinea Bissau, during the rainy seasons of 1993-1995. All bedrooms in 30 houses were searched for resting mosquitoes three times each year. The most abundant mosquito was An. gambiae s.s. Significantly greater numbers of resting mosquitoes were present in rooms with open eaves and in houses with a well on the compound. Pigs were the most common domestic animals in Antula. Presence of pigs in a house was associated with increased mosquito abundance in the bedrooms of the same house. The abundance of female mosquitoes also increased with increasing human biomass per square meter of bedroom area.

• Laugen, Ane Timenes; Laurila, A.; Räsänen, K. & Merilä, J. (2003). Latitudinal countergradient variation in the common frog (<i>Rana temporaria</i>) development rates – evidence for local adaptation. Journal of Evolutionary Biology. ISSN 1010-061X. 16(5), p. 1005–1005. doi: 10.1046/j.1420-9101.2003.00560.x. Full text in Research Archive Show summary

  Abstract Adaptive genetic differentiation along a climatic gradient as a response to natural selection is not necessarily expressed at phenotypic level if environmental effects on population mean phenotypes oppose the genotypic effects. This form of cryptic evolution – called countergradient variation – has seldom been explicitly demonstrated for terrestrial vertebrates. We investigated the patterns of phenotypic and genotypic differentiation in developmental rates of common frogs (Rana temporaria) along a ca. 1600 km latitudinal gradient across Scandinavia. Developmental rates in the field were not latitudinally ordered, but displayed large variation even among different ponds within a given latitudinal area. In contrast, development rates assessed in the laboratory increased strongly and linearly with increasing latitude, suggesting a genetic capacity for faster development in the northern than the southern larvae. Experiments further revealed that environmental effects (temperature and food) could easily override the genetic effects on developmental rates, providing a possible mechanistic explanation as to why the genetic differentiation was not seen in the samples collected from the wild. Our results suggest that the higher developmental rates of the northern larvae are likely to be related to selection stemming from seasonal time constrains, rather than from selection dictated by low ambient temperatures per se. All in all, the results provide a demonstration of environmental effects concealing substantial latitudinally ordered genetic differentiation understandable in terms of adaptation to clinal variation in time constrains.

• Palo, J. U.; O'Hara, R. B.; Laugen, Ane Timenes; Laurila, A.; Primmer, C. R. & Merilä, J. (2003). Latitudinal divergence of common frog (<i>Rana temporaria</i>) life history traits by natural selection: evidence from a comparison of molecular and quantitative genetic data. Molecular Ecology. ISSN 0962-1083. 12(7), p. 1963–1978. doi: 10.1046/j.1365-294x.2003.01865.x. Full text in Research Archive Show summary

  Abstract The relative roles of natural selection and direct environmental induction, as well as of natural selection and genetic drift, in creating clinal latitudinal variation in quantitative traits have seldom been assessed in vertebrates. To address these issues, we compared molecular and quantitative genetic differentiation between six common frog ( Rana temporaria ) populations along an approximately 1600 km long latitudinal gradient across Scandinavia. The degree of population differentiation ( Q ST  ≈ 0.81) in three heritable quantitative traits (age and size at metamorphosis, growth rate) exceeded that in eight (neutral) microsatellite loci ( F ST  = 0.24). Isolation by distance was clear for both neutral markers and quantitative traits, but considerably stronger for one of the three quantitative traits than for neutral markers. Q ST estimates obtained using animals subjected to different rearing conditions (temperature and food treatments) revealed some environmental dependency in patterns of population divergence in quantitative traits, but in general, these effects were weak in comparison to overall patterns. Pairwise comparisons of F ST and Q ST estimates across populations and treatments revealed that the degree of quantitative trait differentiation was not generally predictable from knowledge of that in molecular markers. In fact, both positive and negative correlations were observed depending on conditions where the quantitative genetic variability had been measured. All in all, the results suggest a very high degree of genetic subdivision both in neutral marker genes and genes coding quantitative traits across a relatively recently (< 9000 years) colonized environmental gradient. In particular, they give evidence for natural selection being the primary agent behind the observed latitudinal differentiation in quantitative traits.

• Laugen, Ane Timenes; Laurila, Anssi & Merilä, Juha (2003). Latitudinal and temperature-dependent variation in embryonic development and growth in Rana temporaria. Oecologia. ISSN 0029-8549. 135(4), p. 554–554. doi: 10.1007/s00442-003-1229-0. Full text in Research Archive Show summary

  Variation in seasonal time constraints and temperature along latitudinal gradients are expected to select for life history trait differentiation, but information about the relative importance of these factors in shaping patterns of divergence in embryonic traits remains sparse. We studied embryonic survival, growth and development rates in the common frog (Rana temporaria) along a 1,400-km latitudinal gradient across Sweden by raising embryos from four populations in the laboratory at seven temperatures (9°C, 12°C, 15°C, 18°C, 21°C, 24°C, 27°C). We found significant differences in mean values of all traits between the populations and temperature treatments, but this variation was not latitudinally ordered. In general, embryonic survival decreased at the two highest temperatures in all populations, but less so in the southernmost as compared to the other populations. The northernmost population developed slowest at the lowest temperature, while the two mid-latitude populations were slowest at the other temperatures. Hatchling size increased with increasing temperature especially in the two northern populations, whereas the two southern populations showed peak hatchling size at 15°C. Analyses of within-population genetic variation with a half-sib design revealed that there was significant additive genetic variation in all traits, and egg size-related maternal effects were important in the case of hatchling size. Overall, our results indicate that unlike larval growth and development, variation in embryonic development and growth in R. temporaria cannot be explained in terms of a latitudinal gradient in season length. While adaptation to a latitudinal variation in temperature might have contributed to the observed differentiation in embryonic performance, the effects of other, perhaps more local environmental factors, seem to have overridden them in importance.

• Laugen, Ane Timenes; LAURILA, ANSSI & Merilä, Juha (2002). Maternal and genetic contributions to geographical variation in Rana temporaria larval life-history traits. Biological Journal of the Linnean Society. ISSN 0024-4066. 76(1), p. 70–70. doi: 10.1111/j.1095-8312.2002.tb01714.x. Full text in Research Archive
• Merilä, Juha; Laurila, Anssi; Laugen, Ane Timenes; Räsänen, Katja & Pahkala, Maarit (2000). Plasticity in age and size at metamorphosis in <i>Rana temporaria</i> ‐ comparison of high and low latitude populations. Ecography. ISSN 0906-7590. 23(4), p. 465–465. doi: 10.1111/j.1600-0587.2000.tb00302.x. Full text in Research Archive Show summary

  Effects of different combinations of stressors (viz. temperature, food level) on growth, developmental and survival rates of Rana temporaria tadpoles from two geographically widely (∼ 1500 km) separated populations were studied in a common garden experiment. In both populations, low temperature and low food level lead to towered growth rates and delayed metamorphosis, whereas high temperature and high food level had the opposite effect. Tadpoles from north metamorphosed earlier and exhibited higher growth rates than tadpoles from south, suggesting local adaptation to shorter growth period and cooler ambient temperature in north. Size at metamorphosis did not differ between the two populations, but when the differences in metamorphic age were accounted for, then the tadpoles from north were larger than those from south. These results suggest considerable adaptive genetic differentiation in growth rates, size and timing of metamorphosis between northern and southern R. temporaria populations. In both populations, high food levels tended to reduce tadpole survival rates and there was a negative correlation between growth and survival rates across different treatments in both populations. In general, tadpoles from north experienced high mortality rates in high food level ‐ low temperature treatments, whereas southern tadpoles experienced high mortality in high food level‐high temperature treatments. This suggest that there may be genetic differences among different populations as how they would be influenced by high nutrient loads, such as brought along for example by fertilization of forest or agricultural soils.

• Merilä, Juha; Laurila, Anssi; Pahkala, Maarit; Räsänen, Katja & Laugen, Ane Timenes (2000). Adaptive phenotypic plasticity in timing of metamorphosis in the common frog Rana temporaria. Écoscience. ISSN 1195-6860. 7(1), p. 24–24. doi: 10.1080/11956860.2000.11682566. Full text in Research Archive Show summary

  Unpredictable environments are expected to select for adaptive plasticity in traits enabling adjustment of phenotype to prevailing environmental conditions. Common frogs (Rana temporaria) breed frequently in ponds, which dry up before the aquatic larvae have metamorphosed, and consequently, plasticity in timing of metamorphosis in response to pond drying could be adaptive. We investigated the responses of half- and full-sib R. temporaria larvae to simulated pond drying in a factorial experiment to test whether there is adaptive phenotypic plasticity in timing of metamorphosis, and whether this plasticity is genetically determined. As expected under the adaptive hypothesis, we found that larvae exposed to the decreasing water treatment metamorphosed significantly faster than their sibs in the constant water treatments. Furthermore, age and size at metamorphosis were positively correlated in the constant water treatments, but negatively correlated in the decreasing water treatment. However, larvae from decreasing water treatment metamorphosed, on average, at a smaller size as compared to larvae from the constant water treatments, even after controlling for variation in developmental time. Since smaller size at metamorphosis is likely to be related to reduced fitness, this indicates that faster development may trade off with other components of fitness. The results further show that the amount of food received during the four first days of development influenced age and size at metamorphosis, reinforcing the view that early life nutrition may have a significant impact on later life fitness. Although there was a genetic component to developmental rates, we found no evidence for genetic variation in plasticity. In accordance with evidence from other studies, our results suggest existence of adaptive phenotypic plasticity in amphibian development.

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• Reamon, Molly Claire & Laugen, Ane Timenes (2024). En østers er en østers er en østers, eller... Full text in Research Archive
• Laugen, Ane Timenes; Reamon, Molly Claire & Mortensen, Stein (2024). Et steg i feil retning. Full text in Research Archive
• Lien, Anne; Larsen, Jorunn; Nygård, Malene Østreng; Gabrielsen, Tove M.; Korslund, Lars & Marcussen, Johanna Bjånes [Show all 10 contributors for this article] (2024). Gimle: En gressplen erstatter ikke skog. p. 15–15. Full text in Research Archive
• Lien, Anne; Nygård, Malene Østreng; Laugen, Ane Timenes; Lie, Asbjørn; Slettan, Audun & Johansen, Beate Strøm [Show all 33 contributors for this article] (2023). Utbygging vil ødelegge for biologisk mangfold på campus Gimlemoen. NB! 34 forfattere totalt. p. 19–19. Full text in Research Archive
• Marcussen, Johanna Bjånes; Hjelset, Ann Merete; Zimmermann, Fabian; Søvik, Guldborg; Laugen, Ane Timenes & Hvingel, Carsten (2023). Spatiotemporal cross-validation of three survey methods for improved abundance indices of red king crab (Paralithodes camtschaticus). Full text in Research Archive Show summary

  Sustainable fisheries require input data of sufficient quantity and quality to inform stock assessments and management. However, capacity and resources to collect data are limited, underlining the need for methods that can maximize the utility of available fisheries-independent and -dependent data. The goal is to improve estimates of stock size and uncertainty, even from time series with inconsistent coverage and gear changes. This is of particular concern for the many stocks that are defined as datalimited, especially many shellfish stocks that are often not sufficiently covered by regular scientific surveys due to poor catchability in standard bottom trawls or habitat mismatch. This creates the need for methods that improve the coverage of such species by extracting and integrating information from available data. Additionally, the integration of data from different sources could prevent disjointed and potentially contradicting indices, especially when new survey methods are implemented parallel to existing surveys. Furthermore, combining already available data from surveys using differing gear types represents a cost-effective use of data and reduces the need for specialized surveys for target species. However, ahead of any consolidation of data from different surveys or gear types, information from different gears needs to be compared and, if possible, calibrated against each other. The red king crab survey in northern Norway provides an experimental setup with nearby stations to assess the catchability of bottom trawl, pots, and video. How well bottom trawls catch king crab is uncertain, and direct observations from video-based surveys and pots comparable to those used in commercial fishing may be more suitable approaches to assess changes in abundance. Interest in less intrusive survey methods has been heightened by concern for habitats that are vulnerable to damage caused by destructive sampling devices such as trawls. Visual surveys have emerged as a promising method for surveying benthic resources. We will present how observed densities and catch compositions of red king crab compare across survey gear, and how information from different gear types can be combined in an integrated estimation of abundance indices. We find common trends across gear types but also highlight challenges linked to substantial spatial variation in a highly structured fjord ecosystem. The results of this case study contribute novel insights into the integration of different data sources and gear types into coherent estimates of abundance indices and their uncertainty to facilitate implementation of new survey methods.

• Marcussen, Johanna Bjånes; Reamon, Molly Claire; Mortensen, Stein & Laugen, Ane Timenes (2023). I Rogaland er det fremdeles håp for flatøstersen. Full text in Research Archive
• Marcussen, Johanna Bjånes; Hjelset, Ann Merete; Danielsen, Hanna Ellerine Helle; Hvingel, Carsten; Søvik, Guldborg & Laugen, Ane Timenes [Show all 7 contributors for this article] (2023). Spatiotemporal cross-validation of three survey methods for improved abundance indices of red king crab (Paralithodes camtschaticus). Full text in Research Archive
• Laugen, Ane Timenes (2023). Styggpen, knivskarp og delvis brukbar. Full text in Research Archive
• Laugen, Ane Timenes (2022). Stillehavsøsters — vesentlig bedre enn havnespy. Full text in Research Archive
• Laugen, Ane Timenes (2021). #stillehavsøsters #lovehate. Full text in Research Archive
• Laugen, Ane T (2020). Siste nytt på nettverksfronten; SNOK, MarGen II & NORA. Full text in Research Archive
• Laugen, Ane T (2019). Bivalvdynamikk i kystsonen – håndtering av stillehavsøsters og bevaring av flatøsters og blåskjell. Full text in Research Archive
• Laugen, Ane T & Strand, Åsa (2019). Threats to blue mussels 
— a European risk analysis. Full text in Research Archive
• Laugen, Ane T; Obst, Matthias & Strand, Åsa (2019). Pacific oysters in Scandinavian waters; harvesting potential and impact on local bivalves. Full text in Research Archive Show summary

  The Pacific oyster (Magallana gigas) is not only one of the world’s most utilised aquaculture species; it is also extremely apt at establishing feral populations in areas to which it has been introduced. Moreover, the relative ease by which it expands its geographical range outside original introduction sites makes it a highly successful invader. Since 2006 the Skagerrak coastlines have established, self-sustaining, Pacific oyster stocks of millions of individuals and their range is expanding northwards along the Norwegian west coast and southwards towards the Baltic Sea. Our 2007-2019 time series from western Sweden show that the Pacific oysters experience low levels of predation, survive heavy winters, and bounce back from disease. Additionally, the Scandinavian Pacific oyster stocks are underused commercially. Populations are therefore free to grow without many constraints. While effects are not uniformly negative, a number of stakeholders are concerned about impacts on local coastal-zone bivalves. To quantify the potential overlap between M. gigas and local bivalves we used an ecological niche modelling approach to 1) estimate current habitat availability for, 2) detect current niche overlap between, and 3) predict future suitable habitat of the invasive M. gigas and the European species Ostrea edulis and Mytilus spp. Most importantly, we found major overlap between the current theoretical niches of M. gigas and O. edulis, which warrants further field-based investigations to determine the degree to which their current realised niches overlap and associated consequences. Moreover, we urgently need to solve a number of challenges that currently limit the degree to which Pacific oysters are harvested commercially.

• Laugen, Ane T; Strand, Åsa; Naustvoll, Lars Johan; Dolmer, Per & Mortensen, Stein (2019). Hurdles and possibilities for management of the invasive Pacific oyster in Scandinavia using small-scale fisheries. Full text in Research Archive Show summary

  Since 2006, the Pacific oyster has established self-sustaining populations in Scandinavian coastal waters. The species is considered invasive and dense populations may cause changes to coastal ecosystems. The species is, however, also of high economic value and there is a growing interest from the aquaculture and fisheries industry to realize the potential of this species as a new marine resource in Scandinavia. Activities receiving increasing attention are gastronomic tourism, harvest of wild oyster populations and aquaculture, activities that may provide income in rural areas and support local communities. The commercialization of wild Pacific oysters in Scandinavia is, however, limited by several regulatory and policy related hurdles connected to ownership of the resource, food safety issues and management of invasive species. There are also conflicting management objectives within authorities as legislation is not fully integrated between different domains. To address these hurdles, a Scandinavian oyster network was formed in 2013 to allow formation of a joint knowledge platform, dissemination of relevant management initiatives to relevant stakeholders and co-creation of innovative management alternatives based on requests from industry and governmental authorities. One alternative currently under investigation is utilization of commercial interests to provide management of selected areas of special concern where the impact of the Pacific oyster may cause the most severe effects. In this poster, the work performed within the Scandinavian network and the resulting conclusions recently presented in a Policy brief released by the Nordic Council of Ministers will be highlighted and discussed.

• Laugen, Ane T (2019). #stillehavsøsters 
#lovehate. Full text in Research Archive
• Laugen, Ane T (2019). Stillehavsøsters — muligheter og utfordringer. Full text in Research Archive
• Mortensen, Stein; Bøgwald, Mats; Strohmeier, Tore; Strand, Øivind; Larsson, Sigmund B. & Laugen, Ane Timenes [Show all 8 contributors for this article] (2023). Kartlegging av østersbestander i Rogaland i 2021 og 2023 - innsamling av data som grunnlag for bestandsforvaltning. Havforskningsinstituttet. Full text in Research Archive Show summary

  Flatøstersen, Ostrea edulis, er utbredt fra Marokko i syd, i Middelhavet, Svartehavet og langs kysten av Europa, nord til Vest-Norge. I det meste av utbredelsesområdet er bestandene kraftig redusert på grunn av overhøsting, ødeleggelse av østersbanker i forbindelse med høsting og dødelighet forårsaket av parasittsykdommene bonamiose og marteiliose. Det arbeides nå med å kartlegge og bevare de siste intakte bestandene i Europa, og det gjøres flere forsøk på å restaurere opprinnelige bestander. Havforskningsinstituttet og Universitetet i Agder har de siste årene kartlagt og beskrevet norske østersbestander. Formålet med arbeidet som er beskrevet i denne rapporten var å kartlegge flatøstersbestandene i Rogaland og beskrive bestandene i Hafrsfjord ved Stavanger og Haugavågen på Karmøy. Resultatene viser at noen av flatøstersbestandene i Rogaland er unike, og kan representere donorbestander som er sentrale i å opprettholde lokale flatøstersbestander og spre larver til omliggende områder. Disse lokalitetene har kanskje Europas nordligste og mest intakte, sykdomsfrie og naturlig reproduserende flatøstersbestander. Prosjektene har samlet inn data som kan bidra til å legge grunnlaget for forvaltning av bestandene og beskyttelse av disse mot overhøsting eller habitatforringelse.

• Mortensen, Stein; Laugen, Ane T; Strand, Åsa; Dolmer, Per; Naustvoll, Lars Johan & Jelmert, Anders [Show all 13 contributors for this article] (2022). Stillehavsøsters i Norden. Datainnsamling og bestandsvurderinger som grunnlag for forvaltning og høsting av nordiske bestander av stillehavsøsters, Crassostrea gigas. Nordisk ministerråd. ISSN 9789289372398. doi: 10.6027/temanord2022-504. Full text in Research Archive
• Laugen, Ane Timenes (1998). Do male bluethroats (Luscinia s. svecica) sing to advertise parental abilities? [Mangler utgivernavn]. Full text in Research Archive

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