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Query: "author" (Marjana Westergren) .

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Ohranjanje gozdnih genskih virov : tehnične smernice za ohranjanje in rabo genskih virov: Slovenija
Hojka Kraigher, Marjana Westergren, 2010, preface, editorial, afterword

Keywords: genski viri, drevesne vrste, tehnične smernice
Published in DiRROS: 12.12.2023; Views: 168; Downloads: 41
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Low but significant evolutionary potential for growth, phenology and reproduction traits in European beech
Marjana Westergren, Juliette Archambeau, Marko Bajc, Rok Damjanić, Adélaïde Theraroz, Hojka Kraigher, Sylvie Oddou-Muratorio, Santiago C. González-Martínez, 2023, original scientific article

Abstract: Local survival of forest tree populations under climate change depends on existing genetic variation and their adaptability to changing environments. Responses to selection were studied in European beech (Fagus sylvatica) under field conditions. A total of 1087 adult trees, seeds, 1-year-old seedlings and established multiyear saplings were genotyped with 16 nuSSRs. Adult trees were assessed for phenotypic traits related to growth, phenology and reproduction. Parentage and paternity analyses were used to estimate effective female and male fecundity as a proxy of fitness and showed that few parents contributed to successful regeneration. Selection gradients were estimated from the relationship between traits and fecundity, while heritability and evolvability were estimated using mixed models and the breeder's equation. Larger trees bearing more fruit and early male flowering had higher total fecundity, while trees with longer growth season had lower total fecundity (directional selection). Stabilizing selection on spring phenology was found for female fecundity, highlighting the role of late frosts as a selection driver. Selection gradients for other traits varied between measurement years and the offspring cohort used to estimate parental fecundity. Compared to other studies in natural populations, we found low to moderate heritability and evolvability for most traits. Response to selection was higher for growth than for budburst, leaf senescence or reproduction traits, reflecting more consistent selection gradients across years and sex functions, and higher phenotypic variability in the population. Our study provides empirical evidence suggesting that populations of long-lived organisms such as forest trees can adapt locally, even at short-time scales.
Keywords: climate change, Fagus sylvatica, heritability, in situ adaptation, response to selection, selection gradients
Published in DiRROS: 12.12.2023; Views: 192; Downloads: 88
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Between but not within-species variation in the distribution of fitness effects
Jennifer James, Chedly Kastallya, Katharina Budde, Santiago C. González-Martínez, Pascal Milesi, Tanja Pyhäjärvi, Martin Lascoux, 2023, original scientific article

Abstract: New mutations provide the raw material for evolution and adaptation. The distribution of fitness effects (DFE) describes the spectrum of effects of new mutations that can occur along a genome, and is, therefore, of vital interest in evolutionary biology. Recent work has uncovered striking similarities in the DFE between closely related species, prompting us to ask whether there is variation in the DFE among populations of the same species, or among species with different degrees of divergence, that is whether there is variation in the DFE at different levels of evolution. Using exome capture data from six tree species sampled across Europe we characterized the DFE for multiple species, and for each species, multiple populations, and investigated the factors potentially influencing the DFE, such as demography, population divergence, and genetic background. We find statistical support for the presence of variation in the DFE at the species level, even among relatively closely related species. However, we find very little difference at the population level, suggesting that differences in the DFE are primarily driven by deep features of species biology, and those evolutionarily recent events, such as demographic changes and local adaptation, have little impact.
Keywords: DFE, deleterious mutations, population structure, forest trees
Published in DiRROS: 12.12.2023; Views: 220; Downloads: 94
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Infestation intensity by the invasive oak lace bug, Corythucha arcuata (Say) in mixed and pure oak stands
Gernot Hoch, Alex Stemmelen, Eötvös Csaba Béla, Werner Hinterstoisser, Miran Lanšćak, Srđan Stojnić, Máté Tóth, Marjana Westergren, Simon Zidar, Milica Zlatković, Nikola Zoric, Maarten De Groot, 2024, original scientific article

Abstract: There has been accumulating evidence for effects of tree species composition on herbivory with many examples of lower damage by specialist feeders in tree species rich forests. In a joint study in five Central and Southeastern European countries, we studied the effect of tree species richness on infestation intensity of the oak lace bug, Corythucha arcuata (Say) (Heteroptera, Tingidae), an invasive pest on oak trees that has spread rapidly across the Balkan Peninsula and Central Europe. Intensity of infestation by C. arcuata on oaks was assessed on three or four study plots with high (pure stands) and three or four plots with low percentage of oak (mixed stands) in each country. Ordinal regression analysis showed that intensity of infestation of trees by C. arcuata differed between countries; no significant effect of stand type (mixed or pure) on infestation levels was detected. When analysing the percentage of trees in the highest infestation class, stand type had a significant effect with more intensive infestation in pure stands. We conclude that mixed stands will not prevent severe infestation but may help mitigating the impact of established C. arcuata populations.
Keywords: associational resistance, Corythucha arcuata, diversity, host tree concentration, invasive forest pest
Published in DiRROS: 14.11.2023; Views: 289; Downloads: 174
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Forest managers’ perspectives on environmental changes in the biosphere reserve Mura-Drava-Danube
Marcus Sallmannshofer, Rok Damjanić, Harald Vacik, Marjana Westergren, Tjaša Baloh, Gregor Božič, Mladen Ivanković, Gyula Kovács, Miran Lanšćak, Katharina Lapin, Laszlo Nagy, Silvija Krajter Ostoić, Saša Orlović, Srđan Stojnić, Peter Železnik, Milica Zlatković, Silvio Schueler, 2023, original scientific article

Abstract: Riparian forests are particularly vulnerable to environmental change and anthropogenic influences because they are highly dynamic ecosystems, thus proper adaptation measures are crucial. The implementation of these measures, however, strongly depends on the actors’ perceptions of the specific problems occurring in such forests. For understanding the constraints of specific interest groups toward different adaptation activities, information in this field is essential. By conducting a questionnaire survey we explore how different types of forest managers, i.e., forestry professionals, forest owners, and conservation managers, perceive the effects of environmental change on forest management in the recently established Transboundary Biosphere Reserve Mura-Drava-Danube. We show that these forest managers are highly aware of ongoing environmental changes and appraise deteriorating forest conditions, especially after observing changes themselves. Abiotic damage is expected to increase the most, followed by biotic damage, the spread of non-native species, and tree dieback. Nearly 80% of the survey respondents expect further changes and almost all of them intend to adapt their management of forests to mitigate or prepare for these changes. Nevertheless, we show differences in sensitivity to change and willingness to initiate adaptation actions by assessing adaptation thresholds: conservation managers appear generally more tolerant to changes, which results in higher thresholds to initiate management adaptation than forestry professionals
Keywords: biosphere reserve Mura-Drava-Danube, forest management, sensitivity to environmental change, stakeholder perception, adaptation thresholds, riparian forest tree species
Published in DiRROS: 31.05.2023; Views: 341; Downloads: 267
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Gene sequence variation data for the publication "Synchronous effective population size changes and genetic stability of forest trees through glacial cycles" : version 1.0
Tanja Pyhäjärvi, Francesca Bagnoli, Katharina Budde, Stephen Cavers, Sandra Cervantes, Benjamin Dauphin, Bruno Fady, Patricia Faivre-Rampant, Santiago C. González-Martínez, Delphine Grivet, Felix Gugerli, Véronique Jorge, Chedly Kastallya, Martin Lascoux, Isabelle Lesur Kupin, Pascal Milesi, Dario I. Ojeda, Sanna Olsson, Lars Opgenoorth, Sara Pinosio, Christophe Plomion, Christian Rellstab, Odile Rogier, Simone Scalabrin, Ivan Scotti, Giovanni G Vendramin, Marjana Westergren, 2023, complete scientific database of research data

Abstract: This dataset contains the gene sequence variation data (vcf files and their tbi index files) of seven forest tree species used in the manuscript "Synchronous effective population size changes and genetic stability of forest trees through glacial cycles". For each species, between 411 and 651 genotyped trees are included, sampled across Europe in at least 20 locations. Several versions are provided. Species included: Pinus sylvestris, Picea abies, Fagus sylvatica, Populus nigra, Quercus petraea, Pinus pinaster, Betula pendula
Keywords: gene sequence, variation data, data set
Published in DiRROS: 07.03.2023; Views: 546; Downloads: 548
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