Tree defense in a changing world
Ecology and Biodiversity of Plants and Ecosystems
Final Report Abstract
The main objective of the project was to elucidate interactions between stress and defense physiology in trees in the context of their susceptibility against biotic attack. During environmental stress changes in tree physiology may cause of increased vulnerability against biotic attack, yet, the underlying mechanism have not been quantified, making predictions of future tree mortality highly uncertain. In work package one, we evaluated the linkage between tree primary and secondary metabolism during drought. Taking advantage of already existing drought experiment, we collected 3000 samples from seven countries, on three continents and quantified relationships between concentrations of non-structural carbohydrates (NSC, primary metabolites) and defense compounds (secondary metabolites, SM), as predictors of tree vulnerability to insect damage and disease. We found that allocation to SM tended to increase during drought in temperate and subtropical regions, but not in drylands or in the tropics. We are currently synthesizing results of NSCs and examining their relationships to SMs under drought. In work package two, we investigated the impact of physiological stress in Norway spruce trees on tree vitality and emissions of volatile organic compound (VOC). Our hypotheses were that a decline in vitality induces changes in VOC profiles emitted from tree stems and that these changes may be used by damaging insects as cues for host selection. We found that stem tissues of windthrown Norway spruce trees showed indication of reduced tree vitality – with lower concentrations of both primary and secondary metabolites. Stressed trees had different stem-emitted VOC profiles; emission rates of monoterpenes were remarkably higher in windthrown than in standing trees, in particular in some monoterpene species. We concluded that these changes in VOC emissions could serve bark beetles as a cue for detecting less vital trees. To verify this assumption, we investigated in work package three changes in beetle behavior. In a laboratory study, we evaluated the attraction of bark beetles to bark pieces of standing and windthrown trees. These assay choice tests did not provide a strong evidence for beetle attraction towards bark pieces of windthrown trees; however, it seemed that more advanced testing using controlled emissions of the monoterpene species identified in work package two may be better suited to verify the role of VOC as olfactory cues. Taken together, our study results provide a better understanding of tree defense responses during environmental stress and will contribute to improving the predictive capacity of vegetation models.
Publications
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VOC emission in spruce as cause for bark beetle host selection. GFÖ virtual meeting, Vortrag.
Lehmanski, L. M. A., Kunz, L., Gershenzon, J. & Hartmann, H.
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How to find the right host - Olfactory signals as cues in bark beetle host selectoion. Poster. SFE2 GFÖ EEF - International Conference on Ecological Sciences, Metz, Frankreich, Poster.
Lehmanski, L. M. A., Werner, M., Göbel, M., Lambert, S. & Hartmann, H.
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The scent of easy prey- The importance of olfactory signals in bark beetle host selection. IUFRO all Division 7 "Forest Health", Lissabon, Portugal, Vortrag.
Lehmanski, L. M. A., Werner, M., Göbel, M., Lambert, S. & Hartmann, H.
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Volatile emissions in spruce could act as cues for bark beetle host selection. EGU General Assembly, Wien, Östereich, Vortrag.
Lehmanski, L. M. A. & Hartmann, H.
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Addressing a century‐old hypothesis – do pioneer beetles of Ips typographus use volatile cues to find suitable host trees?. New Phytologist, 238(5), 1762-1770.
Lehmanski, Linda M. A.; Kandasamy, Dineshkumar; Andersson, Martin N.; Netherer, Sigrid; Alves, Eliane Gomes; Huang, Jianbei & Hartmann, Henrik
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How to find the right host - Primary attraction and host selection of the bark beetles Ips typographus. European Congress of Entomology, Heraklion, Griechenland, Poster.
Lehmanski, L. M. A.
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Opfer gesucht – Duftstoffsignale weisen dem Buchdrucker Ips typographus den Weg zu geeigneten Wirtsbäumen. Fowissenschaftliche Tagung (FowiTa), Dresden, Deutschland, Vortrag.
Lehmanski, L. M. A.
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Primary attraction in Ips typographus - New avenues to reduce the spread of pioneer beetles. IUFRO, Global Challenges and Innovative Management of Bark and Wood Borers in Planted Forests, Bordeaux, Frankreich, Vortrag.
Lehmanski, L. M. A.
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Windthrow causes declines in carbohydrate and phenolic concentrations and increased monoterpene emission in Norway spruce. PLOS ONE, 19(5), e0302714.
Lehmanski, Linda M. A.; Kösters, Lara M.; Huang, Jianbei; Göbel, Martin; Gershenzon, Jonathan & Hartmann, Henrik
