| 11. |
- Jónsdóttir, I. S., et al.
(author)
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Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming
- 2022
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In: Ecological Monographs. - : Wiley. - 0012-9615 .- 1557-7015.
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Journal article (peer-reviewed)abstract
- In the high Arctic, plant community species composition generally responds slowly to climate warming, whereas less is known about the community functional trait responses and consequences for ecosystem functioning. Slow species turnover and large distribution ranges of many Arctic plant species suggest a significant role of intraspecific trait variability in functional responses to climate change. Here, we compare taxonomic and functional community compositional responses to a long-term (17years) warming experiment in Svalbard, replicated across three major high Arctic habitats shaped by topography and contrasting snow regimes. We observed taxonomic compositional changes in all plant communities over time. Still, responses to experimental warming were minor and most pronounced in the drier habitats with relatively early snowmelt timing and long growing seasons (Cassiope and Dryas heaths). The habitats were clearly separated in functional trait space, defined by twelve size- and leaf economics-related traits, primarily due to interspecific trait variation. Functional traits also responded to experimental warming, most prominently in the Dryas heath and mostly due to intraspecific trait variation. Leaf area and leaf mass increased, and leaf δ15N decreased in response to the warming treatment. Intraspecific trait variability ranged between 30% and 71% of the total trait variation, reflecting functional resilience of those communities, dominated by long-lived plants, due to either phenotypic plasticity or genotypic variation that most likely underlies the observed resistance of high Arctic vegetation to climate warming. We further explored the consequences of trait variability for ecosystem functioning by measuring peak season CO2 fluxes. Together, environmental, taxonomic, and functional trait variables explained a large proportion of the variation in net ecosystem exchange (NEE), which increased when intraspecific trait variation was accounted for. In contrast, even though ecosystem respiration and gross ecosystem production both increased in response to warming across habitats, they were mainly driven by the direct kinetic impacts of temperature on plant physiology and biochemical processes. Our study shows that long-term experimental warming has a modest but significant effect on plant community functional trait composition and suggests that intraspecific trait variability is a key feature underlying high Arctic ecosystem resistance to climate warming.
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| 14. |
- Sarneel, Judith M., et al.
(author)
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Reading tea leaves worldwide : decoupled drivers of initial litter decomposition mass-loss rate and stabilization
- 2024
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In: Ecology Letters. - : John Wiley & Sons. - 1461-023X .- 1461-0248. ; 27:5
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Journal article (peer-reviewed)abstract
- The breakdown of plant material fuels soil functioning and biodiversity. Currently, process understanding of global decomposition patterns and the drivers of such patterns are hampered by the lack of coherent large-scale datasets. We buried 36,000 individual litterbags (tea bags) worldwide and found an overall negative correlation between initial mass-loss rates and stabilization factors of plant-derived carbon, using the Tea Bag Index (TBI). The stabilization factor quantifies the degree to which easy-to-degrade components accumulate during early-stage decomposition (e.g. by environmental limitations). However, agriculture and an interaction between moisture and temperature led to a decoupling between initial mass-loss rates and stabilization, notably in colder locations. Using TBI improved mass-loss estimates of natural litter compared to models that ignored stabilization. Ignoring the transformation of dead plant material to more recalcitrant substances during early-stage decomposition, and the environmental control of this transformation, could overestimate carbon losses during early decomposition in carbon cycle models.
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| 18. |
- Jonsdottir, Björg, et al.
(author)
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Preoperative and intraoperative assessment of myometrial invasion in endometrial cancer—A Swedish Gynecologic Cancer Group (SweGCG) study
- 2021
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In: Acta Obstetricia et Gynecologica Scandinavica. - : Wiley. - 0001-6349 .- 1600-0412. ; 100:8, s. 1526-1533
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Journal article (peer-reviewed)abstract
- Introduction: Deep myometrial invasion (≥50%) is a prognostic factor for lymph node metastases and decreased survival in endometrial cancer. There is no consensus regarding which pre/intraoperative diagnostic method should be preferred. Our aim was to explore the pattern of diagnostic methods for myometrial invasion assessment in Sweden and to evaluate differences among magnetic resonance imaging (MRI), transvaginal sonography, frozen section, and gross examination in clinical practice. Material and methods: This is a nationwide historical cohort study; women with endometrial cancer with data on assessment of myometrial invasion and FIGO stage I-III registered in the Swedish Quality Registry for Gynecologic Cancer (SQRGC) between 2017 and 2019 were eligible. Data on age, histology, FIGO stage, method, and results of myometrial invasion assessment, pathology results, and hospital level were collected from the SQRGC. The final assessment by the pathologist was considered the reference standard. Results: In the study population of 1401 women, 32% (n=448) had myometrial invasion of 50% of more. The methods reported for myometrial invasion assessment were transvaginal sonography in 59%, MRI in 28%, gross examination in 8% and frozen section in 5% of cases. Only minor differences were found for age and FIGO stage when comparing methods applied for myometrial invasion assessment. The sensitivity, specificity, and accuracy to find myometrial invasion of 50% or more with transvaginal sonography were 65.6%, 80.3%, and 75.8%, for MRI they were 76.9%, 71.9%, and 73.8%, for gross examination they were 71.9%, 93.6%, and 87.3%, and for frozen section they were 90.0%, 92.7%, and 92.0%, respectively. Conclusions: In Sweden, the assessment of deep myometrial invasion is most often performed with transvaginal sonography, but the sensitivity is lower than for the other diagnostic methods. In clinical practice, the accuracy is moderate for transvaginal sonography and MRI. © 2021 The Authors. Acta Obstetricia et Gynecologica Scandinavica published by John Wiley & Sons Ltd on behalf of Nordic Federation of Societies of Obstetrics and Gynecology (NFOG)
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| 19. |
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| 20. |
- Lett, Signe, et al.
(author)
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Can bryophyte groups increase functional resolution in tundra ecosystems?
- 2022
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In: Arctic Science. - Ottawa : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 609-637
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Journal article (peer-reviewed)abstract
- The relative contribution of bryophytes to plant diversity, primary productivity, and ecosystem functioning increases towards colder climates. Bryophytes respond to environmental changes at the species level, but because bryophyte species are relatively difficult to identify, they are often lumped into one functional group. Consequently, bryophyte function remains poorly resolved. Here, we explore how higher resolution of bryophyte functional diversity can be encouraged and implemented in tundra ecological studies. We briefly review previous bryophyte functional classifications and the roles of bryophytes in tundra ecosystems and their susceptibility to environmental change. Based on shoot morphology and colony organization, we then propose twelve easily distinguishable bryophyte functional groups. To illustrate how bryophyte functional groups can help elucidate variation in bryophyte effects and responses, we compiled existing data on water holding capacity, a key bryophyte trait. Although plant functional groups can mask potentially high interspecific and intraspecific variability, we found better separation of bryophyte functional group means compared with previous grouping systems regarding water holding capacity. This suggests that our bryophyte functional groups truly represent variation in the functional roles of bryophytes in tundra ecosystems. Lastly, we provide recommendations to improve the monitoring of bryophyte community changes in tundra study sites.
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