| 1. |
- Alatalo, Juha M, 1966-, et al.
(författare)
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Testing reliability of short-term responses to predict longer-term responses of bryophytes and lichens to environmental change
- 2015
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X .- 1872-7034. ; 58, s. 77-85
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Tidskriftsartikel (refereegranskat)abstract
- Environmental changes are predicted to have severe and rapid impacts on polar and alpine regions. At high latitudes/altitudes, cryptogams such as bryophytes and lichens are of great importance in terms of biomass, carbon/nutrient cycling, cover and ecosystem functioning. This seven-year factorial experiment examined the effects of fertilizing and experimental warming on bryophyte and lichen abundance in an alpine meadow and a heath community in subarctic Sweden. The aim was to determine whether shortterm responses (five years) are good predictors of longer-term responses (seven years). Fertilizing and warming had significant negative effects on total and relative abundance of bryophytes and lichens, with the largest and most rapid decline caused by fertilizing and combined fertilizing and warming. Bryophytes decreased most in the alpine meadow community, which was bryophyte-dominated, and lichens decreased most in the heath community, which was lichen-dominated. This was surprising, as the most diverse group in each community was expected to be most resistant to perturbation. Warming alone had a delayed negative impact. Of the 16 species included in statistical analyses, seven were significantly negatively affected. Overall, the impacts of simulated warming on bryophytes and lichens as a whole and on individual species differed in time and magnitude between treatments and plant communities (meadow and heath). This will likely cause changes in the dominance structures over time. These results underscore the importance of longer-term studies to improve the quality of data used in climate change models, as models based on short-term data are poor predictors of long-term responses of bryophytes and lichens. (C) 2015 Elsevier Ltd. All rights reserved.
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| 2. |
- Alatalo, Juha M., et al.
(författare)
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Vascular plant abundance and diversity in an alpine heath under observed and simulated global change
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Global change is predicted to cause shifts in species distributions and biodiversity in arctic tundra. We applied factorial warming and nutrient manipulation to a nutrient and species poor alpine/arctic heath community for seven years. Vascular plant abundance in control plots increased by 31%. There were also notable changes in cover in the nutrient and combined nutrient and warming treatments, with deciduous and evergreen shrubs declining, grasses overgrowing these plots. Sedge abundance initially increased significantly with nutrient amendment and then declined, going below initial values in the combined nutrient and warming treatment. Nutrient addition resulted in a change in dominance hierarchy from deciduous shrubs to grasses. We found significant declines in vascular plant diversity and evenness in the warming treatment and a decline in diversity in the combined warming and nutrient addition treatment, while nutrient addition caused a decline in species richness. The results give some experimental support that species poor plant communities with low diversity may be more vulnerable to loss of species diversity than communities with higher initial diversity. The projected increase in nutrient deposition and warming may therefore have negative impacts on ecosystem processes, functioning and services due to loss of species diversity in an already impoverished environment.
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| 3. |
- Jägerbrand, Annika K., et al.
(författare)
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Effects of human trampling on abundance and diversity of vascular plants, bryophytes and lichens in alpine heath vegetation, Northern Sweden
- 2015
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Ingår i: SpringerPlus. - : Springer. - 2193-1801. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effects of human trampling on cover, diversity and species richness in an alpine heath ecosystem in northern Sweden. We tested the hypothesis that proximity to trails decreases plant cover, diversity and species richness of the canopy and the understory. We found a significant decrease in plant cover with proximity to the trail for the understory, but not for the canopy level, and significant decreases in the abundance of deciduous shrubs in the canopy layer and lichens in the understory. Proximity also had a significant negative impact on species richness of lichens. However, there were no significant changes in species richness, diversity or evenness of distribution in the canopy or understory with proximity to the trail. While not significant, liverworts, acrocarpous and pleurocarpous bryophytes tended to have contrasting abundance patterns with differing proximity to the trail, indicating that trampling may cause shifts in dominance hierarchies of different groups of bryophytes. Due to the decrease in understory cover, the abundance of litter, rock and soil increased with proximity to the trail. These results demonstrate that low-frequency human trampling in alpine heaths over long periods can have major negative impacts on lichen abundance and species richness. To our knowledge, this is the first study to demonstrate that trampling can decrease species richness of lichens. It emphasises the importance of including species-level data on non-vascular plants when conducting studies in alpine or tundra ecosystems, since they often make up the majority of species and play a significant role in ecosystem functioning and response in many of these extreme environments.
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| 4. |
- Levin, Lena, 1958-, et al.
(författare)
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Unpacking corrections in mobile instruction : Error-occasioned learning opportunities in driving, cycling and aviation training
- 2017
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Ingår i: Linguistics and Education. - : Elsevier BV. - 0898-5898 .- 1873-1864. ; 38, s. 11-23
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Tidskriftsartikel (refereegranskat)abstract
- This article deals with the organisation of correction in mobile instructional settings. Five sets of video data (>250 h) documenting how learners were instructed to fly aeroplanes, drive cars and ride bicycles in real life traffic were examined to reveal some common features of correction exchanges. Through detailed multimodal analysis of participants’ actions, it is shown how instructors systematically elaborate their corrective instructions to include relevant information about the trouble and remedial action – a practice we refer to as unpacking corrections. It is proposed that the practice of unpacking the local particulars of corrections (i) provides for the instructional character of the interaction, and (ii) is highly sensitive to the relevant physical and mobile contingencies. These findings contribute to the existing literature on the interactional organisation of correction and mobility, as well as to ongoing work in ethnomethodology and conversation analysis on teaching and learning as members’ phenomena.
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| 5. |
- Little, Chelsea J., et al.
(författare)
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Community and species-specific responses to simulated global change in two subarctic-alpine plant communities
- 2015
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Ingår i: Ecosphere. - : ESA. - 2150-8925 .- 2150-8925. ; 6:11
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Tidskriftsartikel (refereegranskat)abstract
- Long-term observational studies have detected greening and shrub encroachment in the subarctic attributed to current climate change, while global change simulations have showed that community composition and productivity may shift drastically in arctic, subarctic, and alpine tundra plant communities in the future. However, responses to global change can be highly species-and context-dependent. We examined community-level and species-specific responses to a six-year factorial temperature and nutrient (nitrogen and phosphorus) amendment experiment in two alpine plant communities in northern Sweden: a species-poor dwarf shrub heath, and a more species-rich meadow. We hypothesized that abundance responses to global change would be variable within commonly defined vascular plant functional groups (e.g., forbs, evergreen shrubs, deciduous shrubs) and that new species would appear in experimental plots over time due to the ameliorated growing conditions. We found that within most functional groups, species were highly individualistic with respect to the global change simulation, particularly within the forbs, whereas within the shrubs, responses were neutral to negative and widely variable in magnitude. In the heath community the response of the graminoid functional group was driven almost entirely by the grass Calamagrostis lapponica, which increased in abundance by an order of magnitude in the combined temperature and nutrient treatment. Furthermore, community context was important for species' responses to the simulations. Abundance of the pan-arctic species Carex bigelowii and Vaccinium vitis-idaea responded primarily to the temperature treatment in the meadow community whereas the nutrient treatment had stronger effects in the heath community. Over six growing seasons, more new species appeared in the experimental plots than in control plots in the meadow community, whereas in the heath community only one new species appeared. Our results from two closely situated but different plant communities show that functional groups do not predict individual species responses to simulated global change, and that these responses depend to a large extent on pre-existing physical conditions as well as biotic interactions such as competition and facilitation. It may be difficult to apply general trends of global change responses to specific local communities.
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| 6. |
- Virtanen, Marianna, et al.
(författare)
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Work disability before and after a major cardiovascular event : a ten-year study using nationwide medical and insurance registers
- 2017
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- We examined the trajectories of work disability before and after IHD and stroke events. New IHD (n = 13521) and stroke (n = 7162) cases in 2006-2008 were retrieved from nationwide Swedish hospital records and their annual work disability days five years before and after the date of diagnosis were retrieved from a nationwide disability register. There was no pre-event differences in disability days between the IHD and stroke cases and five years prior to the event, they were close to those observed in the general population. In the first post-event year, the adjusted mean days increased to 83.9 (95% CI 80.6-86.5) in IHD; to 179.5 (95% CI 172.4-186.8) in stroke, a six-fold increase in IHD and 14-fold in stroke. Work disability leveled off among the IHD cases but not among those who had stroke. The highest disability levels for the fifth post-event year after a stroke event was associated with pre-existing diabetes (146.9), mental disorder (141.2), non-employment (137.0), and immigrant status (117.9). In a working-age population, the increase in work disability after a cardiovascular event decreases close to the pre-event level in IHD but remains particularly high after stroke; among patients with comorbid depression or diabetes, immigrants, and those not in employment.
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