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- Giesecke, Thomas, et al.
(författare)
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The effect of past changes in inter-annual temperature variability on tree distribution limits
- 2010
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Ingår i: Journal of Biogeography. - : Wiley. - 1365-2699 .- 0305-0270. ; 37:7, s. 1394-1405
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Tidskriftsartikel (refereegranskat)abstract
- Aim The northern limits of temperate broadleaved species in Fennoscanndia are controlled by their requirements for summer warmth for successful regeneration and growth as well as by the detrimental effects of winter cold on plant tissue. However, occurrences of meteorological conditions with detrimental effects on individual species are rare events rather than a reflection of average conditions. We explore the effect of changes in inter-annual temperature variability on the abundances of the tree species Tilia cordata, Quercus robur and Ulmus glabra near their distribution limits using a process-based model of ecosystem dynamics. Location A site in central Sweden and a site in southern Finland were used as examples for the ecotone between boreal and temperate forests in Fennoscandia. The Finnish site was selected because of the availability of varve-thickness data. Methods The dynamic vegetation model LPJ-GUESS was run with four scenarios of inter-annual temperature forcing for the last 10,000 years. In one scenario the variability in the thickness of summer and winter varves from the annually laminated lake in Finland was used as a proxy for past inter-annual temperature variability. Two scenarios were devised to explore systematically the effect of stepwise changes in the variance and shape parameter of a probability distribution. All variability scenarios were run both with and without the long-term trend in Holocene temperature change predicted by an atmospheric general circulation model. Results Directional changes in inter-annual temperature variability have significant effects on simulated tree distribution limits through time. Variations in inter-annual temperature variability alone are shown to alter vegetation composition by magnitudes similar to the magnitude of changes driven by variation in mean temperatures. Main conclusions The varve data indicate that inter-annual climate variability has changed in the past. The model results show that past changes in species abundance can be explained by changes in the inter-annual variability of climate parameters as well as by mean climate. Because inter-annual climatic variability is predicted to change in the future, this component of climate change should be taken into account both when making projections of future plant distributions and when interpreting vegetation history.
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| 2. |
- Löfgren, Kent, 1966-, et al.
(författare)
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Meeting the Challenges of Generational Change in the Teaching Profession : Towards a European Model for Intergenerational Teacher Collaboration
- 2013
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Ingår i: Educational Research eJournal. - : Educational Research e-Journal (EREJ). - 2254-0385. ; 2:2, s. 107-119
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Tidskriftsartikel (refereegranskat)abstract
- In a European-wide effort to improve the professional development of teachers, the 2AgePro project was conducted from November 2008 to October 2010. One of its goals was to develop and test different forms of intergenerational teacher collaboration among junior and senior teachers in primary and secondary schools. Another aim was to utilise the results from these pilots, which were conducted in the Czech Republic, Finland, Germany, the Netherlands, and Sweden, to create a model for intergenerational collaboration that could be used in any national or cultural setting. This article reports on the national pilots and proposes a European model for intergenerational collaboration for teachers.
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