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- Andersson, Magdalena, et al.
(författare)
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Effects of wetland liming on vegetation in south-west Sweden
- 2005
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Ingår i: Hunova I (Ed) Acid Rain 2005, 7th International Conference on Acid Deposition, Conference Abstracts.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Seven wetland areas treated with coarse grain (Ø = 0-3 mm) lime in 1998 and seven reference areas with the same vegetation type were invented for vascular plants and mosses in the summer of 2003. The inventory was made using twenty 0.5 * 0.5 m2 plots, evenly distributed along a transect. The vascular plants and mosses showed a high degree of similarity between treated and reference areas (Sørensen´s index = 0.83 and 0.75 for vascular plants and mosses, respectively). The difference in vegetation composition (weakly significant) between treated and reference according to χ2 test, was most probably not caused by liming. No signs of lime related injuries were observed on the vascular plants. However, Sphagnum mosses showed substantial (14% of all plots) visible injury in all lime treated areas, but no such injuries in any of the reference areas. This kind of injury on Sphagnum mosses was severe and the mosses were largely dead and in a state of decomposition. It is concluded from the present study that Sphagnum mosses are significantly and negatively affected by the kind of lime used. Vascular plants were unaffected, but five years may be an in sufficient duration of time for effects to become established. However, it seems most likely that mosses are much more sensitive to wetland liming than vascular plants.
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- Buker, P, et al.
(författare)
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Comparison of different stomatal conductance algorithms for ozone flux modelling
- 2005
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Ingår i: UNECE – Workshop “Critical Levels of Ozone: Further applying and developing the flux-based concept”, Obergurgl, 15-19 November 2005.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Two widely used algorithms for modelling stomatal conductance (gs) were compared in order to evaluate the approach leading to the most realistic predictions of stomatal fluxes to vegetated surfaces: a multiplicative algorithm initially developed by Jarvis (1976) and refined by Emberson et al. (2000) (DO3SE ) and a photosynthesis-based Ball&Berry-type algorithm developed by Nikolov et al. (1995) (LEAFC3). Both models were parameterised for several crop and tree species (wheat, grapevine, Scots pine, beech and birch) and have been applied to various datasets – with the main focus on wheat - representing different European regions (North, Central and South Europe). A sensitivity analysis has been carried out for both models to evaluate the dependence of gs on the meteorological parameters temperature, photosynthetic active radiation and vapour pressure deficit. Furthermore, in order to test whether a general species-specific parameterisation can account for differences in gs due to plants growing under different climatic conditions throughout Europe, the models have been re-parameterised for local meteorological conditions. A direct comparison of both models showed that the net photosynthetic-based model required more detailed meteorological (e.g. ambient CO2-concentration, dew-point temperature) and plant-physiological (e.g. Vcmax and Jmax) input parameters while not delivering a substantially higher R2 when comparing measured and modelled gs. The relative weakness of the multiplicative model lies in its dependence on the maximum stomatal conductance (gmax), whereas the photosynthesis-based model is not taking into account phenology-related changes in gs. Furthermore, the results show that an equally close relationship between gs and net photosynthetic rate throughout the entire growing season is questionable. We conclude that the multiplicative approach is favourable for calculating stomatal fluxes on a wider scale (e.g. within EMEP-deposition model), whereas the photosynthesis-based approach is a potential alternative for modelling fluxes on a local scale.
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- Karlsson, Per Erik, 1957, et al.
(författare)
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Economic assessment of the negative impacts of ozone on crop yields and forest production. A case study of the estate Ostads Sateri in southwestern Sweden
- 2005
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Ingår i: Ambio. - 0044-7447. ; 34:1, s. 32-40
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Tidskriftsartikel (refereegranskat)abstract
- Ground level ozone concentrations, in combination with the prevailing climate, at the estate Ostads Sateri in southwestern Sweden were estimated to reduce the yield of wheat and potato ranging between 5% and 10%. Occasionally, in years with the highest ozone concentrations and/or climatic conditions favoring high rates of ozone uptake to the leaves, yield loss levels above 10% may occur. Based on simple extrapolation, these ozone-induced reductions of crop yields at Ostads Sateri represent a potential total annual yield loss in Sweden in the range of 24.5 million Euro for wheat and 7.3 million Euro for potato, respectively. A simulation of forest growth at Ostad Sateri predicted that prevailing mean ozone exposure during 1993-2003 had the potential to reduce forest growth by 2.2% and the economic return of forest production by 2.6%. Using this value for extrapolation to the national level, the potential annual economic loss for Sweden due to negative impacts of ozone on forest production would be in the range of 56 million Euro (2004 prices).
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