| 1. |
- De Vries, W., et al.
(författare)
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Use of dynamic soil-vegetation models to assess impacts of nitrogen deposition on plant species composition: an overview
- 2010
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761. ; 20:1, s. 60-79
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Tidskriftsartikel (refereegranskat)abstract
- Field observations and experimental data of effects of nitrogen (N) deposition oil plant species diversity have been Used to derive empirical critical N loads for various ecosystems. The great advantage of such an approach is the inclusion of field evidence, but there are also restrictions, such as the absence of explicit criteria regarding significant effects on the vegetation, and the impossibility to predict future impacts when N deposition changes. Model approaches Call account for this. In this paper, we review the possibilities of static and dynamic multispecies models in combination with dynamic soil-vegetation models to (1) predict plant species composition as a function of atmospheric N deposition and (2) calculate critical N loads in relation to a prescribed protection level of the species composition. The similarities between the models are presented, but also several important differences, including the Use of different indicators for N and acidity and the prediction of individual plant species VS. Plant communities. A summary of the strengths and weaknesses of the various Models, including their validation status, is given. Furthermore,. examples are given of critical load calculations with the model chains and their comparison with empirical critical N loads. We show that linked biogeochemistry-biodiversity models for N have potential for applications to support European policy to reduce N input, but the definition of damage thresholds for terrestrial biodiversity represents a major challenge. There is also a clear need for further testing and validation of the models against long-term monitoring or long-term experimental data sets and against large-scale survey data. This requires a focused data collection ill Europe. combing vegetation descriptions with variables affecting the species diversity. such as Soil acidity, nutrient status and water availability. Finally there is a need for adaptation and upscaling of the models beyond the regions for which dose-response relationships have been parameterized, to make them generally applicable.
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| 2. |
- Etzold, Sophia, et al.
(författare)
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Nitrogen deposition is the most important environmental driver of growth of pure, even-aged and managed European forests
- 2020
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 458
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Tidskriftsartikel (refereegranskat)abstract
- Changing environmental conditions may substantially interact with site quality and forest stand characteristics, and impact forest growth and carbon sequestration. Understanding the impact of the various drivers of forest growth is therefore critical to predict how forest ecosystems can respond to climate change. We conducted a continental-scale analysis of recent (1995–2010) forest volume increment data (ΔVol, m3 ha−1 yr−1), obtained from ca. 100,000 coniferous and broadleaved trees in 442 even-aged, single-species stands across 23 European countries. We used multivariate statistical approaches, such as mixed effects models and structural equation modelling to investigate how European forest growth respond to changes in 11 predictors, including stand characteristics, climate conditions, air and site quality, as well as their interactions. We found that, despite the large environmental gradients encompassed by the forests examined, stand density and age were key drivers of forest growth. We further detected a positive, in some cases non-linear effect of N deposition, most pronounced for beech forests, with a tipping point at ca. 30 kg N ha−1 yr−1. With the exception of a consistent temperature signal on Norway spruce, climate-related predictors and ground-level ozone showed much less generalized relationships with ΔVol. Our results show that, together with the driving forces exerted by stand density and age, N deposition is at least as important as climate to modulate forest growth at continental scale in Europe, with a potential negative effect at sites with high N deposition.
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| 3. |
- de Vries, W., et al.
(författare)
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Modelling long-term impacts of changes in climate, nitrogen deposition and ozone exposure on carbon sequestration of European forest ecosystems
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 605, s. 1097-1116
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Tidskriftsartikel (refereegranskat)abstract
- We modelled the effects of past and expected future changes in climate (temperature, precipitation), CO2 concentration, nitrogen deposition (N) and ozone (O-3) exposure (phytotoxic ozone dose, POD) on carbon (C) sequestration by European forest ecosystems for the period 1900-2050. Tree C sequestration was assessed by using empirical response functions, while soil C sequestration was simulated with the process-based model VSD, combined with the RothC model. We evaluated two empirical growth responses to N deposition (linear and non-linear) and two O-3 exposure relationships (linear function with total biomass or net annual increment). We further investigated an 'interactive model' with interactions between drivers and a 'multiplicativemodel', in which the combined effect is the product of individual drivers. A single deposition and climate scenario was used for the period 1900-2050. Contrary to expectations, growth observations at European level for the period 1950-2010 compared better with predictions by the multiplicative model than with the interactive model. This coincides with the fact that carbon responses in kg C ha(-1) yr(-1) per unit change in drivers, i.e. per degrees C, ppm CO2, kg N ha(-1) yr(-1) and mmol m(-2) yr(-1) POD, aremore in line with literature data when using themultiplicativemodel. Compared to 1900, the estimated European average total C sequestration in both forests and forest soils between 1950 and 2000 increased by 21% in the interactive model and by 41% in the multiplicative model, but observed changes were even higher. This growth increase is expected to decline between 2000 and 2050. The simulated changes between 1950 and 2000 were mainly due to the increase in both N deposition and CO2, while the predicted increases between 2000 and 2050 were mainly caused by the increase in CO2 and temperature, and to lesser extent a decrease in POD, counteracted by reduced N deposition. (C) 2017 Elsevier B.V. All rights reserved.
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