Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Modeling European ruminant production systems : Facing the challenges of climate change
Kipling, Richard P. ; Bannink, André ; Bellocchi, Gianni ; Dalgaard, Tommy ; Fox, Naomi J. ; Hutchings, Nicholas J. ; Kjeldsen, Chris ; Lacetera, Nicola ; Sinabell, Franz ; Topp, Cairistiona F.E. ; Oijen, Marcel van; Virkajärvi, Perttu ; Scollan, Nigel D. - \ 2016
Agricultural Systems 147 (2016). - ISSN 0308-521X - p. 24 - 37.
Food security - Livestock systems - Modeling - Pastoral systems - Policy support - Ruminants

Ruminant production systems are important producers of food, support rural communities and culture, and help to maintain a range of ecosystem services including the sequestering of carbon in grassland soils. However, these systems also contribute significantly to climate change through greenhouse gas (GHG) emissions, while intensification of production has driven biodiversity and nutrient loss, and soil degradation. Modeling can offer insights into the complexity underlying the relationships between climate change, management and policy choices, food production, and the maintenance of ecosystem services. This paper 1) provides an overview of how ruminant systems modeling supports the efforts of stakeholders and policymakers to predict, mitigate and adapt to climate change and 2) provides ideas for enhancing modeling to fulfil this role. Many grassland models can predict plant growth, yield and GHG emissions from mono-specific swards, but modeling multi-species swards, grassland quality and the impact of management changes requires further development. Current livestock models provide a good basis for predicting animal production; linking these with models of animal health and disease is a priority. Farm-scale modeling provides tools for policymakers to predict the emissions of GHG and other pollutants from livestock farms, and to support the management decisions of farmers from environmental and economic standpoints. Other models focus on how policy and associated management changes affect a range of economic and environmental variables at regional, national and European scales. Models at larger scales generally utilise more empirical approaches than those applied at animal, field and farm-scales and include assumptions which may not be valid under climate change conditions. It is therefore important to continue to develop more realistic representations of processes in regional and global models, using the understanding gained from finer-scale modeling. An iterative process of model development, in which lessons learnt from mechanistic models are applied to develop 'smart' empirical modeling, may overcome the trade-off between complexity and usability. Developing the modeling capacity to tackle the complex challenges related to climate change, is reliant on closer links between modelers and experimental researchers, and also requires knowledge-sharing and increasing technical compatibility across modeling disciplines. Stakeholder engagement throughout the process of model development and application is vital for the creation of relevant models, and important in reducing problems related to the interpretation of modeling outcomes. Enabling modeling to meet the demands of policymakers and other stakeholders under climate change will require collaboration within adequately-resourced, long-term inter-disciplinary research networks.

Monitoring vooroever Schelphoek Building for Nature proefvlak 2014 - 2017: voortgangsrapportage ontwerp vooroeverbestorting en T0-meting (T2014) epifauna en infauna
Tangelder, M. ; Ysebaert, T. ; Oijen, T. van; Kluijver, M. de - \ 2015
Yerseke : IMARES (Rapport / IMARES Wageningen UR C112/15) - 38
oeverbescherming van rivieren - oevers - fauna - benthos - oeverecosystemen - monitoring - natuurtechniek - zeeuwse eilanden - oosterschelde - riverbank protection - shores - riparian ecosystems - ecological engineering - eastern scheldt
Rijkswaterstaat voert vooroeverbestortingen uit op het deel van de dijk dat onder water ligt in de Ooster- en Westerschelde. Dit is nodig om de stabiliteit van de dijk en daarmee de waterveiligheid te kunnen blijven garanderen. Eerst werd hierbij alleen op veiligheidsdoelen gelet. Nieuw inzicht is echter dat je door gebruik van bepaalde materialen ook de natuur kunt faciliteren, dit principe wordt ‘Building for Nature’ genoemd. In 2014 is bij de oostelijke strekdam van locatie Schelphoek in de Oosterschelde een bestorting van zeegrind uitgevoerd. Doel van dit onderzoek is om de rekolonisatie en ontwikkeling van hard substraat soorten (epifauna) en soorten die leven in het sediment (infauna) op de nieuwe bestorting van breuksteen, zandsteen en zeegrind bij de locatie Schelphoek gedurende drie jaar na bestorting te volgen (2015-2017) en te vergelijken met de situatie voor bestorten (T0-situatie in 2014). Voorliggend rapport betreft een tussenrapportage met (1) een beschrijving van het ontwerp van de vooroeverbestorting en (2) een beschrijving van de T0-situatie in 2014 vóór het aanleggen van de vooroeverbestorting.
Coffee and tea consumption, genotype-based CYP1A2 and NAT2 activity and colorectal cancer risk—Results from the EPIC cohort study
Dik, V.K. ; Bueno-de-Mesquita, H.B. ; Oijen, M.G.C.T. van; Siersema, P.D. ; Uiterwaal, C.S.P.M. ; Gils, C.H. van; Duijnhoven, F.J.B. van - \ 2014
International Journal of Cancer 135 (2014)2. - ISSN 0020-7136 - p. 401 - 412.
colonic aberrant crypts - green tea - components kahweol - black tea - caffeine - cafestol - polyphenols - health - cells - rat
Coffee and tea contain numerous antimutagenic and antioxidant components and high levels of caffeine that may protect against colorectal cancer (CRC). We investigated the association between coffee and tea consumption and CRC risk and studied potential effect modification by CYP1A2 and NAT2 genotypes, enzymes involved in the metabolization of caffeine. Data from 477,071 participants (70.2% female) of the European Investigation into Cancer and Nutrition (EPIC) cohort study were analyzed. At baseline (1992–2000) habitual (total, caffeinated and decaffeinated) coffee and tea consumption was assessed with dietary questionnaires. Cox proportional hazards models were used to estimate adjusted hazard ratio's (HR) and 95% confidence intervals (95% CI). Potential effect modification by genotype-based CYP1A2 and NAT2 activity was studied in a nested case–control set of 1,252 cases and 2,175 controls. After a median follow-up of 11.6 years, 4,234 participants developed CRC (mean age 64.7¿±¿8.3 years). Total coffee consumption (high vs. non/low) was not associated with CRC risk (HR 1.06, 95% CI 0.95–1.18) or subsite cancers, and no significant associations were found for caffeinated (HR 1.10, 95% CI 0.97–1.26) and decaffeinated coffee (HR 0.96, 95% CI 0.84–1.11) and tea (HR 0.97, 95% CI 0.86–1.09). High coffee and tea consuming subjects with slow CYP1A2 or NAT2 activity had a similar CRC risk compared to non/low coffee and tea consuming subjects with a fast CYP1A2 or NAT2 activity, which suggests that caffeine metabolism does not affect the link between coffee and tea consumption and CRC risk. This study shows that coffee and tea consumption is not likely to be associated with overall CRC.
Next Generation Inactivated Polio Vaccine Manufacturing to Support Post Polio-Eradication Biosafety Goals
Thomassen, Y.E. ; Oever, A.G. van 't; Oijen, M.G.C.T. van; Wijffels, R.H. ; Pol, L.A. van der; Bakker, W.A.M. - \ 2013
PLoS One 8 (2013)12. - ISSN 1932-6203
sabin strains - technology-transfer - antigen - ipv - immunogenicity - culture - growth - safety - trial - cells
Worldwide efforts to eradicate polio caused a tipping point in polio vaccination strategies. A switch from the oral polio vaccine, which can cause circulating and virulent vaccine derived polioviruses, to inactivated polio vaccines (IPV) is scheduled. Moreover, a manufacturing process, using attenuated virus strains instead of wild-type polioviruses, is demanded to enhance worldwide production of IPV, especially in low- and middle income countries. Therefore, development of an IPV from attenuated (Sabin) poliovirus strains (sIPV) was pursued. Starting from the current IPV production process based on wild type Salk strains, adaptations, such as lower virus cultivation temperature, were implemented. sIPV was produced at industrial scale followed by formulation of both plain and aluminium adjuvanted sIPV. The final products met the quality criteria, were immunogenic in rats, showed no toxicity in rabbits and could be released for testing in the clinic. Concluding, sIPV was developed to manufacturing scale. The technology can be transferred worldwide to support post polio-eradication biosafety goals.
The Fish Fauna of Lake Victoria during a Centruy of Human Induced Perturbations
Witte, F. ; Kish-Machumu, M.A. ; Mkumbo, O.C. ; Wanink, J.H. ; Goudswaard, P.C. ; Rijssel, J.C. van; Oijen, M.J.P. van - \ 2013
In: Proceedings of the Fourth International Conference on African Fish and Fisheries / Snoeks, J., Getahun, A., Tervuren : Royal Museum for Central Africa (Zoological Documentation Online Series ) - ISBN 9789491615146 - p. 49 - 66.
De vererving van het witrikpatroon en de variatie daaarin
Schoon, M. ; Oldenbroek, J.K. ; Oijen, M. van - \ 2013
Zeldzaam huisdier 38 (2013)3. - ISSN 0929-905X - p. 18 - 19.
witrik - rundveerassen - zeldzame rassen - diergenetica - dierveredeling - kleur - overerving - coloursides white back - cattle breeds - rare breeds - animal genetics - animal breeding - colour - inheritance
In een afstudeeropdracht voor van Hall Larenstein is de vererving van de witrikkleur bij runderen bestudeerd en is de vraag beantwoord waarom er zoveel kleurpatronen zijn binnen deze kleurslag.
Environmental change impacts on the C- and N-cycle of European forests: a model comparison study
Cameron, D.R. ; Oijen, M. Van; Werner, C. ; Butterbach-Bahl, K. ; Grote, R. ; Haas, E. ; Heuvelink, G.B.M. ; Kiese, R. ; Kros, J. ; Kuhnert, M. ; Leip, A. ; Reinds, G.J. ; Reuter, H.I. ; Schelhaas, M.J. ; Vries, W. de; Yeluripati, J. - \ 2013
Biogeosciences 10 (2013). - ISSN 1726-4170 - p. 1751 - 1773.
nitrogen limitation - temperate forests - carbon budget - soils - n2o - ecosystems - agriculture - emissions - growth - decomposition
Forests are important components of the greenhouse gas balance of Europe. There is considerable uncertainty about how predicted changes to climate and nitrogen deposition will perturb the carbon and nitrogen cycles of European forests and thereby alter forest growth, carbon sequestration and N2O emission. The present study aimed to quantify the carbon and nitrogen balance, including the exchange of greenhouse gases, of European forests over the period 2010–2030, with a particular emphasis on the spatial variability of change. The analysis was carried out for two tree species: European beech and Scots pine. For this purpose, four different dynamic models were used: BASFOR, DailyDayCent, INTEGRATOR and Landscape-DNDC. These models span a range from semi-empirical to complex mechanistic. Comparison of these models allowed assessment of the extent to which model predictions depended on differences in model inputs and structure. We found a European average carbon sink of 0.160 ± 0.020 kgC m-2 yr-1 (pine) and 0.138 ± 0.062 kgC m-2 yr-1 (beech) and N2O source of 0.285 ± 0.125 kgN ha-1 yr-1 (pine) and 0.575 ± 0.105 kgN ha-1 yr-1 (beech). The European average greenhouse gas potential of the carbon sink was 18 (pine) and 8 (beech) times that of the N2O source. Carbon sequestration was larger in the trees than in the soil. Carbon sequestration and forest growth were largest in central Europe and lowest in northern Sweden and Finland, N. Poland and S. Spain. No single driver was found to dominate change across Europe. Forests were found to be most sensitive to change in environmental drivers where the drivers were limiting growth, where changes were particularly large or where changes acted in concert. The models disagreed as to which environmental changes were most significant for the geographical variation in forest growth and as to which tree species showed the largest rate of carbon sequestration. Pine and beech forests were found to have differing sensitivities to environmental change, in particular the response to changes in nitrogen and precipitation, with beech forest more vulnerable to drought. There was considerable uncertainty about the geographical location of N2O emissions. Two of the models BASFOR and LandscapeDNDC had largest emissions in central Europe where nitrogen deposition and soil nitrogen were largest, whereas the two other models identified different regions with large N2O emission. N2O emissions were found to be larger from beech than pine forests and were found to be particularly sensitive to forest growth.
Accomodating Two Worlds in One Organization: Changing Board Models in Agricultural Cooperatives
Bijman, J. ; Hendrikse, G.W.J. ; Oijen, A. - \ 2013
Managerial and Decision Economics 34 (2013)3-5. - ISSN 0143-6570 - p. 204 - 217.
While most economic organisation literature on cooperatives has focused on changes in income rights, we study changes in the allocation of decision rights between board of directors (representing members) and managers. The traditional role of the board is to direct the activities of the managers. However, professional management increasingly makes most strategic decisions, pushing the board into a supervisory role. We present two groups of findings on changing board–management relationships. We identify three corporate governance models: traditional, management and corporation. And we present an empirical illustration showing a relationship between the choice of board model, and product portfolio and performance.
The Wadden Sea Region: Towards a science for sustainable development
Kabat, P. ; Bazelmans, J. ; Dijk, J. van; Hermans, P. ; Oijen, T. van - \ 2012
Ocean & Coastal Management 68 (2012). - ISSN 0964-5691 - p. 4 - 17.
social-ecological systems - southern north-sea - tidal basin - level rise - ems estuary - netherlands - ecosystem - climate - management - transformations
The Wadden Sea is one of the largest intertidal areas in the world and has been designated as a UNESCO World Heritage Site in recognition of its unique natural features. Major changes in the morphology and ecology of the Wadden Sea over the past millennium resulted from increasing anthropogenic influences such as coastal protection, land claim from the sea and drainage of wetland for agriculture, exploitation of natural resources from hunting and fishing to the extraction of groundwater, gas and oil, industrialisation at port locations and tourism at the islands. A sustainable future can only be achieved if policy and management are backed by solid science. Many of the anticipated changes result from the upscaling of pressures on the Wadden Sea system. Economic globalization leads to upscaling of fisheries, tourism and industrial activities, and thus to changed pressures on space and nature. Climate change will lead to changes in hydrographic patterns, species distribution and possibly tourism; through sea-level rise it will put pressure on coastal protection and the extent of intertidal areas. Invasions of exotic species will transform the ecosystem. There are three major related challenges to management: 1. Nature conservation in a changing system requires a focus on preservation of the values and not the state of the system; 2. The adaptation of the management structure to the scale increase of the pressures, so that local and regional management becomes better nested in transregional and transnational governance structures; 3. Finally, the management approach needs to deal with increasing uncertainty in external forcing of the system, as well as with nonlinearities in system dynamics when it is pushed outside its normal range of operation. Based on these pressures and management challenges, we advocate an integrated social-ecological systems approach for the scientific study and the science-based management of the Wadden Sea Region. The essential characteristics of this approach are strong interdisciplinarity and a focus on aspects of scale and cumulative processes.
Environmental change impacts on the C- and N-cycle of European forests: a model comparison study
Cameron, D. ; Oijen, M. van; Werner, C. ; Butterbach-Bahl, K. ; Haas, E. ; Heuvelink, G.B.M. ; Grote, R. ; Kiese, R. ; Kuhnert, M. ; Kros, J. ; Leip, A. ; Reuter, H.I. ; Reinds, G.J. ; Schelhaas, M.J. ; Vries, W. de; Yeluripati, J. - \ 2012
Biogeosciences Discussions 9 (2012). - ISSN 1810-6277 - p. 11041 - 11101.
Forests are important components of the greenhouse gas balance of Europe. There is considerable uncertainty about how predicted changes to climate and nitrogen deposition will perturb the carbon and nitrogen cycles of European forests and thereby alter forest growth, carbon sequestration and N2O emission. The present study aimed to quantify the carbon and nitrogen balance, including the exchange of greenhouse gases, of European forests over the period 2010–2030, with a particular emphasis on the spatial variability of change. The analysis was carried out for two tree species: European beech and Scots pine. For this purpose, four different dynamic models were used: BASFOR, DailyDayCent, INTEGRATOR and Landscape-DNDC. These models span a range from semi-empirical to complex mechanistic. Comparison of these models allowed assessment of the extent to which model predictions depended on differences in model inputs and structure. We found a European average carbon sink of 0.160 ± 0.020 kgC m-2 yr-1 (pine) and 0.138 ± 0.062 kgC m-2 yr-1 (beech) and N2O source of 0.285 ± 0.125 kgN ha-1 yr-1 (pine) and 0.575 ± 0.105 kgN ha-1 yr-1 (beech). The European average greenhouse gas potential of the carbon source was 18 (pine) and 8 (beech) times that of the N2O source. Carbon sequestration was larger in the trees than in the soil. Carbon sequestration and forest growth were largest in central Europe and lowest in northern Sweden and Finland, N. Poland and S. Spain. No single driver was found to dominate change across Europe. Forests were found to be most sensitive to change in environmental drivers where the drivers were limiting growth, where changes were particularly large or where changes acted in concert. The models disagreed as to which environmental changes were most significant for the geographical variation in forest growth and as to which tree species showed the largest rate of carbon sequestration. Pine and beech forests were found to have differing sensitivities to environmental change, in particular the response to changes in nitrogen and precipitation, with beech forest more vulnerable to drought. There was considerable uncertainty about the geographical location of N2O emissions. Two of the models BASFOR and LandscapeDNDC had largest emissions in central Europe where nitrogen deposition and soil nitrogen were largest whereas the two other models identified different regions with large N2O emission. N2O emissions were found to be larger from beech than pine forests and were found to be particularly sensitive to forest growth.
Carbon and nitrogen fluxes in European forests in response to changes in nitrogen deposition, climate and CO2 between 2005 end 2030: a model comparison study
Cameron, D. ; Oijen, M. van; Butterbach-Bahl, K. ; Heuvelink, G.B.M. ; Kros, J. ; Reinds, G.J. ; Schelhaas, M.J. ; Vries, W. de - \ 2011
Social safeguards in the Ghana-EU Voluntary Partnership Agreement (VPA); Triggering improved forest governance or an afterthought?
Arts, B.J.M. ; Wiersum, K.F. ; Aggrey, J. ; Owusu, B. ; Oijen, D.C.C. van; Nketiah, S. ; Wit, M. ; Zagt, R. ; Vellema, H. ; Rozemeijer, N. - \ 2010
Wageningen : Wageningen Universiteit and Research Centre - ISBN 9789085859703 - 12
bosbedrijfsvoering - houtkap - houthandel - middelen van bestaan - sociaal beleid - rechtshandhaving - ghana - forest management - logging - timber trade - livelihoods - social policy - law enforcement
Models for supporting forest management in a changing environment
Fontes, L. ; Bontemps, J.D. ; Bugmann, H. ; Oijen, M. van; Gracia, C. ; Kramer, K. ; Lindner, M. ; Rötzer, T. ; Skovsgaard, J.P. - \ 2010
Forest Systems 19 (2010). - ISSN 2171-5068 - p. 8 - 29.
fagus-sylvatica l. - of-the-art - general quantitative theory - central-european forests - state-space approach - growth-model - tree growth - ecosystem management - climate-change - site index
Forests are experiencing an environment that changes much faster than during the past several hundred years. In addition, the abiotic factors determining forest dynamics vary depending on its location. Forest modeling thus faces the new challenge of supporting forest management in the context of environmental change. This review focuses on three types of models that are used in forest management: empirical (EM), process-based (PBM) and hybrid models. Recent approaches may lead to the applicability of empirical models under changing environmental conditions, such as (i) the dynamic state-space approach, or (ii) the development of productivity-environment relationships. Twenty-five process-based models in use in Europe were analyzed in terms of their structure, inputs and outputs having in mind a forest management perspective. Two paths for hybrid modeling were distinguished: (i) coupling of EMs and PBMs by developing signal-transfer environment-productivity functions; (ii) hybrid models with causal structure including both empirical and mechanistic components. Several gaps of knowledge were identified for the three types of models reviewed. The strengths and weaknesses of the three model types differ and all are likely to remain in use. There is a trade-off between how little data the models need for calibration and simulation purposes, and the variety of input-output relationships that they can quantify. PBMs are the most versatile, with a wide range of environmental conditions and output variables they can account for. However, PBMs require more data making them less applicable whenever data for calibration are scarce. EMs, on the other hand, are easier to run as they require much less prior information, but the aggregated representation of environmental effects makes them less reliable in the context of environmental changes. The different disadvantages of PBMs and EMs suggest that hybrid models may be a good compromise, but a more extensive testing of these models in practice is required.
Implementing FLEGT: Impacts on local people
Wiersum, K.F. ; Oijen, D.C.C. van - \ 2010
Wageningen, the Netherlands : Wageningen University and Research Centre - ISBN 9789085858966 - 19
houtkap - houthandel - illegale kap - participatie - middelen van bestaan - logging - timber trade - illicit felling - participation - livelihoods
The impact of nitrogen deposition on carbon sequestration by European forests and heathlands
Vries, W. de; Solberg, S. ; Dobbertin, M. ; Sterba, H. ; Laubhann, D. ; Oijen, M. van; Evans, C. ; Gundersen, P. ; Kros, H. ; Wamelink, W. ; Reinds, G.J. ; Sutton, M.A. - \ 2009
Forest Ecology and Management 258 (2009)8. - ISSN 0378-1127 - p. 1814 - 1823.
atmospheric nitrogen - temperate forest - terrestrial ecosystems - harvard forest - mineral soil - n deposition - saturation - additions - growth - fertilization
In this study, we present estimated ranges in carbon (C) sequestration per kg nitrogen (N) addition in above-ground biomass and in soil organic matter for forests and heathlands, based on: (i) empirical relations between spatial patterns of carbon uptake and influencing environmental factors including nitrogen deposition (forests only), (ii) 15N field experiments, (iii) long-term low-dose N fertilizer experiments and (iv) results from ecosystem models. The results of the various studies are in close agreement and show that above-ground accumulation of carbon in forests is generally within the range 15–40 kg C/kg N. For heathlands, a range of 5–15 kg C/kg N has been observed based on low-dose N fertilizer experiments. The uncertainty in C sequestration per kg N addition in soils is larger than for above-ground biomass and varies on average between 5 and 35 kg C/kg N for both forests and heathlands. All together these data indicate a total carbon sequestration range of 5–75 kg C/kg N deposition for forest and heathlands, with a most common range of 20–40 kg C/kg N. Results cannot be extrapolated to systems with very high N inputs, nor to other ecosystems, such as peatlands, where the impact of N is much more variable, and may range from C sequestration to C losses
Processing Cooperatives and Diversification
Hendrikse, G.W.J. ; Feng, A.A.C. ; Oijen, R. van; Smit, R. ; Bijman, J. - \ 2009
In: Beiträge der genossenschaftlichen Selbsthilfe zur wirtschaftlichen und sozialen Entwicklung Berlin : Lit Verlag - ISBN 9783643103987 - p. 271 - 289.
Fish Fauna of the Nile
Witte, F. ; Oijen, M.J.P. van; Sibbing, F.A. - \ 2009
In: The Nile. Origin, Environments, Limnology and Human Use / Dumont, H.J., Springer Science + Business Media B.V. (Monographiae Biologicae 89) - ISBN 9781402097256 - p. 647 - 676.
Modelling impacts of changes in carbon dioxide concentration, climate and nitrogen deposition on carbon sequestration by European forests and forest soils
Wamelink, G.W.W. ; Wieggers, H.J.J. ; Reinds, G.J. ; Kros, J. ; Mol-Dijkstra, J.P. ; Oijen, M. van; Vries, W. de - \ 2009
Forest Ecology and Management 258 (2009)8. - ISSN 0378-1127 - p. 1794 - 1805.
elevated atmospheric co2 - plant-growth - productivity - ecosystems - temperate - responses - canopy - face - metaanalysis - predictions
Changes in the Earth's atmosphere are expected to influence the growth, and therefore, carbon accumulation of European forests. We identify three major changes: (1) a rise in carbon dioxide concentration, (2) climate change, resulting in higher temperatures and changes in precipitation and (3) a decrease in nitrogen deposition. We adjusted and applied the hydrological model Watbal, the soil model SMART2 and the vegetation model SUMO2 to asses the effect of expected changes in the period 1990 up to 2070 on the carbon accumulation in trees and soils of 166 European forest plots. The models were parameterized using measured soil and vegetation parameters and site-specific changes in temperature, precipitation and nitrogen deposition. The carbon dioxide concentration was assumed to rise uniformly across Europe. The results were compared to a reference scenario consisting of a constant CO2 concentration and deposition scenario. The temperature and precipitation scenario was a repetition of the period between 1960 and 1990. All scenarios were compared to the reference scenario for biomass growth and carbon sequestration for both the soil and the trees. The predicted effects of changes in climate, CO2 concentration and nitrogen deposition on carbon sequestration by trees depend largely on tree species and location (latitude). The assumed decrease in nitrogen deposition causes a decrease of carbon accumulation all over Europe and for all modelled tree species. A rise in carbon dioxide concentration gives a rise in carbon accumulation all over Europe. Climate change gives a mixed result, with a decrease in carbon accumulation in the South of Europe and an increase in the North. When the scenarios are combined, an increase in biomass accumulation is predicted at most of the sites, with a rise in growth rate mostly between 0 and 100%. The predicted effects of a change in climate, CO2 concentration and nitrogen deposition on soil carbon sequestration is generally lower than the effect on carbon sequestration by the trees. However, the magnitude is similar as is the location effect (latitude). A net carbon release was predicted at several sites in the south due to the effect of climate change. Overall, we conclude that where nitrogen deposition was a major driver for a change in forest growth in the past, it is climate change, and to a lesser extent CO2 change, that will influence forest growth in the future.
Effects of climate change, CO2 fertilization and nitrogen deposition on growth and carbon sequestration of forest ecosystems in Europe
Vries, W. de; Kros, J. ; Wamelink, G.W.W. ; Reinds, G.J. ; Solberg, S. ; Dobbertin, M. ; Sterba, H. ; Laubhann, D. ; Oijen, M. van; Sutton, M.A. - \ 2008
In: Cost Strategic Workshop "Forest ecosystems in a changing environment: identifying future monitoring and research needs”, Istanbul, Turkey, 11 - 13 March, 2008. - Istanbul, Turkey : - p. 30 - 31.
Bayesian calibration of the VSD soil acidification model using European forest monitoring data
Reinds, G.J. ; Oijen, M. van; Heuvelink, G.B.M. ; Kros, J. - \ 2008
Geoderma 146 (2008)3-4. - ISSN 0016-7061 - p. 475 - 488.
acid deposition - critical loads - atmospheric deposition - chemistry - ecosystems - reduction - water
Over the past years, Bayesian calibration methods have been successfully applied to calibrate ecosystem models. Bayesian methods combine prior probability distributions of model parameters, based on assumptions about their magnitude and uncertainty, with estimates of the likelihood of the simulation results by comparison with observed values. Bayesian methods also quantify the uncertainty in the updated posterior parameters, which can be used to perform an analysis of model output uncertainty. In this paper, we applied Bayesian techniques to calibrate the VSD soil acidification model using data from 182 intensively monitored forest sites in Europe. Out of these 182 plots, 122 plots were used to calibrate VSD and the remaining 60 plots to validate the calibrated model. Prior distributions for the model parameters were based on available literature. Since the available literature shows a strong dependence of some VSD parameters on, for example, soil texture, prior distributions were allowed to depend on soil group (i.e. soils with similar texture or C/N ratio). The likelihood was computed by comparing modelled soil solution concentrations with observed concentrations for the period 1996¿2001. Markov Chain Monte Carlo (MCMC) was used to sample the posterior parameter space. Two calibration approaches were applied. In the single-site calibration, the plots were calibrated separately to obtain plot-specific posterior distributions. In the multi-site approach priors were assumed constant in space for each soil group, and all plots were calibrated simultaneously yielding one posterior probability distribution for each soil group. Results from the single-site calibrations show that the model performed much better after calibration compared to a run with standard input parameters when validated on the 60 validation plots. Posterior distributions for H-Al equilibrium constants narrowed down, thus decreasing parameter uncertainty. For base cation weathering of coarse textured soils the posterior distribution shifted to larger values, indicating an initial underestimation of the weathering rate for these soils. Results for the parameters related to nitrogen modelling showed that the nitrogen processes model formulations in VSD may have to be reconsidered as the relationship between nitrogen immobilization and the C/N ratio of the soil, as assumed in VSD, was not substantiated by the validation. The multi-site calibration also strongly decreased model error for most model output parameters, but model error was somewhat larger than the median model error from the single-site calibration except for nitrate. Because the large number of plots calibrated at the same time provided very many observations, the Markov Chain converged to a very narrow parameter space, leaving little room for posterior parameter uncertainty. For an uncertainty analysis with VSD on the European scale, this study provides promising results, but more work is needed to investigate how the results can be used on a European scale by looking at regional patterns in calibrated parameters from the site calibration or by calibrating for regions instead of all of Europe.
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