Fritz Hellmann
VU University Amsterdam
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Featured researches published by Fritz Hellmann.
Journal of Environmental Management | 2010
Fritz Hellmann; Peter H. Verburg
This paper presents an assessment of the potential impact of the EUs biofuel directive on European land use and biodiversity. In a spatially explicit analysis, it is determined which ecologically valuable land use types are likely to be directly replaced by biofuel crops. In addition, it is determined which land use types may be indirectly replaced by biofuel crops through competition over land between biofuel and food crops. Four scenarios of land use change are analyzed for the period 2000-2030 while for each scenario two policy variants are analyzed respectively with and without implementation of the biofuel directive. The results indicate that the area of semi natural vegetation, forest and High Nature Value farmland directly replaced by biofuel crops is small in all scenarios and differs little between policy variants. The direct effects of the directive on European land use and biodiversity therefore are relatively minor. The indirect effects of the directive on European land use and biodiversity are much larger than its direct effects. The area semi natural vegetation is found to be 3-8% smaller in policy variants with the directive as compared to policy variants without the directive. In contrast, little difference is found between the policy variants with respect to the forest area. The results of this study show that the expected indirect effects of the directive on biodiversity are much greater than its direct effects. This suggests that indirect effects need to be taken explicitly into account in assessing the environmental effects of biofuel crop cultivation and designing sustainable pathways for implementing biofuel policies.
Ecology and Society | 2012
Jan E. Vermaat; Steven Broekx; B. Van Eck; Guy Engelen; Fritz Hellmann; J.L. De Kok; H. Van der Kwast; Joachim Maes; Wim Salomons; W. Van Deursen
Using the systems approach framework (SAF), a coupled model suite was developed for simulating land-use decision making in response to nutrient abatement costs and water and nutrient fluxes in the hydrological network of the Scheldt River, and nutrient fluxes in the estuary and adjacent coastal sea. The purpose was to assess the efficiency of different long- term water quality improvement measures in current and future climate and societal settings, targeting nitrogen (N) load reduction. The spatial-dynamic model suite consists of two dynamically linked modules: PCRaster is used for the drainage network and is combined with ExtendSim modules for farming decision making and estuarine N dispersal. Model predictions of annual mean flow and total N concentrations compared well with data available for river and estuary (r² ≥ 0.83). Source apportionment was carried out to societal sectors and administrative regions; both households and agriculture are the major sources of N, with the regions of Flanders and Wallonia contributing most. Load reductions by different measures implemented in the model were comparable (~75% remaining after 30 yr), but costs differed greatly. Increasing domestic sewage connectivity was more effective, at comparatively low cost (47% remaining). The two climate scenarios did not lead to major differences in load compared with the business-as-usual scenario (~88% remaining). Thus, this spatially explicit model of water flow and N fluxes in the Scheldt catchment can be used to compare different long-term policy options for N load reduction to river, estuary, and receiving sea in terms of their effectiveness, cost, and optimal location of implementation.
The Handbook of Environmental Chemistry | 2014
Jan E. Vermaat; Sabine E. Apitz; Winfried E. H. Blum; Bob Harris; Fritz Hellmann; Wim Salomons; Tijs van Maasakkers
Downscaled articulations of Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES) have been outlined qualitatively for a hypothetical Southern, Central and Northern European river basin and a time horizon set at 2030. The purpose was to survey the sensitivity of ecosystem state indicators, to assess which drivers would be within the grasp of river basin management and to make a geographic comparison. Expert workshop debates were structured using a sequence of entries on drivers and the wider geographic setting, on the river basin and its hydrology, on pressures and on a range of ecosystem state indicators. The workshop elaborated IPCC-SRES scenarios A1 (global economy) and B2 (regional communities) only, since these are generally considered to be the two most divergent scenarios. Contrasts between these two scenarios in land, resource and energy use as well as in the orientation towards sustainability in governance were thought to lead to distinct contrasts in water and sediment delivery to stream networks, in contaminant loads and their remobilisation and in opportunities for riparian biota to populate available habitat. Also, these contrasts between A1 and B2 are probably most profound in the North and South. In contrast to other scenario assessments in the literature, the workshop found it highly plausible that agricultural land use would expand in the North, notably on deeper soils that had been afforested in previous decades. For the South, uncertainty on the direction of land use change was profound, leading to quite different, sketchy but plausible trajectories. Workshop participants remained cautious in the use of scenarios, because it was felt that adoption of altered lifestyles, transition to a carbon-neutral energy system or a nutrient-balanced, low-external-input agriculture can be charted as scenario elements, but their wholesale assimilation in real societies over the coming decades remains hard to predict. Notably discharge variability was foreseen to be highly responsive to the different scenarios but is considered to be under the influence of a river manager. Major drivers, such as the Common Agricultural Policy of the European Union and world market demand development for dairy or biofuel, will strongly affect land use and soil management. These appear to be largely outside the span of control of river basin authorities. The workshop hoped that risk preparedness in river management would include an identification of such major drivers outside their formal control and of the relevant institutions, both in different sectors and at different levels.
revue internationale de géomatique | 2008
Koen P. Overmars; Peter H. Verburg; Martha M. Bakker; Igor Staritsky; Fritz Hellmann
The objective of this paper is to translate land use changes (EU 25) into landscape changes. In contrast to land use maps the proposed landscape maps take the neighbourhood of a location into account additionally to solely the land use in a particular cell. Land use categories are reclassified into three main land use types and the dominant land use in a circle around the location is calculated. In addition, land use structure in the surroundings of a location is taken into account by calculating Shannon?s diversity index and reclassifying this into two categories. By combining these two dataset six landscape types are identified. By comparing the landscape maps for 2000 and 2030 we constructed a landscape change map. The results show a great spatial variety in landscape change within Europe. The relation between land use change and landscape change is non-linear depending on the nature and structure of the initial landscape and land use changes.
Biomass & Bioenergy | 2011
Fritz Hellmann; Peter H. Verburg
Biomass & Bioenergy | 2011
Martin Banse; Hans van Meijl; Andrzej Tabeau; G.B. Woltjer; Fritz Hellmann; Peter H. Verburg
Journal of Structural Biology | 2008
A.G. Balkema; Martha M. Bakker; Martin Banse; E. den Boer; L.A. Bouwman; B. Eickhout; B. Elbersen; I.R. Geijzendorffer; H. Heiligenberg; Fritz Hellmann; S.B. Hoek; H. van Meijl; K. Neumann; Koen P. Overmars; A.H. Prins; W.A. Rienks; C.J.E. Schulp; I.G. Staritsky; A.A. Tabeau; G.L. Velthof; Peter H. Verburg; L.A.E. Vullings; H. Westhoek; I. Woltjer
Biogeochemistry | 2010
Jan E. Vermaat; Fritz Hellmann
Ecological Modelling | 2012
Fritz Hellmann; Jan E. Vermaat
Australian Systematic Botany | 2008
A.G. Balkema; Martin Banse; B. Eickhout; I.R. Geijzendorffer; H. Heiligenberg; Fritz Hellmann; S.B. Hoek; H. van Meijl; K. Neumann; A.H. Prins; W.A. Rienks; Peter H. Verburg; L.A.E. Vullings; H. Westhoek; I. Woltjer