graziano ceddia | University of Bern (original) (raw)

Books by graziano ceddia

Papers by graziano ceddia

Environmental Science & Policy, 2016

Flood events have become more frequent in Europe, and the adaptation to the increasing flood risk... more Flood events have become more frequent in Europe, and the adaptation to the increasing flood risks is needed. The Flood Directive set up a series of measures to increase European resilience, establishing Flood Risk Management Plans (FRMPs) at the level of the river basin district as one relevant action. In order to efficiently fulfil this objective, the involvement of stakeholders as well as the analysis of their roles, responsibilities, and demands has been considered to be crucial to develop FRMPs. As a result, the hypothesis tested in this paper is that a consensus solution for the 2021 update Austrian Flood Risk Management Plan is feasible. To demonstrate this, both in-depth interviews and questionnaires to key Austrian stakeholders are implemented. The information collected in both participatory techniques are then used to run a conflict prevention analysis. The results show that (a) improving the coordination among regions and including better land-use planning approaches are preferable to a hypothetical business as usual scenario; and (b) a consensus solution for the 2021 update Austrian FRMP might be achievable on the basis of both a deep discussion on the state-of-the art and green infrastructure development.

… Congress, August 30- …, Jan 1, 2011

Both governmental and non-governmental organizations are engaged in the promotion of soil and wat... more Both governmental and non-governmental organizations are engaged in the promotion of soil and water conservation practices in northern Ghana, but adoption is believed to be low. This study thus examines the determinants of conservation practices by farming households in the area. Data for the study was collected from 445 households located in 15 communities in northern Ghana. Univariate, bivariate and multivariate probit models were used to analyse the decision to adopt six conservation practices in the area. Results show the major determinants of adoption are plot and cropping characteristics such as location; and socio-economic and institutional variables such as number of contacts with extension officers, membership in farmer association and distance to major market. A major policy implication of the study is the strengthening of extension service in the area to significantly boost conservation adoption.

The paper analyses the management of an infectious disease in a sympatric metapopulation, under b... more The paper analyses the management of an infectious disease in a sympatric metapopulation, under both Nash and cooperative behaviour, through the development of a differential game and an optimal control problem with connected local state variables. As pathogens are renewable resources with negative value, the problem may be non-convex. Since the disease can be transmitted across various connected populations, externalities may be involved. A numerical application is presented, with reference to a livestock disease that can be transmitted between herds on common pastures. The results suggest that optimal eradication in finite time should be pursued when possible. However, optimal eradication is not always feasible (sometimes eradication can be only achieved asymptotically), and the ecology of the disease is of paramount importance in this respect. Also, convergence to an internal steady-state does not minimise the present value of the disease damage and control cost (a result consistent with the existing literature). Ignoring these results may lead to inadequate policy design.

The science and management of infectious disease are entering a new stage. Increasingly public po... more The science and management of infectious disease are entering
a new stage. Increasingly public policy to manage epidemics
focuses on motivating people, through social distancing policies,
to alter their behavior to reduce contacts and reduce public disease risk. Person-to-person contacts drive human disease dynamics.
People value such contacts and are willing to accept some disease risk to gain contact-related benefits. The cost–benefit trade-offs that shape contact behavior, and hence the course of epidemics, are often only implicitly incorporated in epidemiologicalmodels. This approach creates difficulty in parsing out the effects of adaptive behavior. We use an epidemiological–economic model of disease dynamics to explicitly model the trade-offs that drive person-toperson
contact decisions. Results indicate that including adaptive
human behavior significantly changes the predicted course of epidemics and that this inclusion has implications for parameter estimation and interpretation and for the development of social distancing policies. Acknowledging adaptive behavior requires a shift in thinking about epidemiological processes and parameters.

The paper develops an optimal control model to analyse various management options for infectious ... more The paper develops an optimal control model to analyse various management options for infectious diseases that occur in metapopulations, under both Nash and cooperative behaviour.

Pollen-mediated gene flow is one of the main concerns associated with the introduction of genetic... more Pollen-mediated gene flow is one of the main concerns associated with the introduction of genetically modified (GM) crops. Should a premium for non-GM varieties emerge on the market, ‘contamination’ by GM pollen would generate a revenue loss for growers of non-GM varieties. This paper analyses the problem of pollen-mediated gene flow as a particular type of production externality. The model, although simple, provides useful insights into coexistence policies. Following on from this and taking GM herbicide-tolerant oilseed rape (Brassica napus) as a model crop, a Monte Carlo simulation is used to generate data and then estimate the effect of several important policy variables (including width of buffer zones and spatial aggregation) on the magnitude of the externality associated with pollen-mediated gene flow.

World population and the need for nutritious food continue to grow. For 14 years farmers from a r... more World population and the need for nutritious food continue to grow. For 14 years farmers from a range of countries across the globe have been accessing transgenic technologies to either reduce crop production costs, increase yield and/or to exploit a range of rotational benefits. In 2009 134Mha of transgenic crops were grown. The arable area of the EU 27 is approximately 102 Mha however only about 0.1 Mha of transgenic crops, mainly maize in Spain, is grown in the EU. This is in part due to limited approvals prior to the establishment of a moratorium on the cultivation of transgenic crops. In this paper we estimate the revenue foregone by EU farmers, based on the potential hectarages of IR and HT transgenic crops that have been economically successful elsewhere if they were to be grown in areas of the EU where farmers could expect an overall financial benefit. This benefit would accrue primarily from reduced input costs. We estimate that if the areas of transgenic maize, cotton, soya, oil seed rape and sugar beet were to be grown where there is agronomic need or benefit then farmer margins would increase by between €443 and €929 M/year. It is noted that this margin of revenue foregone is likely to increase if the current level of approval and growth remains low, as new transgenic events come to market and are rapidly taken up by farmers in other parts of the world.

World oilseed trade consists of many closely substitutable commodities, with canola and cottonsee... more World oilseed trade consists of many closely substitutable commodities, with canola and cottonseed as possible alternatives to soya beans for many purposes. Transgenic events in all three crops have been widely adopted, particularly in North and South America, for compelling economic or agronomic reasons. Despite the close attention from organizations concerned about the potential consequences of transgenic crop adoption, there appears to be no substantiated evidence of transgenic DNA in meat or milk products when such crops are fed to livestock. The global area of these transgenic crops continues to increase. No transgenic canola, cotton or soya bean crops are permitted for commercial cultivation in Europe, and although transgenic feed resources are permitted for import, importers risk shipments being denied entry if the traces of an unauthorized transgenic crop are detected. These tight controls can mean that livestock farmers in the EU are disadvantaged due to restricted access to cheaper feed or higher feed costs, and they are thus loosing a degree of competitive advantage. This paper reviews the extent to which transgenic soya beans have become the ‘conventional’ method of cultivation elsewhere, and notes implications this has for livestock nutrition, traceability and economics within the EU. The paper concludes with discussion regarding the implications for the EU of delayed acceptance of newly available transgenic traits.

The concept of sustainable development forms the basis for a wide variety of international and na... more The concept of sustainable development forms the basis for a wide variety of international
and national policy making. World population continues to expand at about
80 M people per year, while the demand for natural resources continues to escalate.
Important policies, treaties and goals underpin the notion of sustainable development.
In this paper, we discuss and evaluate a range of scientific literature pertaining
to the use of transgenic crops in meeting sustainable development goals. It is concluded
that a considerable body of evidence has accrued since the first commercial
growing of transgenic crops, which suggests that they can contribute in all three
traditional pillars of sustainability, i.e. economically, environmentally and socially.
Management of herbicide-tolerant and insect-resistant transgenic crops to minimize
the risk of weeds and pests developing resistance is discussed, together with the
associated concern about the risk of loss of biodiversity. As the world population
continues to rise, the evidence reviewed here suggests it would be unwise to ignore
transgenic crops as one of the tools that can help meet aspirations for increasingly
sustainable global development.

Biosecurity is a great challenge to policy-makers globally. Biosecurity policies aim to either pr... more Biosecurity is a great challenge to policy-makers globally. Biosecurity policies aim to either prevent invasions before they occur or to eradicate and/or effectively manage the invasive species and diseases once an invasion has occurred. Such policies have traditionally been directed towards professional producers in natural resource based sectors, including agriculture. Given the wide scope of issues threatened by invasive species and diseases, it is important to account for several types of stakeholders that are involved. We investigate the problem of an invasive insect pest feeding on an agricultural crop with heterogeneous producers: profit-oriented professional farmers and utility-oriented hobby farmers. We start from an ecological-economic model conceptually similar to the one developed by Eiswerth and Johnson [Eiswerth, M.E. and Johnson, W.S., 2002. Managing nonindigenous invasive species: insights from dynamic analysis. Environmental and Resource Economics 23, 319–342.] and extend it in three ways. First, we make explicit the relationship between the invaded state carrying capacity and farmers' planting decisions. Second, we add another producer type into the framework and hence account for the existence of both professional and hobby farmers. Third, we provide a theoretical contribution by discussing two alternative types of equilibria. We also apply the model to an empirical case to extract a number of stylised facts and in particular to assess: a) under which circumstances the invasion is likely to be not controllable; and b) how extending control policies to hobby farmers could affect both types of producers.

Cotton production in the European Union (EU) is limited to areas of Greece and Southern Spain (An... more Cotton production in the European Union (EU) is limited to
areas of Greece and Southern Spain (Andalusia). The 2004
reform of the EU cotton policy severely affected the profitability
of the crop. In this article we analyze how the introduction of
genetically modified (GM), insect-resistant cotton varieties (Bt
cotton) might help EU cotton farmers to increase profitability and
therefore face the cotton policy reform. We first study farmers’
attitudes toward adoption of Bt cotton varieties through a survey
conducted in Andalusia (Southern Spain). The results show a
positive attitude of Andalusian cotton farmers toward the Bt cotton
varieties. Second, we perform an ex-ante analysis of the
effects of introducing Bt cotton in Andalusia. Finally, we integrate
the analysis of the effects of Bt cotton with the analysis of
the EU cotton reform. Our results show that despite the significant
economic benefits of Bt cotton, the current policy reform is
likely to jeopardize the profitability of cotton production in the
EU.

Luxembourg: Joint Research Centre of the …, Jan 1, 2008

The development of genetically modified (GM) crops has led the European Union (EU) to put forward... more The development of genetically modified (GM) crops has led the European Union (EU) to put forward the concept of ‘coexistence’ to give farmers the freedom to plant both conventional and GM varieties. Should a premium for non-GM varieties emerge in the market, ‘contamination’ by GM pollen would generate a negative externality to conventional growers. It is therefore important to assess the effect of different ‘policy variables’ on the magnitude of the externality to identify suitable policies to manage coexistence. In this paper, taking GM herbicide tolerant oilseed rape as a model crop, we start from the model developed in Ceddia et al. [Ceddia, M.G., Bartlett, M., Perrings, C., 2007. Landscape gene flow, coexistence and threshold effect: the case of genetically modified herbicide tolerant oilseed rape (Brassica napus). Ecol. Modell. 205, pp. 169–180] use a Monte Carlo experiment to generate data and then estimate the effect of the number of GM and conventional fields, width of buffer areas and the degree of spatial aggregation (i.e. the ‘policy variables’) on the magnitude of the externality at the landscape level. To represent realistic conditions in agricultural production, we assume that detection of GM material in conventional produce might occur at the field level (no grain mixing occurs) or at the silos level (where grain mixing from different fields in the landscape occurs). In the former case, the magnitude of the externality will depend on the number of conventional fields with average transgenic presence above a certain threshold. In the latter case, the magnitude of the externality will depend on whether the average transgenic presence across all conventional fields exceeds the threshold. In order to quantify the effect of the relevant ‘policy variables’, we compute the marginal effects and the elasticities. Our results show that when relying on marginal effects to assess the impact of the different ‘policy variables’, spatial aggregation is far more important when transgenic material is detected at field level, corroborating previous research. However, when elasticity is used, the effectiveness of spatial aggregation in reducing the externality is almost identical whether detection occurs at field level or at silos level. Our results show also that the area planted with GM is the most important ‘policy variable’ in affecting the externality to conventional growers and that buffer areas on conventional fields are more effective than those on GM fields. The implications of the results for the coexistence policies in the EU are discussed.

One component of biosecurity is protection against invasive alien species, which are one of the m... more One component of biosecurity is protection against invasive alien species, which are one of the most important threats worldwide to native biodiversity and economic profitability in various sectors, including agriculture. However, agricultural producers are not homogeneous. They may have different objectives and priorities, use different technologies, and occupy heterogeneous parcels of land. If the producers differ in terms of their attitude towards invasive pests and the damages they cause, there are probably external effects in the form of pest spread impacts and subsequent damages caused. We study such impacts in the case of two producer types: profit-seeking professional producers and utility-seeking hobby producers. We show that the hobby producer, having first set a breeding ground for the pest, under-invests in pest control. We also discuss potential policy instruments to correct this market failure and highlight the importance of considering different stakeholders and their heterogeneous incentives when designing policies to control invasive alien species.

Environmental Science & Policy, 2016

… Congress, August 30- …, Jan 1, 2011

Pollen-mediated gene flow is one of the main concerns associated with the introduction of genetic... more Pollen-mediated gene flow is one of the main concerns associated with the introduction of genetically modified (GM) crops. Should a premium for non-GM varieties emerge on the market, ‘contamination’ by GM pollen would generate a revenue loss for growers of non-GM varieties. This paper analyses the problem of pollen-mediated gene flow as a particular type of production externality. The model, although simple, provides useful insights into coexistence policies. Following on from this and taking GM herbicide-tolerant oilseed rape (Brassica napus) as a model crop, a Monte Carlo simulation is used to generate data and then estimate the effect of several important policy variables (including width of buffer zones and spatial aggregation) on the magnitude of the externality associated with pollen-mediated gene flow.

Luxembourg: Joint Research Centre of the …, Jan 1, 2008

Globally there have been a number of concerns about the development of genetically modified crops... more Globally there have been a number of concerns about the development of genetically modified crops many of which relate to the implications of gene flow at various levels. In Europe these concerns have led the European Union (EU) to promote the concept of ‘coexistence’ to allow the freedom to plant conventional and genetically modified (GM) varieties but to minimise the presence of transgenic material within conventional crops. Should a premium for non-GM varieties emerge on the market, the presence of transgenes would generate a ‘negative externality’ to conventional growers. The establishment of maximum tolerance level for the adventitious presence of GM material in conventional crops produces a threshold effect in the external costs.

The existing literature suggests that apart from the biological characteristics of the plant under consideration (e.g. self-pollination rates, entomophilous species, anemophilous species, etc.), gene flow at the landscape level is affected by the relative size of the source and sink populations and the spatial arrangement of the fields in the landscape. In this paper, we take genetically modified herbicide tolerant oilseed rape (GM HT OSR) as a model crop. Starting from an individual pollen dispersal function, we develop a spatially explicit numerical model in order to assess the effect of the size of the source/sink populations and the degree of spatial aggregation on the extent of gene flow into conventional OSR varieties under two alternative settings. We find that when the transgene presence in conventional produce is detected at the field level, the external cost will increase with the size of the source area and with the level of spatial disaggregation. On the other hand when the transgene presence is averaged among all conventional fields in the landscape (e.g. because of grain mixing before detection), the external cost will only depend on the relative size of the source area. The model could readily be incorporated into an economic evaluation of policies to regulate adoption of GM HT OSR.

In this article we investigate the effects of the European CAP reform on a selection of arable cr... more In this article we investigate the effects of the European CAP reform on a selection of arable crops in England, both at a regional and national level. The results show that the CAP reform will push farmers to adjust to the new market conditions, which will cause a further restructuring of the English agricultural business sector. Our results show that, under the new market conditions, economically-small farms will increase their output by allocating more land to cereals, whereas economically-large farms will need to decrease land allocated to cereals to reduce production costs and achieve better returns.

Pollen-mediated gene flow is one of the main concerns associated with the introduction of genetic... more Pollen-mediated gene flow is one of the main concerns associated with the introduction of genetically modified (GM) crops, since growers of GM varieties normally do not take into account its possible impact on conventional and organic growers therefore generating negative externalities. Should a premium for non-GM varieties emerge on the market, 'contamination' with GM pollen would generate a revenue loss for growers of non-GM varieties. The existence of such externalities has led the European Union (EU) to put forward the concept of coexistence in order to guarantee farmers' freedom to plant both conventional and GM varieties without generating economic losses to conventional farmers. The first part of this paper develops a simple economic model analysing the problem of pollen-mediated gene flow as a particular kind of production externality. The model, although simple, provides useful insights into the policy needed to regulate coexistence. Since pollen-mediated gene flow is distancedependent, the externalities will depend on the spatial structure of GM adoption in the landscape. The second part of the paper, taking GM herbicide tolerant oilseed rape (Brassica napus) as a model crop, uses a Monte Carlo experiment to generate data and then estimate the effect of some important policy variables (i.e. number of GM and conventional fields in the landscape, width of buffer zones and spatial aggregation) on the magnitude of the externality associated with pollen-mediated gene flow. Our results show that buffer areas on conventional fields are more effective than those on GM fields and that the degree of spatial aggregation exerts the largest marginal effect on the externality to conventional growers. The implications of the results for the coexistence policies in the EU are then discussed.