Jeremy Sweet

Assessment of risk of insect-resistant transgenic crops to nontarget arthropods

An international initiative is developing a scientifically rigorous approach to evaluate the potential risks to nontarget arthropods (NTAs) posed by insect-resistant, genetically modified (IRGM) crops. It adapts the tiered approach to risk assessment that is used internationally within regulatory toxicology and environmental sciences. The approach focuses on the formulation and testing of clearly stated risk hypotheses, making maximum use of available data and using formal decision guidelines to progress between testing stages (or tiers). It is intended to provide guidance to regulatory agencies that are currently developing their own NTA risk assessment guidelines for IRGM crops and to help harmonize regulatory requirements between different countries and different regions of the world.

Risk assessment of GM plants: avoiding gridlock?

Cultivation of genetically modified crops is presently based largely on four crops containing few transgenes and grown in four countries. This will soon change and pose new challenges for risk assessment. A more structured approach that is as generic as possible is advocated to study consequences of gene flow. Hazards should be precisely defined and prioritized, with emphasis on quantifying elements of exposure. This requires coordinated effort between large, multidisciplinary research teams.

Persistence of seeds from crops of conventional and herbicide tolerant oilseed rape (Brassica napus)

A series of rotation experiments at five sites over four years has explored the environmental and agronomic implications of growing herbicide tolerant oilseed rape and sugar beet. This paper reports on the population dynamics of volunteer rape (Brassica napus). The experiments compared four winter oilseed rape (WOSR) cultivars: a conventional cultivar (Apex) and three developmental cultivars either genetically modified (GM) to be tolerant to glyphosate or glufosinate, or conventionally bred to be tolerant to herbicides of the imidazolinone group. Seed losses at harvest averaged 3575 seeds m−2 but ranged from less than 2000 up to more than 10 000 seeds m−2. There was a rapid decline in seed numbers during the first few months after harvest, resulting in a mean loss of seeds of 60%. In subsequent seasons, the seedbank declined much more slowly at four of the five sites (ca 20% per year) and the models predicted 95% seed loss after approximately 9 years. Seed decline was much faster at the fifth site. There were no clear differences between the four cultivars in either the numbers of seeds shed at harvest or in their subsequent persistence. The importance of the persistence of GM rape seeds, in the context of the coexistence of GM and non-GM crops and the role of good management practices that minimize seed persistence, are discussed.

A mathematical model of exposure of non- target Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis (Bt), toxic to lepidopteran target pests such as Ostrinia nubilalis. An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt-containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality–dose relationship was integrated with a dose–distance relationship to estimate mortality both within the maize MON810 crop and within the field margin at varying distances from the crop edge. Mortality estimates were adjusted to allow for physical effects; the lack of temporal coincidence between the susceptible larval stage concerned and the period over which maize MON810 pollen is shed; and seven further parameters concerned with maize agronomy and host-plant ecology. Sublethal effects were estimated and allowance made for aggregated pollen deposition. Estimated environmental impact was low: in all regions, the calculated mortality rate for worst-case scenarios was less than one individual in every 1572 for the butterflies and one in 392 for the moth.

Estimating the effects of Cry1F Bt‐maize pollen on non‐target Lepidoptera using a mathematical model of exposure

Summary 1. In farmland biodiversity, a potential risk to the larvae of non‐target Lepidoptera from genetically modified (GM) Bt‐maize expressing insecticidal Cry1 proteins is the ingestion of harmful amounts of pollen deposited on their host plants. A previous mathematical model of exposure quantified this risk for Cry1Ab protein. We extend this model to quantify the risk for sensitive species exposed to pollen containing Cry1F protein from maize event 1507 and to provide recommendations for management to mitigate this risk. 2. A 14‐parameter mathematical model integrating small‐ and large‐scale exposure was used to estimate the larval mortality of hypothetical species with a range of sensitivities, and under a range of simulated mitigation measures consisting of non‐Bt maize strips of different widths placed around the field edge. 3. The greatest source of variability in estimated mortality was species sensitivity. Before allowance for effects of large‐scale exposure, with moderate within‐crop host‐plant density and with no mitigation, estimated mortality locally was <10% for species of average sensitivity. For the worst‐case extreme sensitivity considered, estimated mortality locally was 99·6% with no mitigation, although this estimate was reduced to below 40% with mitigation of 24‐m‐wide strips of non‐Bt maize. For highly sensitive species, a 12‐m‐wide strip reduced estimated local mortality under 1·5%, when within‐crop host‐plant density was zero. Allowance for large‐scale exposure effects would reduce these estimates of local mortality by a highly variable amount, but typically of the order of 50‐fold. 4. Mitigation efficacy depended critically on assumed within‐crop host‐plant density; if this could be assumed negligible, then the estimated effect of mitigation would reduce local mortality below 1% even for very highly sensitive species. 5.  Synthesis and applications. Mitigation measures of risks of Bt‐maize to sensitive larvae of non‐target lepidopteran species can be effective, but depend on host‐plant densities which are in turn affected by weed‐management regimes. We discuss the relevance for management of maize events where cry1F is combined (stacked) with a herbicide‐tolerance trait. This exemplifies how interactions between biota may occur when different traits are stacked irrespective of interactions between the proteins themselves and highlights the importance of accounting for crop management in the assessment of the ecological impact of GM plants.

The usefulness of a mathematical model of exposure for environmental risk assessment.

We respond to the Comment of Lang et al . [[1][1]] regarding our mathematical model [[2][2]] of exposure of non-target Lepidoptera to Bt -maize pollen expressing Cry1Ab within Europe. Lang et al . remark on the degree to which the model was subject to uncertainty. Perry et al . [[2][2]] did indeed

Farm questionnaires for monitoring genetically modified crops: a case study using GM maize.

Monitoring is a statutory requirement for the cultivation of genetically modified (GM) crops in the European Community. Questionnaires for farmers to report on observations of effects linked with the cultivation of GM crops can form a useful part of a monitoring regime. A questionnaire for GM maize (Zea mays L.) was designed, with questions focusing on potential effects related to the GM maize grown, as well as on background information about cultivation methods and on individual field situations. In this paper we present the methodological approach of the monitoring regime, the structuring of the data, and the contents and structure of the questionnaire. The statistical requirements and background for an appropriate evaluation and interpretation of the data are described. Results of interviews made from 2001 to 2005 are also presented. It is envisaged that this approach will be developed for monitoring other cultivated GM plants and traits, and may be applicable in monitoring certain non-farmed environments.

Concepts for General Surveillance of Genetically Modified (GM) Plants: The EFSA position

Abstract.The European Food Safety Authority (EFSA) is requested to assess the scientific quality of Post Market Environmental Monitoring (PMEM) plans submitted with each application for deliberate release of genetically modified (GM) plants according to part C of EU Directive 2001/18/EC and according to EU Regulation 1829/2003. PMEM aims at identifying unanticipated adverse effects on human health or the environment which could arise directly or indirectly from GM plants. PMEM is composed of case-specific monitoring and general surveillance. Case-specific monitoring is not obligatory but may be required to verify the environmental risk assessment. A general surveillance plan is compulsory and aims at identifying unanticipated adverse effects. General surveillance is not hypothesis-driven but is a general overseeing of the environment making use of existing surveillance systems in addition to developing more focused monitoring systems (e. g. farm questionnaires). Data quality, management and statistical analysis are of high importance in the design of general surveillance plans. Comparison should be made with appropriate baseline data. The EFSA GMO Panel also makes a number of recommendations for the management and conduct of PMEM by both applicants and risk managers.Zusammenfassung.Die Europäische Lebensmittelbehörde (EFSA) ist aufgefordert, die wissenschaftliche Qualität von Plänen zur Umweltbeobachtung (PMEM) von Inverkehr-gebrachten gentechnisch veränderten (GM) Pflanzen zu bewerten, wenn sie als Bestandteil von Inverkehrbringensanträgen nach der Direktive 2001/18/EC an die EFSA weitergeleitet werden. Die Zuständigkeit nach Verordnung 1829/2003 ist in jedem Antragsfall gegeben. Die PMEM ist auf die Identifizierung nachteiliger Effekte auf die menschliche Gesundheit und die Umwelt gerichtet, die direkt oder indirekt von GM-Pflanzen verursacht werden könnten. PMEM ist gegliedert in fallspezische und allgemeine Beobachtung. Die fallspezifische Beobachtung ist nicht obligatorisch, sondern richtet sich nach dem Ergebnis der Umweltverträglichkeitsprüfung. Die allgemeine Beobachtung ist immer notwendig und fokussiert sich auf die Erkennung von unvorhergesehen nachteiligen Effekten. Die allgemeine Beobachtung ist nicht von Hypothesen geleitet, sondern betrachtet übersichtsweise die Umwelt mit Hilfe bestehender Beobachtungssysteme zusätzlich zur Einrichtung fokussierter Erhebungssysteme wie landwirtschaftlicher Betriebsfragebögen. Die Datenqualität, das Management und die Analyse sind von großer Bedeutung für das Design der allgemeinen Beobachtungspläne. Vergleiche sollten mit angemessenen Grundlagendaten durchgeführt werden. Das wissenschaftliche Gremium der EFSA gibt zahlreiche Empfehlungen für das Management und die Durchführung von PMEM für Antragsteller und Risikomanager.

A framework for stakeholder engagement during systematic reviews and maps in environmental management

People have a stake in conservation and environmental management both for their own interests and the sake of the environment itself. Environmental decision-making has changed somewhat in recent decades to account for unintentional impacts on human wellbeing. The involvement of stakeholders in environmental projects has been recognised as critical for ensuring their success and equally for the syntheses of evidence of what works, where, and for whom, providing key benefits and challenges. As a result of increased interest in systematic reviews of complex management issues, there is a need for guidance in best practices for stakeholder engagement. Here, we propose a framework for stakeholder engagement in systematic reviews/systematic maps, highlighting recommendations and advice that are critical for effective, efficient and meaningful engagement of stakeholders. The discussion herein aims to provide a toolbox of stakeholder engagement activities, whilst also recommending approaches from stakeholder engagement research that may prove to be particularly useful for systematic reviews and systematic maps.

Out-crossing between genetically modified herbicide-tolerant and other winter oilseed rape cultivars

Out-crossing between genetically modified herbicide-tolerant (GMHT) and non-GM rape cultivars was studied using GMHT source field plots of approximately 0.8 ha. Levels of cross-pollination between adjacent fully fertile rape varieties declined rapidly with increasing distance from the interface between plots. A varietal association with low levels of male sterility showed higher levels of out-crossing than other varieties. Out-crossing data were used to compare negative exponential and inverse power-law models for their fit to describe the observed relationship between cross-pollination and distance from source. Results showed that the inverse power-law model provided a better fit of the data.