Two different approaches to ecological risk assessment of genetically modified plants are discussed. The first is an intuitive approach of summarising the scientific knowledge on the specific genetically modified plant, called "the concept of familiarity". The other approach is based on the estimation of probabilities of specific ecological scenarios, which we will call "scientific risk assessment". In the conclusion we will advocate that the use of scientific risk assessment for ecological risk assessment is the superior methodology.
The question of whether or not transgenic plants should be used commercially cannot only be decided upon using agronomic arguments. Genetically modified plants (GMP"s) are a public concern, and the public wants to know how safe this new technology is - the scientific answer to such a demand is risk assessment.
Risk assessment of GMP"s has developed from the first comprehensive review article presented in the late eighties (Tiedje et al. 1989). This review was primarily based on speculations and its focus was primarily on agronomic concerns (creation of new pests etc.) and on the structure of international co-operation. The authors concluded that more interdisciplinary research was needed in order to evaluate benefits and risks of biotechnology. Since then, scientists have gone through a period of optimism concerning the risks of GMP"s, exemplified by Crawley 1992, into a phase of growing concerns together with the increasing amount of relevant data (Tomiuk et al. 1996). In the mid-nineties the discussion was further expanded from a "simple" scientific debate of biological consequences of releases to include ethical considerations (eg, Potthast 1996). At the same time the regulatory and legal aspect of commercialisation became a major issue (Tomiuk et al. 1996). Today we are at a stage where a lot of relevant data has been collected but no internationally standardised and consistent schemes, test procedures and concepts have been fully developed associated with commercial use of GMP"s (Strandberg et al. 1998).
In some cases introduction of new species or genotypes to an area is an irreversible process. If a plant is introduced into a natural habitat it may not be practically possible to remove it again. Therefore, it is important to make an assessment of possible ecological risks of a GMP before it is released for commercial growing. Here we will briefly present two different approaches to ecological risk assessment, one, using an intuitive approach of summarising the scientific knowledge on the specific GMP, called "the concept of familiarity", and another, based on the estimation of probabilities of specific ecological scenarios, which we will call "scientific risk assessment". In the conclusion we will advocate that the use of scientific risk assessment for ecological risk assessment is the superior methodology.
