The present work was initiated in autumn 1991, with the aim to compile a catalogue of test methods useful for the risk assessment of transgenic plants, hereafter synonymously referred to as gene- tically modified plants (GMP). The steering group decided that the methods included in the catalogue should be based on recent litera- ture with the main emphasis on competition, establishment, and eco- system effects. The main user groups for the catalogue are scientists and students working in plant ecology and risk assessment and ad- ministrators with responsibility for the legislation of transgenic plants. A broad range of ecological and genetic methods in contem- porary use has been included in the catalogue. It is our hope that the present work will also be useful as a reference for experimental research in general plant population ecology and genetics. Most of the methods covered in the catalogue do indeed originate from these research fields.We would like to thank the members of the steering group, Hans Erik Svart and Smen Mark Jensen from the National Forest and Nature Agency, and Kaj Juhl Madsen from the Danish Environmen- tal Protection Agency for their support and assistance in initiating this work, and for valuable comments during its preparation. Several people gave highly valuable technical assistance: Lilian Mex- J0rgensen, Lone M0ller, Anna Marie Plejdrup, Karsten Rasmussen and Bodil Thestrup. Caroline Burke, Winnie Meilstrup, and Lone Th0gersen generously helped in correcting the language. Kathe M0gelvang is acknowledged for the drawing on the front cover.
