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EFFECTS OF THE MANAGEMENT OF FIELD SCALE RELEASES OF GENETICALLY-MODIFIED HERBICIDE-TOLERANT CROPS ON THE ABUNDANCE AND DIVERSITY OF FARMLAND WILDLIFE

Interim Report

11 November 1999

Edited by

Les Firbank¹

Written by

John Bater², Helaina Black¹, Gill Champion², Roger Daniels¹, Alan Dewar², Margaret Dixon¹, Les Firbank¹, Peter Greenslade¹, Cathy Hawes³, Matt Heard¹, Mark Hill¹, Peter Lutman², Martin Maudsley², Mike May², Juliet Osborne¹, John Pidgeon², Joe Perry², Peter Rothery¹, David Roy¹, Rod Scott¹, Geoff Squire³, John Watkins¹, Ian Woiwod²

Executive summary

1. The main purpose of this project is to test the null hypothesis that there are no significant differences between the biodiversity associated with the management of GM winter oilseed rape / spring oil seed rape / maize crops that are tolerant to herbicides and comparable non-GM crops at the farm scale. Here we report on progress in the period April — September 1999.
2. The approach is to compare indicators of soils, vegetation and invertebrates for land used for GM crops with the same indicators in comparable non-GM crops. Effects on following crops are also assessed. It is assumed that any effects on biodiversity will arise from changes in crop and field management, and not as a direct result of the use of GM technology. Our methodology is the same for all three crops, as far as possible. The experiment does not address gene flow, as this was assessed separately by the National Institute of Agricultural Botany.
3. Virtually all of the work so far has been concerned with the development of the methodology. Field trials and new analyses have been used to ensure that the methods are both rigorous and yet practicable. The field trials have included maize and spring rape sites, using both split and paired fields. The data from these trials are proving to be an invaluable source of information for the conduct of these trials. Site selection will be on the basis of selecting from a pool of possible sites selected by SCIMAC.
4. New analyses confirm for adequate replication, planting should proceed at about 25 farms per crop per year. The current weight of evidence suggests that a split field approach is likely to be more appropriate to the indicators we are recording, and simpler to achieve in practice, than a paired field approach.
5. The collection of data on farm management has been trialed. Whilst we make no suggestion that the field management has been manipulated in any way, we still need greater standardisation on the provision of agronomic advice to farmers.
6. Methods of assessing biodiversity have been developed during the season. We confirm that we should focus on species groups that are indicative of longer term change, and of change higher up the food chain.

In particular, we will monitor:

Vegetation in and around the field
Soil seed bank
Slugs and snails
Arthropods on vegetation (with particular reference to plant bugs, pringtails, and caterpillars of butterflies, moths and sawflies)
Carabid beetles and ground-dwelling arthropods
Bees and butterflies

The methodologies still need some refinement, notably in terms of finalising appropriate sampling intensities and timings.

7. The field experiments in 1999 comprised four sites with maize and three with spring oil seed rape. Of these sites, one was taken out of the experiment by the farmer, and there was extensive damage to two other sites by protestors, although we continued to monitor them.
8. The field studies for the winter rape trials have begun. There are two paired and one split field study sites. Seed bank sampling has already taken place. Work this autumn will concentrate on finalising sampling and data management protocols. We also need to plan the spring 2000 plantings as soon as possible.
9. The research project is of great public interest, and while we strongly wish to be pro-active and positive about our work within the public debate, this is difficult given that our priority must remain firmly focussed on the conduct of the experiment itself.

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¹The Institute of Terrestrial Ecology
²The Institute of Arable Crops Research
³The Scottish Crop Research Institute

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Published 23 December 1999

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