2 Testing the null hypothesis
2.1 Overall approach
The approach is to compare indicators of soils, vegetation and invertebrates on land used for GM crops with the same indicators for comparable non-GM crops. Effects on following crops grown on the land in subsequent seasons 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. Indeed, our approach would be identical for herbicide-tolerant crops resulting from more conventional breeding methods. Our methodology is the same for all crops, as far as possible. The experiment does not address gene flow, as this was assessed separately by NIAB.
The basic approach is to measure differences in biodiversity between an area with a GM crop and one with a comparable non-GM crop, placed close together on the same site. Sites are chosen to represent fully the range of variation in soil, climate, species occurrence and farm management that is likely to be found in the commercial growing of GM crops. The pairing of the GM and non-GM areas within each site ensures this variation is accounted for within the analyses, and does not affect the comparison between the crops. The form of comparison between the crops is direct, and so requires no information on changes in biodiversity before and after sowing; there is therefore little need for baseline data. Within-site variation, that might cause a difference between the pair of areas in their potential for biodiversity, will be allowed for by measurements of the soil seed bank and surrounding habitats.
Both GM and non-GM farming systems are managed according to current commercial practice, although within this constraint, management practices will be kept constant. The non-GM variety is matched to the GM variety in its development as far as possible. Thus the design looks at differences in biodiversity between crops, but also between following crops, including any due to differences in the rotation, provided that these differences are a consequence of the two varieties of crops being used.
The study involves recording both how the crops are managed, and the effects of the crops and their management on a range of indicators of biodiversity. We concentrate on those animal and plant indicators that are likely to be sensitive to changes in farming system, that are indicative of other groups not directly assessed, and can be considered to be indicative of slower and larger-scale processes not readily detected within the experiment directly.
A study undertaken as part of the Tender suggested that an appropriate level of replication would be achieved by planting at about 25 pairs of sites per crop per year, in years 2-4, with a smaller number in the first year to develop the methodologies. The analysis will consider each biodiversity indicator in turn, and also examine relationships between indicators, taking into account data from other relevant studies.
2.2 Developing the methodologyVirtually all of the work so far has been concerned with the development of the methodology. Field trials and new analyses have been used to gain experience about how to test the null hypotheses using methods that are both rigorous, yet practicable. The field trials have been on maize and spring rape sites, using both split and paired field configurations. The data are proving to be an invaluable source of information for the conduct of these trials.
2.3 Farm and field selectionThe sites for the spring planting were selected through agreement between individual farmers and AgrEvo, the suppliers of the seed, operating on behalf of SCIMAC. This process will continue. However, in itself, it does not guarantee that that the range of farms will be representative of those farms most likely to grow the crops under commercial conditions. Therefore, we wish to be provided by SCIMAC with a very wide choice of potential sites, from which we would select samples to ensure representative ranges of size, intensity of management, geography, and so on. We will collect data about the national context of the farm from existing national databases, and data about the more immediate context of the fields, their margins, boundaries and surrounding countryside through mapping on site; these may all be covariates in the analyses. We will allocate GM and non-GM treatments to units at random from an appropriate pair of units. The Consortium would therefore take responsibility for site and treatment selection, within the range of options provided by SCIMAC.
2.4 Consideration of sample sizeThe importance of determining sample size was emphasised by the Steering Committee at its first meeting. It has to be large enough to be able to detect the desired levels of change, but too large and resources are being wasted. We therefore established a working group between statisticians on the project team and on the Steering Committee. The method was to use simulated data to explore the power of different sample sizes to reveal genuine ecological differences between the GM and non-GM treatments. Broadly speaking, the model included between-farm differences, allowed for low counts and incorporated dependence between variance of counts and mean density. Our interpretation is that the results will broadly corroborate the previously calculated powers, suggesting that around 25 sites per crop should be planted per year, including some provision for wastage of sites as a result of farmers withdrawing from the experiment, or damage from activists.
2.5 Consideration of split versus paired fields
The design proposed in our Tender was a randomised block design with two treatments per block and approximately 25 blocks lasting one year (plus follow up recording); this design to be repeated, with fresh randomisation, in future years. The experimental unit proposed in the Tender was a field of about 10 ha. The blocks would be represented by whole farms, and the within-block units by whole fields. However, the Steering Committee considered the possibility that inter-field variation may be too great, and that the two halves of the same fields should be used as the experimental units. In other words, that split fields may be preferable to paired fields. The overall design remains unchanged; the issue is one of size and location of the experimental units.
The Steering Committee and the Consortium both recognise that there are arguments in favour of both the paired and split field approaches. The split fields may control variability due to previous management and cropping history, but the larger field size requirement may introduce bias in farm selection to larger units, and there may be interference between treatments.
This issue was also considered by the working group of statisticians. The approach was to analyse vegetation data from some of our spring 1999 sites, along with existing data similar to those we will be collecting.
Data from the MAFF LINK project were considered, but proved unsuitable, because effects could not be estimated independently of confounding year x treatment interactions, and also because there were very few instances of rotations that included the crops with which we are concerned. Data from Loddington, collected by The Game Conservancy Trust, were also not suitable for the analysis of weeds, but were more suitable for invertebrates. These data show that within split-fields we might expect similar levels of variability to those that we have assumed in our power calculations. Also, that while for many fields the variability between paired fields would not be much greater, occasionally the difference could really be very great, and the paired-field would then be much less efficient. However, in the Loddington data, fields had not been matched, and that might have inflated between-field variability. In addition, we would expect less variability in our trials because our within-unit sampling effort will be much greater. The weed data from our own sites give little additional information regarding the choice of design, because of the small number of sites available. The subcommittee needs to consider these results. However, we suspect that they shed little new light on the debate, as the results were much as expected on the basis of existing knowledge.
Other new information has come to light, however. Firstly, the more detailed consideration of the protocols for more mobile species has clarified that for these we will be considering the choice of use of the crops, rather than attempt to estimate population sizes. A split field approach is actually more suitable for butterflies and bees. Secondly, experience with farmers has shown that they can rarely offer well-matched fields in practice, that there can be problems in randomising which field receives which treatment, and that different fields may diverge in management to too great an extent in subsequent years. The statistics working group will consider this issue, and report to the Steering Committee. The Consortium itself has come to a view that we now recommend split fields, with the caution that we must ensure that the sample units are neither so large that they exclude certain types of farm, nor so small that edge effects begin to predominate.
The project requires an assessment of how GMHT cropping will affect the management of farming systems and the agricultural landscape. We will address this requirement by allowing the GMHT and non-GMHT cropping systems to be managed along appropriate commercial lines. Individual farms will provide both the GM and the paired non-GM sites.
This means that the GMHT cropping systems will be managed under SCIMAC guidelines. Changes to the rotations, or to field margin management, will therefore be allowed. The only constraints we wish to impose are that the two varieties being considered are as similar as possible in traits other than the herbicide tolerance, especially phenology and crop structure, and that where non-herbicide treatments are imposed on both GMHT and the local control, they should be applied at the same time.
The Steering Committee has recognised the clear need for robust validation of the range and nature of the herbicide and other management regimes used by farmers in the farm-scale evaluations. We have been piloting a protocol for collecting farm management records for the period prior to, during and after the test cropping year. The information will include the type of farm and its management, prior cropping of the trial fields, historical records of inputs for relevant crops, actual inputs and actions on the monitored fields and pesticide inputs and management changes resulting from the growing of the test crops. The data will be used as covariates in analyses, to classify the farm management type (eg high input, ICM etc) and to identify any major changes from previous years. At the end of the season, if a split field design is used, the farmer will be asked whether, in a commercial situation, growing the GM crop might have led to a change in subsequent management of the different halves of the field. These data will form the basis of any study on the representativeness of pesticide practices.
We certainly found no evidence that farmers or their advisors were modifying advice and management to influence the results. However, the issue of appropriate sources of agronomic advice to the farmers is still less than perfectly resolved, as we do not yet have systems for ensuring that advice to farmers comes from a BASIS-trained advisor who is independent from SCIMAC while working within their guidelines.
Crop growth stage is assessed at every survey visit. We do not currently undertake estimates of yield, other than by asking farmers for their own estimates.
2.7 Indicators of biodiversity
Biodiversity is defined as the range of variation in living creatures, at genetic, population and community scales, quantified using data on the relative abundance of members of each type collected at the appropriate scale. In practice, such variation cannot be recorded for all species in a system, and so simplifying assumptions must be made. The level of recording is vastly simplified if genetic variation is ignored — justifiable in this study. Secondly, the level of recording is simplified further if indicators of biodiversity are selected to represent particular species groups. Furthermore, indicators are required for processes that may lead to significant ecological shifts that cannot be detected directly within the limited time and spatial scales for the project. These ideas are recognised within the instructions to tender; priority is to be given to species groups that do not forage over wide areas or occupy higher trophic levels, concentrating on higher plants and invertebrates. Amphibia, birds and mammals will not be monitored directly, but inferences will be made on possible effects on these groups.
Our fundamental approach is to contrast indicators of biodiversity between GMHT and non-GMHT cropping systems. However, while reporting these effects, some can be placed into the context of national recording schemes (notably plants and butterflies) that can help show the relationships between the biodiversity associated with the study sites and arable areas in general. Secondly, some data can feed directly into the BAP process, especially the presence of BAP-listed species.
2.7.1 The choice of indicators
The plans for the project in the Tender addressed a range of plant and invertebrate groups. The Steering Committee had considered the plant and invertebrate monitoring protocols presented by the contractors to be generally sound. It was felt that the inclusion of a protocol for sampling Collembola (springtails), weed seed return and possibly additional soil organisms (including micro-organisms) should be seriously considered. Collembola at least may be included using existing sampling methods.
Protocols for virtually all of the proposed indicators have been tested in the field, and the points raised by the Committee have been carefully considered. As a result some changes have been made, in terms of both the choice of indicators and the methods of field recording that are being used. We have tended to oversample, on the grounds that it will then be easier to establish the most efficient sampling regimes. This task is well on the way to completion for most protocols, but there still remains work to integrate the needs of individual protocols across the whole study.
Soil seed bank
The actual weed flora present at any time is typically only 1% to 10% of the total seedbank, whose abundance ranges between 1,000 and 1,000,000 seeds in a square metre of field down to plough depth. The species that germinate from the seedbank are the ones most stimulated by the environment during seedbed preparation and least harmed by current weed management. Seedbanks in arable land are therefore a more reliable indicator of potential diversity and future weed problems than are the weeds present in any season. While the differential use of herbicide in GM and non-GM crops is likely to affect the seed cycle, crops such as oilseed rape (particularly) shed seed that can become part of the seedbank and therefore alter its composition.
The purpose of seedbank studies in these trials is -
to detect differences caused by GM and non-GM treatments in the composition and abundance of buried seed;
to estimate the likely implications of any effects for the future biomass and habitat in the weed flora;
to make a rapid assessment of the background seedbank population of a field, and thereby to identify sites that are rich or poor in plant diversity.
The final point above partly addresses one of the concerns of the Steering Committee on the need to include weedy sites that contribute disproportionately to the total arable diversity: given early knowledge of such diverse sites, it will be possible to direct attention to them as required. A further point raised by the Steering Committee was the need for measurements of seed rain, rather than, or in addition to, the seedbank. It was decided that (a) sufficient background was available on seedbanks to enable us to place the measurements in the trials in a wider context and (b) the measure of weed biomass just before harvest would give an appropriate indicator of seed return (see below).
A general methodology exists for seedbank studies. The purpose of preliminary studies in the present experiment is to refine logistics and determine the number and location of measurements needed to define change in broad but functional attributes of the seedbank. Seedbank records have been collected from fields of spring oilseed rape, maize and winter oilseed rape. These, together with existing data on the UK seedbank, will be analysed in order to confirm a set of criteria that will adequately define the seedbank in these trials; define the minimum number and optimum location of samples that will reveal statistically significant effects through these criteria; and estimate the best time for re-sampling to observe long-term effects.
Vegetation
Vegetation in the crop is sampled on three occasions in the first season — before spraying, after both GM and conventional crop have received herbicide and the weeds have wilted, and at crop maturity. The first two samples are counts of seedlings and young plants in a 0.5-m square, identified to species. The third sample is a biomass sample, with removal of plants in a 1-m square, sorting, identification, drying and weighing. These data will be used to provide estimates of seed return using existing experimental data (and new data if required). In the season following harvest of the GM crop, seedlings will be counted again in the same locations. If significant differences are detected, seedlings will be counted in the following season. Vegetation sampling in the crop is based on a design
2 treatments x
12 transects from the crop edge x
5 quadrats per transect (reduced to 2 relatively large quadrats per transect for biomass sampling).Vegetation sampling on the field margin is designed to fit in with sampling of invertebrates. The field margin is defined as the non-cropped area between the field boundary and the crop. All species present in a 10 x 1 m quadrat are recorded, together with an estimate of cover. The field boundary is defined as a physical feature which is an interface between the margin and other land cover types (e.g. hedge, ditch). Where no such feature exists, a 10 x 1 m quadrat is taken in the adjacent land cover (e.g. cereal field). Margins and boundaries will be recorded on three occasions during the summer. Observers are asked to comment on whether there are signs of plant necrosis due to spray drift and to record the species in flower. The following design will be used.
2 treatments x
3 positions on the edge of the field x
2 positions relative to the crop (margin and boundary as defined above).Terrestrial Gastropods (Slugs and Snails)
Slugs and snails are generalist herbivores, which are known to be influenced by and to exert influence on the composition of plant communities. Slugs are known to be affected by a range of farming practices. Several species of snails of conservation interest inhabit field margins and could be affected as a consequence of any changes in field margin plant communities resulting from herbicide drift. Because slugs and snails are relatively immobile, any changes at a field scale resulting from the growing of GM crops will not be obscured by movement of individuals, as with flying insects.
Monitoring will be done at each site once in spring and once in autumn each year. Sampling for slugs and snails within the crop and in field margins will be with unbaited refuge traps. In addition snails will be sampled in field margins using timed searches. All individuals will be identified to species.
Arthropods on vegetation
Insects and other arthropods are often the primary consumers of the aerial parts of crops and other plants within the field and the field margin. They will therefore reflect the ecological impact that GM crops may have on the wider environment. Associated with the primary consumers will be other, more mobile, arthropods that feed on them, which are in turn fed upon, either by larger insects or birds. However, the mobility of the organisms at the top of the food chain makes it difficult to assess any wider impact that GM crops may have on their abundance, even at the field scale, hence the need to use indicator species at lower trophic levels.
We have concluded that the most useful indicator groups of invertebrates for our purposes are plant bugs (Heteroptera), springtails (Collembola) and the caterpillars of butterflies, moths and sawflies. These groups will be identified to species where possible. All invertebrates will be collected from each field or split-field using Vortis suction samplers in the field margin, headland and within the crop, placed adjacent to the vegetation sample locations. Other arthropods will also be extracted from the samples and sorted into groups such as spiders, flies, beetles, wasps etc. Total invertebrate biomass will be estimated by weighing sub-samples and scaling up. Samples will be collected on three or four occasions in spring and summer in each crop, depending on crop growth stage and harvest time.
Carabid beetles and ground-dwelling arthropods
Carabid beetles are an important component in agricultural ecosystems. Their value in ecological studies and as indicators in assessing environmental changes, especially in agricultural ecosystems, has been well documented and is currently an important component in the UK Environmental Change Network Programme. Their value as a food source, especially for farmland birds, has been studied by both the BTO and RSPB.
The aim of this protocol is to assess the effects of GM crops and their management on numbers and species diversity of carabid beetles. Assessment will be made by trapping beetles using standard pitfall traps set at predetermined points along transects within the crop. These same transects will be used to assess vegetation within the crop, the vegetation providing valuable cover and food for carabids. Counts of individuals and their identification to species level will be made. Two other groups important as bird food items will be counted, namely spiders (Aranae) and weevils (Curculionidae).
Bees and butterflies
Butterflies and bees are valued biodiversity components of agricultural ecosystems and they are sensitive to the weed flora of crops and field margins. Bees and butterflies are of conservation importance but also, through pollination, they play an essential role in the maintenance of plant biodiversity. The abundance and diversity of butterflies and foraging bees were scored using the standard method of "transect" walks along the field margins and in the crops themselves, to test for differences between treatments. However, a transect walk in the tall maize crop (up to 3 m) proved impossible so timed observations over a fixed area will be performed instead.
Earthworms
Earthworms have been widely used as indicators of change in the farm environment where they have a fundamental role in maintaining soil structure and nutrient cycling and an important constituent of vertebrate and invertebrate diets. Hence, they were considered a relevant group to monitor to address the null hypotheses in this project. However, the Steering Committee expressed doubts as to their suitability.
An earthworm protocol was developed and methods were tested across four fields in May 1999. This process highlighted serious problems regarding earthworm sampling within this project. The sampling intensity and timing required to detect changes in earthworm abundance, biomass or diversity is not manageable within this project. There were three main reasons for this:
- Appropriate earthworm sampling would not be possible for monitoring in winter oil seed rape and spring oil seed rape. These crops are either harvested or sown during the earthworms’ inactive period so preventing a complete crop cycle assessment of any impacts.
- The field sampling required to obtain reasonable estimates of earthworm abundance, biomass and diversity (>5 samples at pre-sow and pre-harvest) in maize is extremely resource-intensive for the quality of information that will accrue.
- Changes in earthworm abundance, biomass and diversity are likely to occur over the medium to long term i.e. over a time-scale greater than a single crop cycle. It is recognised that other invertebrate groups e.g. collembola are more likely to show responses within an annual crop cycle. This has been taken on within the arthropod protocol.
We therefore consider that earthworms should be removed from the current project. This does not mean they are unimportant, rather that there are more suitable experimental approaches which would address the issue of whether management of GM-modified herbicide resistant crops affects earthworm diversity and soil functioning in general.
2.7.2 Further work required on field sampling protocols
The protocols have evolved throughout summer 1999, and there remain issues to be resolved before spring 2000. The first is to arrive at optimum sampling intensities. This will be undertaken using 1999 field data, by considering the coefficient of variation for each biodiversity indicator that we have recorded. This has been done for vegetation, confirming the methods in use. Invertebrate protocols will also be considered in this way in the coming months. The second issue is to test the revised protocols whereby many indicators are sampled in close spatial proximity.
2.8 Managing the visits to sites
Managing the whole process of field surveys has proved complex, because of the need to fit in with the needs of the individual farmer (including site security considerations), the timetable of availability of survey staff, and the shifting phenologies of crops, management and species according to weather. We have established protocols for the co-ordination of site visits through the crop co-ordinator and the farmer, and while some changes are required, the essential approach is sound.
Crop co-ordinators are involved with sites from their adoption as a test location. They meet with farmers and liaise on the allocation of GM — non-GM treatment to units. The crop co-ordinators act as the focus for links between farmers and the sampling teams from the consortium, ensuring growers are aware of impending visits. Farmers notify the crop co-ordinators when they intend to spray so that teams visiting the site can be warned and precautions taken as necessary. Crop co-ordinators are responsible for ensuring that all sampling protocols are carried out on the test sites and that all farm management data is collected. Following site visits they collect the data, check and code it before sending it for data entry and archiving.
We still plan to use field teams from local sites to undertake the field work, rather than specialised teams for each protocol (although such teams have been used this summer, for the purposes of protocol development).
The transfer of data from field survey and eventual analysis will be managed via a system of standard data collection forms, security safeguards and data validation checks. The data managers have been involved at all stages of the systems development to ensure that the resulting data set fulfil data integrity and data analysis requirements. The data created from the surveys, along with any supporting data, will be integrated in a central database via the data entry and validation process. The database is implemented from a relational design that specifies rules for referential integrity and types checking. When the design is implemented these rules are embedded into the structure of the database. This means that all data must conform to the validation rules to reside in the database. All analyses that contribute to the final results will only take place using data that have been released from this central, validated database.
2.10 Data analysisThe basic model is one that tests the null hypothesis of no effects of the treatment on each indicator individually. Broadly speaking, the model includes between-farm differences, allows for low counts and incorporates dependence between variance of counts and mean density. It is similar to but more realistic than the model given in the tender document, and has been tested using simulated data as part of the re-assessment of power calculations. We now have a novel method for analysis that should be more efficient than previous techniques. Other methods and analyses will be adopted as the project develops.
2.11 A review of the field studies, April — September 1999
2.11.1 Objectives of summer 1999 work
As already stated, the summer field studies of 1999 were intended to provide information and experience to enable us to develop and test the protocols for the study.
The field studies for maize and spring rape comprised farms growing GM crops and comparable non-GM crops. The sites were selected by SCIMAC, and the allocation of GM crop treatment was in consultation with the farmer.
SPRING OIL SEED RAPE
Wiltshire
This was a paired field site, sown on 4 April 1999. The weed flora was assessed on 7 May only. Shortly after this, the farm’s trustees ordered that the GM field was to be sprayed with a herbicid and the trial ended.Oxfordshire
This split-field site was sown on 29 April 1999. The Liberty herbicide was applied to the GM half (10 ha) of the field about one month after sowing. No pre-emergence herbicide was given to the non-GM half (also 10 ha) at sowing, but herbicide-resistant blackgrass in the conventional crop was treated by two herbicide applications. The site was invaded during a demonstration and received substantive damage (see below). However, the sequence of measurements continued as planned. The GM and non-GM crops had a similar rate of development. At flowering, for instance, the GM was two or three days later than the conventional variety (Hyola 401). Desiccant was applied to the crop in late August and the field was harvested on 2 September, 125 days after sowing.Lincolnshire
This was also a split-field site, sown on 28 April. Again the GM variety (8.2 ha) was slightly later than the conventional (Hyola 401, 9.0 ha). The Liberty herbicide was applied to the GM half of the field six weeks after sowing, later than in Oxfordshire because of unsuitable weather A pre-emergence herbicide was applied to the soil of the non-GM half at sowing; additional local spraying was carried out to remove patches of thistles and grass. The crop was swathed in late August, then harvested on 1 September.FORAGE MAIZE
Hertfordshire
A split field site, sown 12th May 1999. The field is approximately 6.4ha in area, divided equally between GM and conventional Maize. The eastern margin of the field is the river Ver. Because of this, approximately 4 m into the GM crop from this edge could not be sprayed. A broad-spectrum Glyphosate herbicide was applied 11 days prior to sowing. The non-GM crop was sprayed with Atrazine herbicide about one month after sowing, Liberty was applied to the GM half of the field a week later. The crop was harvested on 22nd (GM) and 23rd (non-GM) of September. The field has now been planted with barley.Berkshire
A split field site, sown 10th May 1999. The field is approximately 19.9 ha in area, with approximately 5 ha of GM crop. The non-GM part of the field was treated with Atrazine herbicide in early May prior to weed emergence. The GM crop was sprayed almost a month after sowing and again two weeks later. The crop is due to be harvested in early October and planted with winter wheat.Norfolk
A paired field site, the earliest sown on 7th May 1999. The GM field is 2.8 ha and the conventional is 2.4 ha. Both fields have been reclaimed from gravel pits and covered with topsoil. The non-GM field was sprayed with Atrazine in early June. The GM field was sprayed with a first application of Liberty approximately a week later than the non-GM (a month after sowing), the second application was at the end of June. This site was damaged by protestors on 26th July and received substantial damage (see assessment below). However, sampling from this site continued as planned. The crop is due to be harvested in early October and probably seeded with grass.Lincolnshire
A paired field site, the latest sown on 18th May. This is the largest trial with approximately 9 ha GM and conventional fields. The GM field has a small copse within it. The non-GM field was sprayed with Atrazine herbicide at the end of May, the GM field was sprayed with Liberty a month later. The crop is due to be harvested in early October and planted with wheat.2.11.2 Work undertaken and still outstanding
The field studies themselves have been completed, except for follow-up samples of autumn vegetation. However, there remains work on the sorting and identification of samples, expected to be complete by November. The data from these will be used in three ways:
to test the actual process of management of samples; for example, for some groups, the proposed method of freezing the samples simply does not work;
to help finalise issues of timing of sampling during the season
to undertake analyses of coefficients of variation to provide data on sample intensity
to rehearse the process of data management and the construction of the project database
2.11.3 The effects of site loss and damage
The field studies have been conducted under the glare of publicity, and have suffered from site loss and damage.
The only site that was actually lost was near Swindon, where a paired field trial was withdrawn because of concerns over the organic status of the farm. The Oxfordshire site suffered from several unauthorised incursions, not least from the media and from the National Pollen Research Unit at University College Worcester. Actual damage occurred at two sites, at a split-field spring rape farm in Oxford, and a paired maize site in Norfolk. In both cases, the damage was extensive, but monitoring continued on undamaged areas. There was also damage to a field in Lincoln, but the demonstrators damaged a field that was not part of the experiment.
The effects on the science undertaken this summer appear to have been minimal, not least because data collected this summer are essentially for protocol development. In neither case was damage so extensive that monitoring had to stop. However, it should be noted that the damage to the spring rape site has resulted in a much larger population of volunteers than would have been expected, changing the post-harvest management regime.
The summer has raised issues of the security of sites, farmers and the staff. Site security is not the responsibility of the science team, but we are clearly concerned with the loss of valuable data and effort. We are more concerned at the effects on farmers, who are putting a great deal of time and effort into the research programme for what must seem little reward. Indeed, the most likely damaging effect of this summer’s protests is to reduce the number of farmers willing to take part in the study. Opinion within the consortium is split on the issue of secrecy vs openness of the sites.
2.11.4 The winter oil seed rape plantings, 1999-2000
The next phase of the field survey is a pilot study of winter oil seed rape. The emphasis of this study is on finalising field protocols (notably those that have evolved during the summer) and on the timing of surveys in the winter crop. Three sites were selected and seed bank sampling took place at all of these before the crop was sown.
2.12 Overall recommendations for autumn / winter 1999 — 2000
The focus of the work of the project for the next few months is to complete the development of protocols and systems that will be put into practice next spring.
Planning for the spring 2000 field work is already starting; for this to take place efficiently, it is imperative that we are provided with the list of possible sites to choose from as soon as possible.
Published 23 December 1999
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