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Estimating wildlife exposure to pesticides in crops: additional scenarios and data - PS2328

Description
Judgements about the safety of pesticides to wildlife begin by comparing the toxicity of the pesticide and the likely exposure of wildlife to that pesticide. Much is known about pesticide toxicity; rather less about wildlife exposure. Defra’s Pesticide Safety Directorate (PSD) assumes a “worst case”: that birds and mammals at risk feed exclusively among treated crops and that all the food they find there is contaminated with a pesticide. Detailed measurements of how wildlife uses farmland are needed either to support these conservative assumptions or to replace them with more realistic estimates.

Project PN0915 began this work by identifying which wildlife species depend on which key crops, and, using VHF telemetry, measuring the amount of time some key species (seed-eating birds, insectivorous birds, small mammals) spend in agricultural habitats and thus estimating their likely exposure to pesticides there.

Project PS2310 continued this work by estimating time in agricultural habitats for further key groups of grazing mammals and birds, using newly available satellite tracking technology as well as existing VHF telemetry.

This further project will continue in this vein, providing further information on use of crops by wildlife where, at present, information is scant or non-existent (requiring risk assessors to make assumptions). This will include extensive surveys to examine use of minor arable crops (pulses, vegetables, maize etc.) and newly-drilled crops by birds, and use of orchards by grazing small mammals. VHF telemetry will be used to collect additional data on use of crops by woodmice. Work to examine use of crops by grazing birds, using satellite telemetry, will continue, making best use of satellite tags already deployed.

The results will directly benefit PSD in their daily work of assessing pesticide risks in that they will have further and better estimates of exposure to pesticides for wildlife based on evidence gathered in the field.
Objective
The objective of this project is to provide further information on use of crops by wildlife where, at present, information is scant or non-existent (requiring risk assessors to make assumptions).

We have a list of specific crop/species scenarios for which field data is lacking, and we aim to address these individually as set out below.

The results will directly benefit PSD in their daily work of assessing pesticide risks in that they will have further and better estimates of exposure to pesticides for wildlife based on evidence gathered in the field.
Technical and Scientific Aims/Objectives
1. Conduct a literature review of use of orchards by small mammals. This will inform risk assessments for products intended for use in orchard crops, and indicate whether it is appropriate to conduct fieldwork quantifying use of orchards by small mammals further. To be completed May 2006.

2. Conduct survey work to measure prevalence and abundance of small mammal species in orchards. This will only be done if the results of Objective 1 indicate that it is appropriate. If not, resources will be diverted to other parts of the project. To be completed by November 2006.

3. Conduct survey work to measure prevalence and abundance of birds using newly-drilled crop fields. This will inform risk assessment for products formulated as seed treatments, and may identify associations between particular bird species and particular crops. Seed treatments are of particular concern since the active ingredient is directly associated with food items and must necessarily be applied at a high concentration. To be completed by July 2008.

4. Conduct survey work to measure prevalence and abundance of birds using minor arable crop fields. A survey of birds using major arable crops (oilseed rape, sugar beet, winter barley and winter wheat) was carried out as part of Project PN0915, and has proved useful in indicating for which species risk assessments should be carried out, and for which species further field data is required. These four crops, however, represent only about 73% of UK arable cropland (Garthwaite et al 2005 – PUS Report 202, Defra Publications, London)-; data on use of the remaining 27% is scant. This work will make further data available. To be completed by January 2008.

5. Collect radio-tracking data quantifying use of arable crops by woodmice. Data indicating likely exposure of woodmice to pesticides used in cereals in winter and in potatoes in summer was collected as part of Project PN0915. Further data covering other summer crops (e.g. sugar beet, oilseed rape, maize) and cereals at other times of year, particularly spring and autumn drilling seasons, is now required. To be completed by March 2008.

6. Collect satellite telemetry data quantifying use of arable crops by large grazing birds. This work was begun as part of Project PS2310, and a number of wild greylag geese are now wearing satellite radio tags. Because data can be collected largely automatically, the effort required to continue collecting this data for the remaining lifetime of the radio tags is relatively small, while the value of the data is high. For this reason, we propose to continue collecting this data. To be completed by December 2007.

7. Collect field data on use of arable crops by insectivorous mammals. Common and pygmy shrews are the insectivorous mammals most at risk from arable insecticides due to their small size and consequent high demand for energy. It was established in Project PS2310 that radio-tracking shrews was not practicable, and that other methods would have only limited ability to measure the time spent among crops. However, an intensive trapping experiment might indicate whether this approach could effectively provide estimates of crop usage. During 2004 and 2005, populations of shrews in the UK appeared to be too small to make this experiment worthwhile. Preliminary trapping to find out if populations have increased could be followed by intensive trapping during the summer of 2006 or 2007. To be completed by November 2007.

Project Documents
• Final Report - SID5A : Estimating wildlife exposure to pesticides in crops: additional scenarios and data - SID5   (12624k)
Time-Scale and Cost
From: 2006

To: 2009

Cost: £731,802
Contractor / Funded Organisations
Central Science Laboratory
Keywords
Animals              
Arable              
Birds              
Crops              
Environmental Effects              
Environmental Impact              
Farming              
Habitats              
Mammals              
Monitoring and evaluation              
Pest and Weed Control              
Pesticide use              
Pesticides              
Plants and Animals              
Wildlife              
Fields of Study
Pesticide Safety