Conservation through wise use
NEWS RELEASE
SUPPLEMENTARY NOTES ON THE REPORT
"Indirect Effects of Pesticides on Birds"
The Indirect Effects of Pesticides on Birds report has been produced for the Joint Nature Conservation Committee by English Nature and the Royal Society for the Protection of Birds. It summaries the findings of a major review by conservation organisations including The Game Conservancy Trust and puts forward recommendations for future actions.
The weight of evidence suggests that the indirect effect of using some pesticides on farmland may be a key factor in the decline of 11 bird species including the skylark, lapwing and blackbird (contact RSPB for details).
Only in the case of one species, the grey partridge, is the scientific community sure that
pesticide use is resulting in population declines. This independent research work has
been carried out by The Game Conservancy Trust, funded principally by donations from
its 26,000 members.
The grey partridge is found predominantly on lowland arable landscapes, particularly cereal fields. Work by The Game Conservancy Trust has shown that some pesticides can reduce the amount of food available for partridge chicks sufficiently to affect survival and therefore breeding success, resulting in population declines. As far back as 1968, the Trust began, with the co-operation of farmers, to investigate the link between agricultural husbandry and grey partridge numbers at its study area on the South Downs in Sussex. Trust scientists have continued to monitor insect abundance in Sussex ever since. This information has provided a unique insight into how changes in agriculture have reduced farmland wildlife. The study has also become the longest and most comprehensive indicator of farmland biodiversity in the world.
Grey partridge chicks require insects (a rich protein source) for the first 21 days of life. They favour beetles, caterpillars, plant bugs and plant hoppers. However these insects have their own specific requirements and depend in turn on broad-leaved weeds.
Pesticides - a catch all term including both herbicides and insecticides - can disrupt the food chain on which grey partridge chicks rely. This can happen in two ways. First, herbicides can kill the essential cereal weeds thereby indirectly reducing insect numbers. Second, insecticide applications can kill the chick food insects directly. The net result is a diminution in the supply of insect food for grey partridge chicks.
The relative impact of herbicides and insecticides has shifted with time. In the 1960s the use of herbicides was most damaging. By the late 1980s the growing use of insecticides had meant this group of chemicals was also crucially important in harming insect abundance.
The Game Conservancy Trust has focused on producing workable solutions to these problems. Its research identified that insects numbers tended to be highest at the field edges. This was also where grey partridge chicks fed most. The Trust combined both elements and devised the Conservation Headland.
The Conservation Headland is a narrow - six metre - selectively sprayed strip at the crop
edge. This allows important broad-leaved weed species to flourish and hence encourages
the insects which live on them. These insects are vital food items for grey partridge
chicks and other birds.
Studies have shown that Conservation Headlands are capable of restoring levels of grey
partridge chick survival to those recorded on farms prior to the widespread use of
pesticides. The added incentive for farmers is that profits can be maintained as a field
headland is often the lowest yielding area within a field.
While grey partridge numbers are declining nationally many farms and estates which have adopted Conservation Headlands enjoy stable grey partridge populations.
The Trust has also pioneered Beetle Banks as a means of reducing pesticide inputs and encouraging food insects useful to grey partridge chicks. Beetle Banks are ploughed ridges which when sown with tussocky grass species and colonised by broad-leaved weeds provide a home to predatory insects such as ground beetles, rove beetles and spiders. These move out into the crop and devour arable pests such as aphids. It is a form of biological control and allows farmers to reduce their pesticide inputs without sacrificing crop yields.
Dr Nick Sotherton, the Director for Farmland Research at The Game Conservancy Trust, said:
"Our work on pesticides and their impact on the grey partridge’s food chain has allowed the Trust to pioneer techniques such as Conservation Headlands and Beetle Banks which allow the maximum conservation returns with minimal disruption of the
farming system. While there is not a moment to lose in aiding our threatened farmland species, not all pesticides are harmful."
Dr Sotherton added:
"The solution is not in abandoning pesticide use even if that were at all feasible.
Rather it is modifying their use to avoid specific threats and in encouraging a shift in
the support structure to favour the adoption of more environmentally rewarding but
practicable farming methods. That is the real challenge."
Notes to Editors
The Game Conservancy Trust is a registered charity conducting research into gamebirds, the
ecology of their habitats and other species such as insects and wildflowers also using these
habitats. The Trust employs almost 50 scientists at sites throughout Britain.
Under the Government’s UK Biodiversity Action Plans, The Game Conservancy Trust has been
appointed the lead organisation to co-ordinate the national conservation strategy for the grey
partridge.
SPECIAL THANKS TO THE GAME CONSERVANCY TRUST, CONTACT DETAILS BELOW:
For more information on these supplementary notes telephone our Press Department on 01425 652381. Fax: 01425 651026.