Long-term research has shown that agri-environment programs can dramatically boost regional bird and butterfly populations without affecting food output.
At Hillesden, a 1,000-hectare commercial arable farm in Buckinghamshire, scientists from the UK Centre for Ecology & Hydrology (UKCEH) spent a decade carefully observing the effects of a large-scale experiment funded by Defra.
Beginning in 2005, this involves establishing a number of natural habitats, including tussocky grass borders to sustain a variety of birds, insects, and small mammals, wildflowers for pollinators, and seed-bearing plants for birds.
The experiment evaluated how well these agricultural environmental solutions reduced biodiversity losses brought on by the development of UK farming methods since the Second World War, including a reduction in species vital to agricultural output like pollinators and crop insect predators.
The majority of species had higher populations at Hillesden than in other comparable farmed landscapes without agri-environment measures throughout the same timeframes, according to the longest-running monitoring study of its kind.
Between 2006 and 2016, the populations of all bird species increased by a third, compared to an average rise of just under 13% at other monitored sites, while the populations of all butterflies increased by 40% between 2009 and 2017, compared to an average increase of 21% elsewhere.
In spite of the loss of agricultural land for habitat creation, a prior UKCEH analysis of six years’ worth of harvesting data indicated overall yields at Hillesden were preserved and improved for some crops.
At Hillesden, the common linnet population more than doubled, while the yellowhammer and chaffinch also performed better there than at other locations for seed-eating birds. Meanwhile, birds that typically consume insects, such the great tit (up 88%) and blue tit (up 8%), benefited from the protection afforded by hedges and grass margins (up 73 percent).
The gatekeeper butterfly, which feeds on grasses, and the green-veined white butterfly, which eats wildflowers in field edges, did exceptionally well at Hillesden during the study period. The numbers of both species doubled over the period studied.
Investigating changes in populations over a significant period of time, and comparing these with other sites, means we can be confident that agri-environment options can bring long-term term benefits for bird and butterfly populations. Hillesden is a typical, large arable farm with conventional agricultural practices, in an ordinary landscape with no large patches of natural habitat. Therefore, it is likely that the results of our long-term study indicate what can be achieved on other commercial farms with good planning, implementation, and management of agri-environment measures.
Dr. John Redhead
It has been challenging to demonstrate that the increases are not simply the result of many people moving into the local area or only serving as a temporary boost to populations, despite previous scientific studies showing that bird and butterfly numbers are higher where agri-environment options are present.
Dr. John Redhead of UKCEH, lead author of the new research paper, published in the Journal of Applied Ecology, explains:
“Investigating changes in populations over a significant period of time, and comparing these with other sites, means we can be confident that agri-environment options can bring long-term term benefits for bird and butterfly populations.”
“Hillesden is a typical, large arable farm with conventional agricultural practices, in an ordinary landscape with no large patches of natural habitat. Therefore, it is likely that the results of our long-term study indicate what can be achieved on other commercial farms with good planning, implementation, and management of agri-environment measures.”
The British Trust for Ornithology (BTO) and Butterfly Conservation submitted data from other farmed landscapes for comparison, and UKCEH and the Wildlife Farming Company studied the changes in bird and butterfly populations at Hillesden as a result.
The Hillesden experiment involved removing tracts of land from food production that were either unproductive or difficult to farm. The new habitats encouraged more pollination and natural pest management, which enhanced crop productivity in those areas of the farm.
Marek Nowakowski of the Wildlife Farming Company says: “The Hillesden study shows that it is possible to balance wildlife conservation with efficient food production. I am confident other farmers could achieve similar results with the right training and advice.”
Twelve common bird species and nine different butterfly species had their numbers observed by the researchers. The small white butterfly, a nuisance species that mostly feed on farmed brassicas like oilseed rape, was the only species that performed noticeably worse at Hillesden compared to other sites.
According to the study’s authors, as a result of an increase in beneficial species, reductions may be brought on by predation or competition. The experiment’s wildlife habitats were preserved by Hillesden and included in a Countryside Stewardship Scheme.
Additionally, it is one of the farms that UKCEH is working with to test out in-field strips to see how these habitats could increase populations of pest-controlling insects and lessen the need for pesticides.
Robin Faccenda, the owner of the Hillesden estate, says: “In these challenging times the need to balance profitable farming with increased wildlife delivery has never been more important. My advice to anyone wishing to improve the wildlife on their farm would be to get good advice and create a range of appropriate quality habitats.”
