A new report written by staff from English Nature and the Royal Society for the Protection of Birds reviewed 76 studies and found that there is more wildlife on organic farms than on conventional farms.

A new report written by staff from English Nature and the Royal Society for the Protection of Birds reviewed 76 studies and found that there is more wildlife on organic farms than on conventional farms.

The report stresses that “the intensification and expansion of modern agriculture is amongst the greatest current threats to worldwide biodiversity. Over the last quarter of the twentieth century, dramatic declines in both range and abundance of many species associated with farmland have been reported in Europe… During the next 50 years, global agricultural expansion threatens to impact worldwide biodiversity on an unprecedented scale that may rival climate change in its significance”.

The report found that:

• There are more birds, butterflies, beetles, bats and wild flowers on organic farms than conventional farms.
• Many of these differences apply to species known to have experienced declines in range or abundance as a consequence of agricultural intensification, a significant number of which are now the subject of direct conservation action (e.g. skylark, lapwing, greater and lesser horseshoe bat, corn buttercup).
• Organic management provides a clear advantage over agri-environment schemes because the farm as a whole is subject to organic standards, rather than limited areas under these schemes.
• Organic farming could play a significant role in increasing wildlife across lowland farmland in Europe.

Peter Melchett, the Soil Associations Policy Director said: "The scientific case for the wildlife benefits of organic farming is now settled and beyond doubt. People feel powerless in the face of environmental disasters like the loss of wildlife from the British countryside over the last thirty years. Everyone assumes that reversing such destruction will be painful and unpleasant. Not any more. Anyone can enjoy fresh, tasty organic food from Britain, knowing that they are also helping British birds, bees, bats, beetles and butterflies.

“The results confirm what organic farmers have seen on their farms for decades: conversion to organic means more wildlife, a greater variety of wildlife, and more of the wildlife species that have declined on non-organic farms over the last 50 years. The results fully justify the Governments decision to pay organic farmers twice as much as non-organic farmers under the new agri-environment schemes to be launched next year.”

The Soil Association welcomes the publication of this review, which confirms the findings of a Soil Association report published in May 2000 (The Biodiversity Benefits of Organic Farming). The Soil Association report reviewed all the known studies that compared the levels of wildlife on organic and conventional farms and found that overall organic farms support substantially higher levels of wildlife in lowland areas, particularly of those wildlife groups which are declining.

Key extracts from the EN/RSPB report (Soil Association emphasis):

p4 "During the next 50 years, global agricultural expansion threatens to impact worldwide biodiversity on an unprecedented scale that may rival climate change in its significance for the persistence of a panoply of species … A wealth of evidence now points to agricultural intensification as the principal cause of the widespread declines in European farmland bird populations..."

p7 With the exception of one piece of research "all of the studies investigating the flora of arable and mixed farming systems recorded higher weed abundance and species richness in fields under organic management, regardless of the arable crop being grown (e.g. mean number of weed species in both margins and cereal fields was more than twice as high under organic management ... In several studies, fields under organic management held considerably more rare and/or declining species ... " including including red hemp-nettle, corn spurrey, cornflower and corn buttercup.

p11 "Evidence from comparative studies under arable regimes indicated a general trend for higher earthworm abundance under organic management." One study "reported higher earthworm abundance (almost twice the density) and species diversity, both in-field and within grass margins, in organic than conventional fields."

p13 One study "recorded a significantly higher total abundance of butterflies on organic than conventional farms, in both crop-edges and field boundaries and in both years of the study - a direct result of a greater abundance of non-pest species on organic farms (up to twice the mean density found on conventional farms). In contrast, the two major pest species (large white Pieris brassicae and small white P. rapae) showed no significant difference in abundance between systems."

pp14/15 "Beetle communities are the most commonly studied animal group in comparisons of farming systems. Eleven studies have focussed on beetle populations, with a further ten recording abundance and species richness as part of wider studies, all but two in arable habitats. Twelve studies reported a generally higher abundance, and some evidence for greater species richness, of carabids [beetles] on organically managed fields ..... with four studies indicating the reverse."

p18 One study "investigated bat activity and species richness using a paired farm (organic/conventional) design. Both total bat activity (all species) and foraging activity were significantly higher on organic farms (by 61% and 84% respectively), suggesting that bats were actively selecting organically managed habitats ..".

p19 "Five major studies have compared bird communities as a whole on organic and conventional farmland. All five assessed bird abundance and/or species richness, primarily during the summer, with one also examining nest density and nesting success. All five studies reported greater avian [bird] abundance and/or species richness on organic than conventional farms, although there was some inter-study variation .... Consistencies between the two European studies included higher densities of skylark, blackbird and greenfinch on organic sites" and another study "found 31 species to be significantly more abundant on organic than conventional farms, with only three showing the opposite trend. Of those species showing greater abundance on organic farms, many had declined nationally over the previous two decades (e.g. lapwing, linnet, corn bunting)."

p20 In one study "Skylark territory density was generally found to be greater in organic rather than conventional fields (more than double within cereal fields), with some evidence that nesting success was also greater in organic fields".

p25 The majority of the 76 studies reviewed in this paper clearly demonstrate that species abundance and/or richness, across a wide-range of taxa, tend to be higher on organic farms than on locally representative conventional farms (Table 1). Of particular importance from a conservation perspective is that many of these differences apply to species known to have experienced declines in range and/or abundance as a consequence of past agricultural intensification, a significant number of which are now the subject of direct conservation legislation (e.g. skylark, lapwing, greater and lesser horseshoe bat, corn buttercup Ranunculus arvensis and red hemp-nettle are all UK government Biodiversity Action Plan species). These biodiversity benefits are likely to derive from the specific management practices employed within organic systems (Appendix 1), which are either absent or only rarely utilized in the majority of conventional systems

p27 ... this review indicates that the biodiversity benefits of organic management are likely to accrue through the provision of a greater quantity/quality of both crop and non-crop habitat than on conventional farms.

p28 In the UK, agri-environment schemes (AESs) such as Environmentally Sensitive Areas (ESAs), the Countryside Stewardship Scheme (CSS) and the Rural Stewardship Scheme (RSS) (in England and Scotland) and ‘Tir Gofal (in Wales) seek to provide financial incentives to (primarily conventional) farmers to undertake management practices falling broadly into the three categories outlined above (e.g. Ovenden et al., 1998; Vickery et al., 2004). These schemes have proved successful, at least where management options are ecologically and geographically well targeted (e.g. Peach et al., 2001; Swash et al., 2000). However, organic management currently provides a clear advantage over such schemes in that the farm as a whole is subject to the organic standards, rather than the limited areas on a conventional farm that may be exposed to environmental management under AESs.

p29 ... the available evidence indicates that organic farming could play a significant role in increasing biodiversity across lowland farmland in Europe.