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Biodiversity; Some findings
Plants: five times as many wild plants in organic arable fields, 57% more species and several rare and endangered wild arable species found only on organic farms.
Birds: 25% more birds on the organic field edge, 44% more in-field autumn/winter; 2.2 times as many breeding skylarks and higher skylark breeding rate. (Skylark numbers have dropped from 3.8m pairs in 1972 to 1.5m in 1996 - the greatest decline in absolute numbers of any farmland bird).
Invertebrates: On organic farms, 1.6 times as many of the arthropods that comprise bird food; three times as many non-pest butterflies in the crop areas; up to five times as many spider numbers and up to twice as many spider species.
Crop Pests: significant decrease in aphid numbers on organic land; no change in pest butterfly numbers.
Habitat Quality: organic field boundaries had more trees, larger hedges and no spray drift; the crops were sparser, with no synthetic chemicals, allowing more weeds; more grassland and a greater variety of crop types.
More Biodiversity Beneficial Practices on Organic Farms: crop rotations with grass leys, mixed spring and autumn sowing, more permanent pasture, use of green manures and avoidance of agro-chemicals.
See 'Biodiversity'; 'Biodiversity, some of the figures relating to the UK'; For more information: www.soilassociation.org