Biodiversity on Organic Farms: Recent Comparative Research in Europe
The Study	Study Area	Key Findings	Discussion	Reference
Butterflies UK study by the Oxford University Wildlife Conservation REsearch Unit and funded by Butterfly Conservation and the SAFE Alliance.	A survey in 1994 of 8 paired farms (organic and conventional) comparing butterfly populations in similar habitats. Study expanded in 1995.	Mean abundance of 23 non-pest butterfly species was 23.1/Km on organic farms compared to 11.8/Km on conventional farms.	Butterflies benefitted on organic farms due to the absence of herbicide to base of hedges, different cropping patterns and better hedgerow management.	Warren, Martin (1996); New Study Shows Organic Farms are Better for Butterflies - Press Release; The British Butterfly Conservation Society, Essex UK.
Birds UK study carried out by the British Trust for Ornithology (BTO) and funded by the Ministry of Agriculture, Fisheries and Food and WWF-UK	Study of 22 paired farms (organic and conventional) from 1992-1994 of bird densities in the breeding and wintering season, plus a study of skylarks and survey of food sources.	Bird density of all bird species were higher on organic farms during both seasons. Skylark populations were twice as high on organic farms. Invertibrate and plant food sources were also higher.	BTO identified differences on organic farms due to hedgerow structure, cropping patterns and type and increased amount of food sources.	Chamberlain, D, Fuller, R and Brooks, D (1996);The Effects of Organic farming on Birds; EFRC Bulletin 21, Jan. 1996;EFRC, Newbury UK
Plant Species German study carried out by the institute for Organic Agriculture at the University of Bonn.	Weed species diversity was compared on arable farm pairs in 1994 and 1995. Comparisons were made from 32 organic and 36 conventional sites.	Weed species were twice as high, and endangered species were only present on organic farms. Average plant species on permanent pastures were 12.9 (+/- 2.85) on organic farms and only 7.1 (+/- 1.93) on conventional sown pasture.	Non-use of herbicide was identified as the main factor for increased species numbers, along with reduced soil cultivation. Field boundaries were also identified as refuge sites for endangered weed species, as well as birds and arthopods.	Frieben, B and U Kopke (1995); Effects of farming systems on biodiversity; in Isart J and Llerena, JJ (eds); Biodiversity and Landuse: The Rols of Organic Farming; Proceedings of the first ENOF Workshop, Bonn.
Soil Biota Swiss study carried out by the REsearch Institute of Organic Agriculture (FiBL). Oberwil.	Comparison, between 1990 and 1995, of microbial and faunal diversity on a long-term field trial comparing biodynamic, organic, two conventional and a control plots.	Microbial biomass and activity and earthworm and carabid species were highest in the biodynamic plots. Density of epigeal aethropods were 93% and 88% higher respectively in the biodynamic and organic plots.