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Providing evidence to improve practice

Individual study: Hedgerows managed within organic farmland had greater plant species diversity than conventional hedgerows in Denmark

Published source details

Aude E., Tybirk K., Michelsen A., Ejrnaes R., Hald A.B. & Mark S. (2004) Conservation value of the herbaceous vegetation in hedgerows - does organic farming make a difference? Biological Conservation, 118, 467-478

Summary

Organic farming, which primarily aims to avoid the use of pesticides and artificial fertilisers, is one method by which it may be possible to reduce the effects of intensive farming on the environment. This study investigated plant diversity along the bottoms of comparable hedgerow within organic and conventional farming systems in Denmark.

Twenty eight hedgerows on 15 organic farms and 28 conventional hedges on 19 conventional farms (in the same district) were sampled across Denmark. All hedgerows had been established 6-22 years ago by the same company. Organic farms had been state

certified for the lifetime of the hedgerow or a minimum of 10 years and so no artificial fertilisers or pesticides were allowed. Fields adjacent to hedges had been managed organically or conventionally since hedgerow establishment; no headlands or unsprayed field margins were present.

Plant species and abundance were sampled in three plots (0.5x20 m; 20m apart) along the hedgerow, 0.2 m from the field and in grass leys 0.2 m from the fence in August 2001 or 2002.

 

In total 153 vascular and 16 bryophyte species were recorded in the hedge bottoms.

Numbers of hedge bottom plant species were significantly higher in organic (162 species, 34 species/100 m of hedge) than in conventional hedgerows (115, 24/100 m). The difference in species richness was largely due to higher numbers of weedy species, semi-natural species, and bryophytes in organic hedgerows. Two uncommon species were recorded in organic hedgerows: one protected orchid Epipactis helleborine and a relatively rare species Hypericum humifusum.

Note: If using or referring to this published study, please read and quote the original paper, this can be viewed at: doi:10.1016/j.biocon.2003.09.022