One day after researchers from Wales, who contributed findings to an international study comparing the effects of organic and conventional farming on biodiversity, said they did not find significantly more indicator species on organically managed sites, compared to conventional farms, a German team has offered more insight.

Commenting on their part in the major comparative study, published on Tuesday, researchers from Aberystwyth University noted that organic farms tended to have a higher species richness (more plant and animal groups), but said that the presence of more different habitats on farms seemed to have a greater effect on encouraging biodiversity.

However, whilst they agreed that the number of habitats on the land plays an important role in supporting a diverse array of life on farms, German researchers who contributed to the same study found that certain organic farms do tend to support biodiversity. They noted that the type and intensity of farming practices seemed to be key elements in determining biodiversity, and that in direct comparisons organic arable farms had performed better.

Whereas the Welsh study looked at low-to-mid intensity uplands farms, researchers from Munich looked at dairy farms over a three year period. TUM's Prof. Kurt-Jürgen Hülsbergen commented, "Organic farming is beneficial to the richness of plant and bee species. However, observed benefits concentrate on arable fields."

The researchers from Technische Universität München (TUM) acknowledged that, once figures from all ten participating countries were factored in, "The study shows that even organic farms have to actively support biodiversity by, for example, conserving different habitats on their holdings."

More species were found in organic arable fields than in non-organic fields. In contrast, there was little difference in grasslands or vineyards. Organic farming benefited the four indicator groups of plants, earthworms, spiders and bees in different ways. In general, more species of plants and bees were found on organic than on non-organic fields, but not more species of spiders and earthworms.

TUM researcher Max Kainz qualified the TUM team's claims, "Most species found in fields on organic farms tend to be concentrated in boundary areas on non-organic farms. There was little difference in the total number of species on the farms."

To sustain farmland biodiversity, which is currently under grave threat, researchers said there is a pressing need to increase the number of habitats on farms. They recmomended adding structural elements, such as woods, grass verges and fallow land, to benefit a range of species and retur a measure of balance to agro-ecosystems.

"Surprisingly, viewed across all regions, we did not find a higher number of natural habitats on organic farms than non-organic farms," Kainz said, echoing his Welsh counterparts.

Prof. Hülsbergen added, "It was clear that habitat diversity is the key to species diversity. The results of the study underline the importance of maintaining and expanding natural landscape features – something that the EU's Greening Program has been trying to accomplish."

If additional habitats, different to the rest of the farm, for example hedges in grassland farms or herbaceous strips in arable farms, are encouraged they can have a huge impact on a farm's biodiversity, Hülsbergen said.