SLU news

More pollinators on organic farms

Published: 08 October 2012

Studied organic farms had more pollinators, both more species and higher densities. However, the number of species was not larger at older organic farms than at more recently converted, suggesting that the positive effects of conversion to organic production comes quickly.

On October 12, Georg Andersson will defend, his thesis " Effects of farming practices on pollinators and pollination across space and time" at the Centre for Environment and Climate Research, Lund University.

Pollination and pollinators
Georg's thesis deals with how the time span after conversion to organic production affects biodiversity and ecosystem services in the form of pollinators and pollination. Georg has also studied how the landscape influences the presence of pollinators and the services they perform.

Organic and heterogeneous farms had more species
There were more species and higher densities of pollinators on organic farms and in heterogeneous landscapes; landscapes consisting of a mosaic of forest, grassland and arable land. In contrast, the number of species was no greater on older organic farms than on newly converted, suggesting that the positive effects of organic production comes quickly. As for the number of individuals, both hoverflies and butterflies increased in numbers with time since conversion, which supports the results presented in a news 2012-10-05.

Efficient pollination in organic cereal fields
In an attempt to measure pollination, strawberry plants were placed along the edge of the grain fields. Those strawberry plants were better pollinated on organic farms. The reason was that those farms have a higher species richness and diversity of pollinators, which is important for a full pollination of strawberries (see news 2012-03-02). Field beans had more of fully developed pods at organic farms. Also the heterogeneity of the surrounding landscape affected the pod development.