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Biodiversity and associated ecosystem services in small vs. large scale agriculture

Applicant Professor Dr. Teja Tscharntke, since 9/2018
Subject Area Ecology of Land Use
Term from 2016 to 2019
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 312807292
 
Final Report Year 2020

Final Report Abstract

In the first part of this project, we studied farmland biodiversity and farmers’ profit along the former Iron Curtain between East and West Germany. Both biodiversity and profit can be strongly shaped by local and landscape level agricultural intensification, but the role of legacy effects and detailed quantification of ecological–economic trade-offs are largely unknown. In Europe during the 1950s, the Eastern communist bloc switched to large-scale farming by forced collectivization of small farms, while the West kept small-scale private farming. We show that large-scale agriculture in East Germany reduced biodiversity, which has been maintained in West Germany due to > 70% longer field edges than those in the East. In contrast, profit per farmland area in the East was 50% higher than that in the West, despite similar yield levels. In both regions, switching from conventional to organic farming increased biodiversity and halved yield levels, but doubled farmers’ profits. In conclusion, European Union policy should acknowledge the surprisingly high biodiversity benefits of small-scale agriculture, which are on a par with conversion to organic agriculture. In the second part of this project, we tested the ecological and economic effectiveness of the two most popular agri-environment schemes in Lower Saxony, Germany: wildflower strips next to winter wheat fields as off-field practice and organic farming on winter wheat fields as on-field practice. We found that plants benefitted most from organic farming, whereas flowering strips had only a positive effect on plant richness in field margins, but no effect in the fields compared to the control. Due to the high flower cover, flower strips supported three times more bee species and about 25% more hoverfly species than organic farming, with both AES being more effective than the control. Finally, both AES supported equally well carabids and spiders with about 20-30% higher species numbers than the control, with exception of rove beetles, which rather avoided fields with flower strips (in contrast to control and organic fields). Field size showed only a slight negative trend on the biodiversity of the studied taxa, probably owing to the relatively short gradient in the small-scale agroecosystem of the study area. Economic analyses showed the highest costs in conventional fields (the control) and the highest revenues in organic fields, leading to more than two times higher profit, whereas fields with flower strips exhibited a bit lower profit than the control. Wheat yield in both types of conventional fields was about 90% higher than in organic fields. In summary, both agri-environment schemes support farmland biodiversity depending on the taxonomic group. The results received a lot of media attention.

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