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Institute of

OF Organic Farming

Monitoring of biodiversity in Trenthorst


Monitring of natural biodiversity on the experimental station in Trenthorst estates since conversion to organic farming

© Thünen-Institut/OL

Development of the natural biodiversity on the experimental station of the Trenthorst estates since conversion towards organic farming in 2001

The protection and development of the natural biodiversity is one of the principle goals of organic farming. The development of organic agriculture must consider these goals. 

Background and Objective

The research focus on system comparison at the location of the estate Trenthorst in Schleswig-Holstein (Germany): organic versus conventional as well as different types of organic: with and without livestock or low or high intensity of production. The research does assess the impact of the farming system development on natural biodiversity. 


After conversion towards organic farming in 2001 the entire estate of 600 ha (340 arable land, 130 ha permanent grassland, 80 ha forest, 50 ha miscellaneous) was assessed to check the status of the biodiversity. Main species groups as segetal and grassland flora, ground beetles, ground spiders, birds, hares, deers (farm land species), earth worms, collembolae (soil species) as well as zoobentos, amphibia (water species) are monitored in non-regular periods and the impact of the farming system developement assessed.  

Our Research Questions

In the last years the number of studies concerning organic farming and biodiversity has expanded significantly. A total of 343 papers with 396 citations (83 %) came to the conclusion, that organic farming shows for more biodiversity compared with conventional farming. 

Nevertheless, it was not clear from these studies, what are the reasons and what will happen in the case of changing the organic system (more intensive, changing crop rotation and management system, more or less livestock)?

How does develop the segetal and grassland flora?

  • How does develop the bird population?
  • How does develop the hare and deer population?
  • How does develop the ground beetle and ground spider population?
  • How does develop the earth worm and collembola population?

Preliminary Results


  • The segetal flora has changed significantly in the first years after conversion. Most of them were weeds. After 6 years a climax level has been reached. One of the reasons was the improved weed management skills of the farm staff. 
  • Rare wild plants have not appeared.
  • Rare and wished plants must be interseeded to have them on the farm land.
  • On grassland only little change on flora could be observed.


  • Sky lark and other farm land related birds have gained significantly. Main reasons are the changes in crop rotation, the reduced crop density and the differences in farm land management. 
  • The survival rate of wild birds is depending on feed in summer and winter.
  • Hares and deers have favoured organic fields in comparison to conventional fields.
  • Ground beetles and ground spiders have reacted rapidly after conversion.
  • Soil fauna like earth worms and colembola have changed significantly. The management of the soil is more important. Ploughing has negative impacts on them. 


Prof. Dr. agr. habil. Gerold Rahmann

+49 160 94945756
+49 4539 8880 200


1.2001 - 12.2025

More Information

Project status: ongoing


  1. 0

    Phillips HRP, Bach EM, Bartz MLC, Bennett J, Beugnon R, Briones MJI, Brown G, Ferlian O, Gongalsky KB, Guerra CA, König-Ries B, Krebs J, Orgiazzi A, Ramirez KS, Russell DJ, Schwarz B, Wall DH, Brose U, Decaëns T, Moos JH, et al (2021) Global data on earthworm abundance, biomass, diversity and corresponding environmental properties. Sci Data 8:136, DOI:10.1038/s41597-021-00912-z

  2. 1

    Moos JH, Schrader S, Paulsen HM (2020) Minor changes in collembolan communities under different organic crop rotations and tillage regimes. Landbauforsch J Sustainable Organic Agric Syst 70(2):113-128, DOI:10.3220/LBF1611932809000

  3. 2

    Moos JH, Paulsen HM, Rahmann G (2013) Monitoring der Deckungsgrade der Segetalflora auf Flächen des ökologischen Landbaus über einen Zeitraum von 10 Jahren. In: Neuhoff D, Stumm C, Ziegler S, Rahmann G, Hamm U, Köpke U (eds) Beiträge zur 12. Wissenschaftstagung Ökologischer Landbau : Ideal und Wirklichkeit: Perspektiven ökologischer Landbewirtschaftung . Berlin: Köster, pp 322-325

  4. 3

    Rahmann G (2011) Biodiversity and organic farming: What do we know? Landbauforsch 61(3):189-208

  5. 4

    Rahmann G (2008) Maintenance of protected biotopes in Germany by goats keeping. In: Proceedings of the 9th International Conference on Goats : "Sustainable Goat Production: Challenges and Opportunities of Small and Large Enterprises" ; Querétaro, México, August 31st - September 4th, 2008. p 100

  6. 5

    Rahmann G, Piper W (2007) Entwicklung der Laufkäferpopulation Carabidae nach fünf Jahres Umstellung eines Großbetriebes auf den Ökologischen Landbau in Norddeutschland. In: Zikeli S, Claupein W, Dabbert S (eds) Beiträge zur 9. Wissenschaftstagung Ökologischer Landbau "Zwischen Tradition und Globalisierung" : Universität Hohenheim, 20.-23. März 2007 ; Bd. 2. Berlin: Köster, pp 867-870

  7. 6

    Rahmann G, Ashworth SW, Boutonnet JP, Brunori G, Papadopollos I (2001) Opportunities and barriers for niche marketing of lamb in European LFAs based on consumer attitudes to product quality. Agrarwirtschaft 50(5):293-301

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