Webbläsaren som du använder stöds inte av denna webbplats. Alla versioner av Internet Explorer stöds inte längre, av oss eller Microsoft (läs mer här: * https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Var god och använd en modern webbläsare för att ta del av denna webbplats, som t.ex. nyaste versioner av Edge, Chrome, Firefox eller Safari osv.

Trophic structure and major trophic links in conventional vs organic farming systems as indicated by carbon stable isotope ratios of fatty acids

In English

Författare

  • Dominique Haubert
  • Klaus Birkhofer
  • Andreas Fließbach
  • Matthias Gehre
  • Stefan Scheu
  • Liliane Ruess

Summary, in English

Using bulk tissue and fatty acid 13C analysis we investigated major trophic pathways from soil microorganisms to microbial consumers to predators in conventional versus organic farming systems planted for the first time with maize. Organic farming led to an increase in microbial biomass in particular that of fungi as indicated by phospholipid fatty acids (PLFAs). Microbial PLFAs reflected the conversion from C3 to C4 plants by a shift in δ13C of 2‰, whereas the isotopic signal in fatty acids (FAs) of Collembola was much more pronounced. In the euedaphic Protaphorura fimata the δ13C values in maize fields exceeded that in C3 (soybean) fields by up to 10‰, indicating a close relationship between diet and vegetation cover. In the epedaphic Orchesella villosaδ13C values shifted by 4‰, suggesting a wider food spectrum including carbon of former C3 crop residues. Differences in δ13C of corresponding FAs in consumers and resources were assessed to assign food web links. P. fimata was suggested as root and fungal feeder in soybean fields, fungal feeder in conventional and leaf consumer in organically managed maize fields. O. villosa likely fed on root and bacteria under soybean, and bacteria and fungi under maize. Comparison of δ13C values in FAs of the cursorial spider Pardosaagrestis and O. villosa implied the latter as important prey species in soybean fields. In contrast, the web-building spider Mangora acalypha showed no predator–prey relationship with Collembola. The determination of δ13C values in trophic biomarker FAs allowed detailed insight into the structure of the decomposer food web and identified diet-shifts in both consumers at the base of the food web and in top predators in organic versus conventional agricultural systems. The results indicate changes in major trophic links and therefore carbon flux through the food web by conversion of conventional into organic farming systems.

Avdelning/ar

Publiceringsår

2009

Språk

Engelska

Sidor

1579-1589

Publikation/Tidskrift/Serie

Oikos

Volym

118

Issue

10

Dokumenttyp

Artikel i tidskrift

Förlag

Wiley-Blackwell

Ämne

  • Ecology

Status

Published

ISBN/ISSN/Övrigt

  • ISSN: 1600-0706