Food web structure and biocontrol in a four-trophic level system across a landscape complexity gradient

Vesna Gagic, Teja Tscharntke, Carsten Dorman, Bernd Gruber, Anne Wilstermann, Carsten Thies

Research output: Contribution to journalArticlepeer-review

128 Citations (Scopus)


Decline in landscape complexity owing to agricultural intensification may affect biodiversity, food web complexity and associated ecological processes such as biological control, but such relationships are poorly understood. Here, we analysed food webs of cereal aphids, their primary parasitoids and hyperparasitoids in 18 agricultural landscapes differing in structural complexity (42â¿¿93% arable land). Despite little variation in the richness of each trophic group, we found considerable changes in trophic link properties across the landscape complexity gradient. Unexpectedly, aphidâ¿¿parasitoid food webs exhibited a lower complexity (lower linkage density, interaction diversity and generality) in structurally complex landscapes, which was related to the dominance of one aphid species in complex landscapes. Nevertheless, primary parasitism, as well as hyperparasitism, was higher in complex landscapes, with primary parasitism reaching levels for potentially successful biological control. In conclusion, landscape complexity appeared to foster higher parasitism rates, but simpler food webs, thereby casting doubt on the general importance of food web complexity for ecosystem functioning.
Original languageEnglish
Pages (from-to)2946-2953
Number of pages8
JournalRoyal Society of London. Proceedings B. Biological Sciences
Issue number1720
Publication statusPublished - 2011


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