Document Detail

Changes in herbivore control in arable fields by detrital subsidies depend on predator species and vary in space.
MedLine Citation:
PMID:  20349249     Owner:  NLM     Status:  MEDLINE    
Prey from the decomposer subsystem may help sustain predator populations in arable fields. Adding organic residues to agricultural systems may therefore enhance pest control. We investigated whether resource addition (maize mulch) strengthens aboveground trophic cascades in winter wheat fields. Evaluating the flux of the maize-borne carbon into the food web after 9 months via stable isotope analysis allowed differentiating between prey in predator diets originating from the above- and belowground subsystems. Furthermore, we recorded aphid populations in predator-reduced and control plots of no-mulch and mulch addition treatments. All analyzed soil dwelling species incorporated maize-borne carbon. In contrast, only 2 out of 13 aboveground predator species incorporated maize carbon, suggesting that these 2 predators forage on prey from the above- and belowground systems. Supporting this conclusion, densities of these two predator species were increased in the mulch addition fields. Nitrogen isotope signatures suggested that these generalist predators in part fed on Collembola thereby benefiting indirectly from detrital resources. Increased density of these two predator species was associated by increased aphid control but the identity of predators responsible for aphid control varied in space. One of the three wheat fields studied even lacked aphid control despite of mulch-mediated increased density of generalist predators. The results suggest that detrital subsidies quickly enter belowground food webs but only a few aboveground predator species include prey out of the decomposer system into their diet. Variation in the identity of predator species benefiting from detrital resources between sites suggest that, depending on locality, different predator species are subsidised by prey out of the decomposer system and that these predators contribute to aphid control. Therefore, by engineering the decomposer subsystem via detrital subsidies, biological control by generalist predators may be strengthened.
Karsten von Berg; Carsten Thies; Teja Tscharntke; Stefan Scheu
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-03-28
Journal Detail:
Title:  Oecologia     Volume:  163     ISSN:  1432-1939     ISO Abbreviation:  Oecologia     Publication Date:  2010 Aug 
Date Detail:
Created Date:  2010-07-14     Completed Date:  2010-10-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0150372     Medline TA:  Oecologia     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  1033-42     Citation Subset:  IM    
Animal Ecology, Darmstadt University of Technology, Schnittspahnstr 3, 64287 Darmstadt, Germany.
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MeSH Terms
Agriculture / methods
Carbon Radioisotopes / analysis
Food Chain*
Nitrogen Isotopes / analysis
Pest Control, Biological*
Soil* / analysis
Triticum / parasitology
Zea mays
Reg. No./Substance:
0/Carbon Radioisotopes; 0/Nitrogen Isotopes; 0/Soil

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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