Time course of plant diversity effects on Centaurea jacea establishment and the role of competition and herbivory  

作　　者：Norma Nitschke Anne Ebeling Tanja Rottstock Christoph Scherber Cornelius Middelhoff Sylvia Creutzburg Alexandra Weigelt Teja Tscharntke Markus Fischer Wolfgang WWeisser 

机构地区：[1]Institute of Ecology,Friedrich-Schiller-University Jena,Dornburger Strasse 159,07743 Jena,Germany [2]Agroecology,Georg-August-University Gottingen,Waldweg 26,37073 Gottingen,Germany [3]Institute of Biochemistry and Biology,University of Potsdam,Maulbeerallee 1,14469 Potsdam,Germany [4]Max-Planck-Institute for Biogeochemistry,Hans-Knoll-Strasse 10,07745 Jena,Germany [5]Institute of Biology I,University of Leipzig,Johannisallee 21-23,04103,Leipzig,Germany [6]Institute of Plant Sciences,University of Bern,Altenbergrain 21,3013 Bern,Switzerland

出　　处：《Journal of Plant Ecology》2010年第2期109-121,共13页植物生态学报（英文版）

摘　　要：Aims Invasion resistance in experimental plant communities is known to increase with increasing diversity and further to depend on the presence of particular functional groups.To test whether these effects also hold true for the invader establishment phase beyond the seedling stage,we studied survival and performance of Centaurea jacea L.(brown knapweed)planted into experimental grassland communities of varying plant biodiversity over three consecutive years.Moreover,we analysed the role of insect herbivory and biomass of the recipient community for mediating diversity effects.Methods In 2005,seedlings of Centaurea were transplanted into experimental grassland communities(the Jena Experiment)covering a species richness(1–60)and functional group richness(1–4)gradient.Half of these transplants and the community surrounding them in each plot were sprayed with insecticide while the other half served as control.In 2006 and 2007(during the second and third year after transplantation),we recorded survival,growth-related(e.g.transplant biomass,height)and reproduction-related traits(e.g.number of flower heads).Annual data on community aboveground biomass served as covariate to investigate mediating effects of aboveground competition with the recipient community.Important Findings Species richness was the most important factor responsible for Centaurea limitation.Higher levels of diversity decreased survival and all performance traits in both years.These diversity effects were partly driven by community biomass,but not fully explained by that covariate,suggesting the importance also of further processes.The influence of functional group richnesswas strong in the second year after transplantation and weaker in the third year.Among the particular functional groups,only the presence of legumes showed strong negative effects on Centaurea survival and weak negative effects on growth and reproduction,the latter two being mediated by biomass.Insect herbivore reduction considerably benefited Centaurea in sprayed monocultures,w

关 键 词：invasion resistance aboveground competition biomass Jena Experiment experimental grassland Centaurea jacea 

分 类 号：TG1[金属学及工艺—金属学]