TY - JOUR
T1 - Above- and Belowground Trophic Interactions on Creeping Thistle (Cirsium arvense) in High- and Low-Diversity Plant Communities: Potential for Biotic Resistance?
AU - Bezemer, T.M.
AU - Graça, O.
AU - Rousseau, P.
AU - van der Putten, W.H.
PY - 2004
Y1 - 2004
N2 - The capacity of local communities to control introduced plants is called biotic resistance. Biotic resistance has been almost exclusively tested for plant competition and above-ground herbivores and pathogens, while neglecting root herbivores and soil pathogens. Here, we present biotic resistance by above- and below-ground herbivores in concert, and relate the abundance of the plant enemies to the species diversity of the local plant communities. The study was carried out in a 7-year-old biodiversity field experiment. We used creeping thistle (Cirsium arvense) as a model, and quantified sap-sucking herbivores: aboveground aphids, their antagonists, and root-feeding nematodes. As plant diversity treatments, we used field plots sown with high (15 plant species, HSD) or low (4 plant species, LSD) diverse seed mixtures in 1996 and that were not weeded. Creeping thistle became established spontaneously at the start of the experiment. In 2002, in HSD plots, 90% of the plant community was made up by 11 species, compared to seven species in LSD plots. No differences were found for C. arvense abundance or biomass. Aboveground, three aphid species were found on C. orvense-Uroleucon cirsii, Aphis fabae, and Macrosiphum euphorbiae, but the latter was found only in low densities. Significantly more aphid species were found on individual plants in HSD plots. Moreover, in HSD plots, on average 10% of aphids were parasitized, while no parasitism was observed in LSD plots. In the root zone of C arvense, significantly more nematodes were found in HSD than in LSD plots, and a significantly higher proportion of those nematodes were plant parasites. The dominant plant parasitic nematode in both treatments was Paratylenchus. We conclude that biotic resistance by natural enemies may be enhanced by plant species diversity, but that above- and below-ground sap-sucking herbivores do not necessarily have to respond similarly to the diversity of the surrounding plant community.
AB - The capacity of local communities to control introduced plants is called biotic resistance. Biotic resistance has been almost exclusively tested for plant competition and above-ground herbivores and pathogens, while neglecting root herbivores and soil pathogens. Here, we present biotic resistance by above- and below-ground herbivores in concert, and relate the abundance of the plant enemies to the species diversity of the local plant communities. The study was carried out in a 7-year-old biodiversity field experiment. We used creeping thistle (Cirsium arvense) as a model, and quantified sap-sucking herbivores: aboveground aphids, their antagonists, and root-feeding nematodes. As plant diversity treatments, we used field plots sown with high (15 plant species, HSD) or low (4 plant species, LSD) diverse seed mixtures in 1996 and that were not weeded. Creeping thistle became established spontaneously at the start of the experiment. In 2002, in HSD plots, 90% of the plant community was made up by 11 species, compared to seven species in LSD plots. No differences were found for C. arvense abundance or biomass. Aboveground, three aphid species were found on C. orvense-Uroleucon cirsii, Aphis fabae, and Macrosiphum euphorbiae, but the latter was found only in low densities. Significantly more aphid species were found on individual plants in HSD plots. Moreover, in HSD plots, on average 10% of aphids were parasitized, while no parasitism was observed in LSD plots. In the root zone of C arvense, significantly more nematodes were found in HSD than in LSD plots, and a significantly higher proportion of those nematodes were plant parasites. The dominant plant parasitic nematode in both treatments was Paratylenchus. We conclude that biotic resistance by natural enemies may be enhanced by plant species diversity, but that above- and below-ground sap-sucking herbivores do not necessarily have to respond similarly to the diversity of the surrounding plant community.
KW - host-plant
KW - root herbivory
KW - mediated interactions
KW - grassland ecosystems
KW - insect herbivores
KW - arable land
KW - soil
KW - responses
KW - biodiversity
KW - succession
U2 - 10.1055/s-2004-817846
DO - 10.1055/s-2004-817846
M3 - Article
SN - 1435-8603
VL - 6
SP - 231
EP - 238
JO - Plant Biology
JF - Plant Biology
IS - 2
ER -