Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment.
Biodiversity is rapidly declining, and this may negatively affect ecosystem processes, including economically important ecosystem services. Previous studies have shown that biodiversity has positive effects on organisms and processes across trophic levels. However, only a few studies have so far incorporated an explicit food-web perspective. In an eight-year biodiversity experiment, we studied an unprecedented range of above- and below-ground organisms and multitrophic interactions. A multitrophic data set originating from a single long-term experiment allows mechanistic insights that would not be gained from meta-analysis of different experiments. Here we show that plant diversity effects dampen with increasing trophic level and degree of omnivory. This was true both for abundance and species richness of organisms. Furthermore, we present comprehensive above-ground/below-ground biodiversity food webs. Both above ground and below ground, herbivores responded more strongly to changes in plant diversity than did carnivores or omnivores. Density and richness of carnivorous taxa was independent of vegetation structure. Below-ground responses to plant diversity were consistently weaker than above-ground responses. Responses to increasing plant diversity were generally positive, but were negative for biological invasion, pathogen infestation and hyperparasitism. Our results suggest that plant diversity has strong bottom-up effects on multitrophic interaction networks, with particularly strong effects on lower trophic levels. Effects on higher trophic levels are indirectly mediated through bottom-up trophic cascades.
Scherber
Christoph
C
Georg-August-University Göttingen, Department of Crop Sciences, Agroecology, Grisebachstrasse 6, 37077 Göttingen, Germany. christoph.scherber@agr.uni-goettingen.de
Eisenhauer
Nico
N
Weisser
Wolfgang W
WW
Schmid
Bernhard
B
Voigt
Winfried
W
Fischer
Markus
M
Schulze
Ernst-Detlef
ED
Roscher
Christiane
C
Weigelt
Alexandra
A
Allan
Eric
E
Bessler
Holger
H
Bonkowski
Michael
M
Buchmann
Nina
N
Buscot
François
F
Clement
Lars W
LW
Ebeling
Anne
A
Engels
Christof
C
Halle
Stefan
S
Kertscher
Ilona
I
Klein
Alexandra-Maria
AM
Koller
Robert
R
König
Stephan
S
Kowalski
Esther
E
Kummer
Volker
V
Kuu
Annely
A
Lange
Markus
M
Lauterbach
Dirk
D
Middelhoff
Cornelius
C
Migunova
Varvara D
VD
Milcu
Alexandru
A
Müller
Ramona
R
Partsch
Stephan
S
Petermann
Jana S
JS
Renker
Carsten
C
Rottstock
Tanja
T
Sabais
Alexander
A
Scheu
Stefan
S
Schumacher
Jens
J
Temperton
Vicky M
VM
Tscharntke
Teja
T
D000818:Animals; D044822:Biodiversity; D008954:Models, Biological; D018521:Plant Physiological Phenomena; D011156:Population Density