Tree species diversity affects decomposition through modified micro-environmental conditions across European forests.
Different tree species influence litter decomposition directly through species-specific litter traits, and indirectly through distinct modifications of the local decomposition environment. Whether these indirect effects on decomposition are influenced by tree species diversity is presently not clear. We addressed this question by studying the decomposition of two common substrates, cellulose paper and wood sticks, in a total of 209 forest stands of varying tree species diversity across six major forest types at the scale of Europe. Tree species richness showed a weak but positive correlation with the decomposition of cellulose but not with that of wood. Surprisingly, macroclimate had only a minor effect on cellulose decomposition and no effect on wood decomposition despite the wide range in climatic conditions among sites from Mediterranean to boreal forests. Instead, forest canopy density and stand-specific litter traits affected the decomposition of both substrates, with a particularly clear negative effect of the proportion of evergreen tree litter. Our study suggests that species richness and composition of tree canopies modify decomposition indirectly through changes in microenvironmental conditions. These canopy-induced differences in the local decomposition environment control decomposition to a greater extent than continental-scale differences in macroclimatic conditions.
CEFE UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, 1919 Route de Mende, Montpellier Cedex 5, FR-34293, France.
François-Xavier
FX
Joly
CEFE UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, 1919 Route de Mende, Montpellier Cedex 5, FR-34293, France.|CNRS, Ecotron - UPS 3248, Campus Baillarguet, Montferrier-sur-Lez, FR-34980, France.
Alexandru
A
Milcu
Geobotany, Faculty of Biology, University of Freiburg, Schänzlestr.1, Freiburg, DE-79104, Germany.
Michael
M
Scherer-Lorenzen
CEFE UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, 1919 Route de Mende, Montpellier Cedex 5, FR-34293, France.
Loreline-Katia
LK
Jean
Department of Agri-Food Production and Environmental Science, University of Firenze, Piazzale delle Cascine, 28, Firenze, IT-50144, Italy.
Filippo
F
Bussotti
Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, DK-1958, Denmark.
Seid Muhie
SM
Dawud
Geobotany, Faculty of Biology, University of Freiburg, Schänzlestr.1, Freiburg, DE-79104, Germany.
Sandra
S
Müller
Department of Agri-Food Production and Environmental Science, University of Firenze, Piazzale delle Cascine, 28, Firenze, IT-50144, Italy.
Martina
M
Pollastrini
Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, DK-1958, Denmark.
Karsten
K
Raulund-Rasmussen
Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg C, DK-1958, Denmark.
Lars
L
Vesterdal
CEFE UMR 5175, CNRS - Université de Montpellier - Université Paul-Valéry Montpellier - EPHE, 1919 Route de Mende, Montpellier Cedex 5, FR-34293, France.
Stephan
S
Hättenschwiler
D044822:Biodiversity; D005060:Europe; D065928:Forests; D016014:Linear Models; D018515:Plant Leaves / Q000502:physiology; D013045:Species Specificity; D014197:Trees / Q000502:physiology*; D014934:Wood / Q000502:physiology
FunDivEUROPE; cellulose decomposition; decomposition environment; litter functional diversity; litter functional traits; litter quality; species richness; wood decomposition