Decomposing functional trait associations in a Chinese subtropical forest

Created at: 2019-10-09

Envisaged journal: PLos One https://doi.org/10.1371/journal.pone.0175727

Envisaged date: 2017-03-30

Rationale

Functional traits, properties of organisms correlated with ecological performance, play a cen-
tral role in plant community assembly and functioning. To some extents, functional traits vary
in concert, reflecting fundamental ecological strategies. While “trait syndromes” characteristic
of e.g. fast-growing, early-successional vs. competitive, late-successional species are recog-
nized in principle, less is known about the environmental and genetic factors at the source of
trait variation and covariation within plant communities. We studied the three leaf traits leaf
half-life (LHL), leaf mass per area (LMA) and nitrogen concentration in green leaves (N green )
and the wood trait wood density (WD) in 294 individuals belonging to 45 tree or shrub species
in a Chinese subtropical forest from September 2006 to January 2009. Using multilevel
ANOVA and decomposition of sums of products, we estimated the amount of trait variation
and covariation among species (mainly genetic causes), i.e. plant functional type (deciduous
vs. evergreen species), growth form (tree vs. shrub species), family/genus/species differ-
ences, and within species (mainly environmental causes), i.e. individual and season. For sin-
gle traits, the variation between functional types and among species within functional types
was large, but only LMA and N green varied significantly among families and thus showed phy-
logenetic signal. Trait variation among individuals within species was small, but large temporal
variation due to seasonal effects was found within individuals. We did not find any trait varia-
tion related to soil conditions underneath the measured individuals. For pairs of traits, varia-
tion between functional types and among species within functional types was large, reflecting
a strong evolutionary coordination of the traits, with LMA, LHL and WD being positively corre-
lated among each other and negatively with N green . This integration of traits was consistent
with a putative stem-leaf economics spectrum ranging from deciduous species with thin, high-
nitrogen leaves and low-density wood to evergreen species with thick, low-nitrogen leaves
and dense wood and was not influenced by phylogenetic history. Trait coordination within
species was weak, allowing individual trees to deviate from the interspecific trait coordination
and thus respond flexibly to environmental heterogeneity. Our findings suggest that within a
single woody plant community variation and covariation in functional traits allows a large num-
ber of species to co-exist and cover a broad spectrum of multivariate niche space, which in
turn may increase total resource extraction by the community and community functioning.

Datasets (1)

Calculated Authors

Xuefei Li Pascal Niklaus, PD Dr. Kequan Pei Bernhard Schmid, Prof.

Data request state

Preparation Project Board Data Requests Finished