Relationships among ecologically important dimensions of plant trait variation in seven neotropical forests.
OBJECTIVE
When ecologically important plant traits are correlated they may be said to constitute an ecological 'strategy' dimension. Through identifying these dimensions and understanding their inter-relationships we gain insight into why particular trait combinations are favoured over others and into the implications of trait differences among species. Here we investigated relationships among several traits, and thus the strategy dimensions they represented, across 2134 woody species from seven Neotropical forests.


METHODS
Six traits were studied: specific leaf area (SLA), the average size of leaves, seed and fruit, typical maximum plant height, and wood density (WD). Trait relationships were quantified across species at each individual forest as well as across the dataset as a whole. 'Phylogenetic' analyses were used to test for correlations among evolutionary trait-divergences and to ascertain whether interspecific relationships were biased by strong taxonomic patterning in the traits.


RESULTS
The interspecific and phylogenetic analyses yielded congruent results. Seed and fruit size were expected, and confirmed, to be tightly related. As expected, plant height was correlated with each of seed and fruit size, albeit weakly. Weak support was found for an expected positive relationship between leaf and fruit size. The prediction that SLA and WD would be negatively correlated was not supported. Otherwise the traits were predicted to be largely unrelated, being representatives of putatively independent strategy dimensions. This was indeed the case, although WD was consistently, negatively related to leaf size.


CONCLUSIONS
The dimensions represented by SLA, seed/fruit size and leaf size were essentially independent and thus conveyed largely independent information about plant strategies. To a lesser extent the same was true for plant height and WD. Our tentative explanation for negative WD-leaf size relationships, now also known from other habitats, is that the traits are indirectly linked via plant hydraulics.
Wright
Ian J
IJ
Department of Biological Sciences, Macquarie University, New South Wales 2109, Australia. iwright@rna.bio.mq.edu.au
Ackerly
David D
DD
Bongers
Frans
F
Harms
Kyle E
KE
Ibarra-Manriquez
Guillermo
G
Martinez-Ramos
Miguel
M
Mazer
Susan J
SJ
Muller-Landau
Helene C
HC
Paz
Horacio
H
Pitman
Nigel C A
NC
Poorter
Lourens
L
Silman
Miles R
MR
Vriesendorp
Corine F
CF
Webb
Cam O
CO
Westoby
Mark
M
Wright
S Joseph
SJ
D005075:Biological Evolution; D004463:Ecology; D017753:Ecosystem; D005638:Fruit / Q000033:anatomy & histology; D015999:Multivariate Analysis; D010802:Phylogeny; D018515:Plant Leaves / Q000033:anatomy & histology; D010944:Plants / Q000033:anatomy & histology*; D012639:Seeds / Q000033:anatomy & histology; D014197:Trees; D014329:Tropical Climate