Co-Variations in Litter Decomposition, Leaf Traits and Plant Growth in Species from a Mediterranean Old-Field Succession

1. A growing consensus is developing that the impact of species on ecosystem properties is mediated, at least partially, by the traits of their component species. A previous study demonstrated that the field decomposition of complex litters produced by different communities of a Mediterranean successional sere was related to the average trait value of these communities. Here we scale down to the species level, to test whether similar relationships are found for selected species from these communities. We also test whether litter decomposability can be considered as part of the suite of traits characterizing the fast-slow growth continuum in plants. 2. We chose 12 of the most abundant herbaceous species characteristics of three stages of the old-field succession mentioned above. We investigated trait variation and covariation for the eight following traits: specific leaf area (SLA), leaf phosphorus (LPC), nitrogen (LNC) and carbon (LCC) concentrations, leaf dry matter content (LDMC) and leaf total phenols (TPh), all on material collected in the field; and litter decomposability$(K_{\text{pot}})$and maximum relative growth rate$(\text{RGR}_{\text{max}})$, obtained under standardized conditions in the laboratory. 3. Five of these traits were significantly lower in species from the advanced successional stage. These trends were similar when comparisons were conducted either with the 12 species, or on a subset incorporating taxonomic information. LDMC was the single trait best correlated with species$\text{RGR}_{\text{max}}$and$K_{\text{pot}}$; the two latter traits were also significantly correlated with one another. 4. These results provide clear evidence of functional links between plant growth, leaf traits and litter decomposability. LDMC appears as a pivotal trait of living leaves related to their structural properties. It influences the quality of the litter produced, and hence species' potential 'after-life effects' on ecosystem properties.