Leaf traits within communities: Context may affect the mapping of traits to function

Abstract

Abstract. The leaf economics spectrum (LES) has revolutionized the way many ecologists think about quantifying plant ecological trade-offs. In particular, the LES has connected a clear functional trade-off (long-lived leaves with slow carbon capture vs. short-lived leaves with fast carbon capture) to a handful of easily measured leaf traits. Building on this work, community ecologists are now able to quickly assess species carbon-capture strategies, which may have implications for community-level patterns such as competition or succession. However, there are a number of steps in this logic that require careful examination, and a potential danger arises when interpreting leaf-trait variation among species within communities where trait relationships are weak. Using data from 22 diverse communities, we show that relationships among three common functional traits (photosynthetic rate, leaf nitrogen concentration per mass, leaf mass per area) are weak in communities with low variation in leaf life span (LLS), especially communities dominated by herbaceous or deciduous woody species. However, globally there are few LLS data sets for communities dominated by herbaceous or deciduous species, and more data are needed to confirm this pattern. The context-dependent nature of trait relationships at the community level suggests that leaf-trait variation within communities, especially those dominated by herbaceous and deciduous woody species, should be interpreted with caution.

Functional traits explain variation in plant life history strategies

“…SLA explained less variation in demographic rates than wood density or seed size (18,23) and that SLA values are variable and context-dependent (42,43). We also found that SLA and leaf N had stronger relationships with elasticities to fecundity than growth, an unexpected result given the strong positive correlation between these traits and relative growth rates (1).…”

Seedling root responses to soil moisture and the identification of a belowground trait spectrum across three growth forms

“…Importantly, our detection of a single root trait spectrum linked to plant growth suggests that measuring one or two aspects of root growth morphology, such as root elongation rate, could be indicative of larger belowground strategies across species. Still, trait relationships may vary depending on resource availability (as demonstrated here) or on community types (Funk & Cornwell, 2013), and the traits measured in this study may not capture all aspects of seedling response to resource pulses, severe stress, or biotic interactions. Moving forward, it will be critical to explore and identify the scope of functional traits necessary to capture belowground strategies and plant responses, including plasticity-related metrics, across a range of ecosystems.…”

Trait variation and integration across scales: is the leaf economic spectrum present at local scales?

“…In a meta-analysis, Funk and Cornwell (2013) argue that the strength of the LES relationships depends on the variation in leaf life span (LL). This variability in LL can be genetic and is often an adaptation to distinct climatic regimes or life-histories.…”