Leaf area development strategies of cover plants used in banana plantations identified from a set of plant traits

• Four functional traits were used to identify leaf area development strategies.
• Strong correlations were observed between these traits, suggesting trade-offs.
• Four strategies were identified from PCA and cluster analyses.
• The strategies did not significantly differ in leaf area developed after 1 month.
• Better performance trends for two strategies were, however, observed.

Cover crops introduced into cropping systems can lead to chemical input reductions and pollution mitigation because they enhance ecological functions. The choice of the best cover crops for a specific cropping system is, however, difficult because of the large range of potential cover species. A promising method involves functional traits as simplified indicators of plant functions. In banana cropping systems, cover crops are used especially to control weeds by development of their leaf area to boost competition for light. The aim of this study was to seek trait-based leaf area development strategies among tropical cover species, based on four plant traits chosen because of their mathematical link with leaf area development: specific leaf area (SLA), aboveground leaf mass fraction (LMFa), seed mass (SM) and aboveground relative growth rate (RGRa). We measured trait values and leaf areas of 17 tropical cover species grown for 1 month in a growth chamber. Strong positive and negative covariations were observed between SM, LMFa and RGRa, revealing a “syndrome” of traits and suggesting trade-offs between traits. Four groups of species were identified based on PCA and cluster analyses and were characterized by significantly different sets of trait values. They showed four leaf area development strategies: species that allocate a large part of biomass to leaf area (G1), species that develop large biomass and leaf area at emergence (G2), species with rapid biomass growth and low biomass investment in leaves (G3) and species with a non-specialized strategy (G4). After 1 month, species of groups G1 and G2 had higher leaf area, although not significantly, than species of groups G3 and G4. Comparisons between this functional classification and the taxonomic monocot/dicot classification showed that the functional classification captured a larger part of the variability in traits involved in leaf area development than the taxonomic monocot/dicot classification. This encourages the use of such a classification to describe plant functioning, to understand plant roles in plant–plant interactions and guide the choice of the best cover species to introduce into cropping systems.