Clonality-Related Traits Add Independent Specialization Axes to Herbs' Trait Strategies

The functional diversity of vascular plants is remarkable. Yet, previous studies showed that trait trade-offs constrain aboveground or fine-root trait variation. How do neglected functions such as resprouting and clonal growth, key for fitness maintenance in some plant groups, integrate in these trait frameworks? By using an extensive dataset (> 2000 species) spanning aboveground, fine-root and clonality-related traits of herbs, we asked whether clonal traits relate to species positioning in the aboveground or fine-root trait spaces. Clonal and non-clonal herbs were undistinguishable in the aboveground or fine-root trait spaces. Clonality-related traits were also weakly coordinated with the other trait dimensions. Altogether, these results suggest that clonality-related traits add independent functional specialization axes to plants trait strategies. We identified two potential specialization axes in clonal traits. The first axis summarizes the positive scaling between bud bank size and persistence of clonal connections, reflecting species specialization for on-spot persistence and tolerance to disturbance (persistence axis). The second axis, summarizes the positive scaling between multiplication rate and lateral spread, reflecting specialization for clonal multiplication and acquiring new space in horizontal dimension (clonal multiplication axis). We call for integrating these axes in existing strategy schemes to fully elucidate the multidimensional trait strategies of plants.