Coordination of leaf, root, and seed traits shows the importance of whole plant economics in two semiarid grasslands

Authors: MUELLER, KEVIN - Cleveland State University; Blumenthal, Dana; Kray, Julie

Submitted to: New Phytologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2023
Publication Date: 1/12/2024
Citation: Mueller, K.E., Blumenthal, D.M., Kray, J.A. 2024. Coordination of leaf, root, and seed traits shows the importance of whole plant economics in two semiarid grasslands. New Phytologist. https://doi.org/10.1111/nph.19529.
DOI: https://doi.org/10.1111/nph.19529

Interpretive Summary: To use plant traits for understanding and managing rangeland ecosystems it is critical to understand how rangeland plant species coordinate aboveground and belowground functions. Across 55 species from shortgrass steppe and mixedgrass prairie, we determined that multiple leaf and root traits were positively correlated with one another. For example, plants with nitrogen-rich leaves tended to also have nitrogen-rich roots. Seed mass, an aboveground trait related to dispersal and recruitment, was positively correlated with root diameter. Traits were also predictive of abundance: species with high leaf dry matter content tended to be relatively abundant. The strengths of these trait associations, particularly those between aboveground and belowground traits, may be related to the degree of water limitation in these two semiarid rangeland ecosystems.

Technical Abstract: • Uncertainty persists within trait-based ecology, partly because few studies assess multiple axes of functional variation and their affect on plant performance. • For 55 species from two semiarid grasslands, we quantified: i) covariation between economic traits of leaves and absorptive roots, ii) covariation among economic traits, plant height, leaf size, and seed mass, and iii) relationships between these traits and species’ abundance. • Pairs of analogous leaf and root traits were at least weakly positively correlated (e.g., SLA and SRL) and two pairs of traits (N content and DMC of leaves and roots) were at least moderately correlated (r > 0.5) whether species were grouped by site, taxonomic group and growth form, or life history. Root diameter was positively and moderately correlated with seed mass for all groups of species except annuals and monocots. Species with higher LDMC tended to be more abundant (R2=0.4). • Compared to global-scale syntheses that include many observations from more mesic ecosystems, we observed stronger correlations between analogous leaf and root traits, weaker correlations between SLA and leaf N, and stronger correlations between SRL and root N. Additional comprehensive and community-scale studies are needed to elucidate how trait co-variation depends on environmental factors (e.g., the extent of water-limitation).