Interspecific variation in prairie plant biomass depends on phosphorus mining traits and mycorrhizal responsiveness in the American Northern Plains

Authors: Reinhart, Kurt; Vermeire, Lance; LEKBERG, YLVA - Mpg Ranch

Submitted to: Journal of Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/6/2026
Publication Date: 8/17/2026
Citation: Reinhart, K.O., Vermeire, L.T., Lekberg, Y. 2026. Interspecific variation in prairie plant biomass depends on phosphorus mining traits and mycorrhizal responsiveness in the American Northern Plains. Journal of Ecology. https://doi.org/10.1007/s11104-026-08971-0.
DOI: https://doi.org/10.1007/s11104-026-08971-0

Interpretive Summary: Problem- Much of the phosphorus in prairie and rangeland soils is “locked up” and unavailable for plants to use. This means plants must rely on special strategies to access it. Some plants grow roots that release natural chemicals to free up phosphorus, while others partner with soil fungi (mycorrhizae) to help them gather nutrients. But we still don’t fully understand which plant traits matter most for growth under low-phosphorus conditions, or why some species do better than others. Accomplishment- We studied 68 prairie plant species to learn which strategies help them grow in phosphorus-poor soils. By combining data on plant size, root traits, and fungal partnerships, we discovered that plants with certain types of roots and root activity grew best. Just a few simple measurements—how long and fine the roots are, and a leaf indicator of root chemical release—were surprisingly powerful predictors of a plant’s success.

Technical Abstract: 1. Prairie plants are predicted to either increase root mining or collaboration with mycorrhizal fungi in soils with low phosphorus (P) solubility. Unclear are the root traits that explain interspecific variation in growth. 2. We measured shoot [Mn] a proxy for root carboxylate production of 68 plant species from a mycorrhizal growth responsiveness (MGR) experiment with similar starting soil. This dataset was separately joined with two root structural trait datasets. This resulted in plant biomass, functional trait, and structural trait data for a 22-species Montana dataset and an 18 species Colorado-Wyoming dataset. We tested for predictors of plant biomass and evidence for either trait coordination or trade-offs. 3. Across all 68 species, shoot biomass was negatively related to MGR. Performance of forbs and C3 perennial grasses was positively correlated with shoot [Mn]. We detected a trade-off between shoot [Mn] and MGR for C4 perennial grasses. Total plant biomass was reliably predicted by the sum score of specific root length (SRL) and shoot [Mn]. 4. The predictive ability of traits to independently and interactively predict plant performance varied among plant functional groups. Specifically, the largest grasses (C3 perennials) relied on autonomous root functional (e.g. intermediate carboxylate exudation) and structural traits (e.g. ' SRL) to efficiently mine calcium bound P. Conversely, C4 grasses were less productive and efficient at resource acquisition because of their inability to effectively coordinate root structural, functional, and mycorrhizal traits. The sum score of root functional and structural traits reliably predicted plant performance, suggesting the composite variable moderated species-specific cases of trait coordination and trade-offs. 5. Synthesis: In soils with little soluble P, individual plant performance was often positively related to an indicator of rhizosphere carboxylate production and negatively related to mycorrhizal responsiveness. In drylands with low soluble P, overall plant production is likely to depend on the growth of efficient P mobilizing plants. Plant diversity may be maintained by subordinate plants with complementary P-acquisition strategies including those that rely on P-mobilizing neighbors and others that can persist at low levels of soluble P.