Historical manoomin (Zizania palustris) stands have been drastically reduced within the Great Lakes region due to wetland disturbances, eutrophication, and invasive species establishment (i.e. Typha x glauca; Myriophyllum spicatum). Manoomin is a species of high cultural and ecological importance, thus establishing self-sustaining populations is a priority for tribal communities and wetland managers. Long-term adaptive restoration research indicates that harvesting Typha biomass reduces dominance, while producing biochar from collected feedstocks offers a closed-loop restoration pathway for sustainable wetland management. Biochar, a negatively charged carbon product of organic matter pyrolysis, increases crop growth, retains soil nutrients, and increases microbial activity when applied in agricultural settings. However, the impact of wetland biochar application on manoomin is unknown. To assess this, we established a fully factorial mesocosm study to assess the response of seeded manoomin grown in competition (M. spicatum present; M. spicatum absent) with Typha-derived biochar application (0 metric tons / hectare (T/ha); 50 T/ha biochar) over 12 weeks (replication = 8). Our findings indicate that biochar application significantly increased manoomin growth and ovary development regardless of M. spicatum presence (p < 0.001), as well as M. spicatum growth. Thus, biochar may increase the manoomin stand development although caution should be taken when M. spicatum is present.
