Growth dynamics and associated mycorrhizal fungi of little bluestem grass [Schizachyrium scoparium (Michx.) Nash] on burned and unburned sand prairies

Abstract

SUMMARYWe examined the influence of burning on little bluestem grass productivity and its vesicular-arbuscular mycorrhizal (VAM) fungal associates in a sand prairie community over four growing seasons (1986-9), Aboveand below-ground productivity was higher on the burned sites than on the unburned sites. Percent VAM fungal colonization levels were significantly lower on burned sites than on the unburned sites. In contrast, early in the growing season, colonized and specific root lengths were longer on the burned site than on the unburned sites but differences were not always significant. Roots of plants on the burned sites supported more fungal biomass than roots on the unburned sites especially during the early growing season. However, colonization data suggest that the fungi were unable to keep up with the greater below-ground production of plants on the burned prairies. Mycorrhizal inoculum potential levels of little bluestem root zone and randomly collected soil and VAM fungal spore densities were lower on the burned sites than the unburned sites during the year of the burn. Above-and below-ground tissue samples showed significantly higher concentrations and accumulations of several inorganic nutrients on the burned site than the unburned site early and later in the growing season. However, in contrast, plants on the unburned sites had greater nutrient-use efiSciencies for several nutrients than plants on the burned sites. Lower nutrient-use efficiencies of plants on burned sites may in part be due to the onset of harsher environmental conditions during the growing season and/or to associated VAM fungi, VAM fungi associated with plants on the burned sites are likely a carbon drain on these plants, supporting greater fungal biomass, and hence, plants on burned sand prairie sites may not benefit from their VAM fungal association especially early in the growing season.

Small‐scale spatial variability in the distribution of ectomycorrhizal fungi affects plant performance and fungal diversity

“…EM fungi colonise plant roots by forming an intercellular interface consisting of highly branched hyphae, while also forming a dense hyphal sheath, surrounding the root surface. This entire hyphal network aids in increasing root surface area (Smith & Read ), thus improving plant access to nutrients (Dhillion & Anderson ) and water (Lehto & Zwiazek ). Plant roots are colonised by one to many EM fungal species as they grow and encounter EM fungal spores or hyphae.…”

The use of pasture reflectance characteristics and arbuscular mycorrhizal root colonization to predict pasture characteristics of tallgrass prairie grazed by cattle and bison

“…In comparison, grazed pastures had both smaller fuel load and an increased number of 'patchy' areas, particularly in the pastures grazed by bison, resulting in less intense and incomplete burns in grazed compared with ungrazed pastures, as has been reported by others (England and DeVos, 1969;Hobbs, 1996;Knapp et al, 1999;Bakker et al, 2003). Mycorrhizal root colonization may decrease due to burning (Dhillon et al, 1988;Dhillon and Anderson, 1993). In contrast, increases in AMF colonization (Bentivenga and Hetrick, 1991) and spore abundance (Eom et al, 1999) have been reported as short-term burning effects on tallgrass prairie.…”

“…Mycorrhizal root colonization may decrease due to burning (Dhillon et al. , 1988; Dhillon and Anderson, 1993). In contrast, increases in AMF colonization (Bentivenga and Hetrick, 1991) and spore abundance (Eom et al.…”