In this study, Merrill et al. sampled above and belowground biomass of Idaho fescue (Festuca idahoensis) and bluebunch wheatgrass (Agropyron spicatum) plants, as well as nematode densities associated with these species, inside and outside a 2-year old exclosure on the northern range of Yellowstone National Park in 1990. Grazing during the winter and early spring removed essentially all the standing dead plant material. Indirect effects of grazing, such as the effects of removing standing dead material on microclimate conditions, likely influenced early growth. By the end of the growing season, both species had similar biomass to ungrazed plants despite an increase in root-feeding nematodes early in the growing season. Lower root biomass, higher densities of bacteria-feeding nematodes, and higher concentrations in foliar nitrogen with grazing suggested that root mortality, due to spring grazing, provided short-term source of carbon for microbial activity and that microbial-feeding nematodes increased the turnover rates of microbial bound N. Because N concentrations of roots did not differ between grazed and ungrazed plants, it is suggested that there was a reduction in secondary chemicals or an increase in root hairs which are preferred sites for nematode feeding.
Citations and enhanced abstracts for journals articles and documents focused on rangeland ecology and management. RSIS is a collaboration between Montana State University, University of Idaho, and University of Wyoming.