To investigate the potential significance of virus-mediated mortality for early survivorship of bunchgrass seedlings, Malmstrom et al. compared the separate and combined effects of virus infection, competition and simulated grazing in a field experiment. Although virus infection alone did not reduce first-year survivorship, it halved the survivorship of bunchgrasses competing with exotics. Within an environment in which competition strongly reduces seedling survivorship, virus infection therefore has the power to cause additional seedling mortality and alter patterns of establishment. Clipping did not reduce bunchgrass survivorship further, but doubled it and disproportionately increased survivorship of infected bunchgrasses. This study suggests that barley and cereal yellow dwarf viruses can be potentially powerful agents in California grasslands. The findings demonstrate the potential significance of multitrophic interactions in virus ecology. Although sometimes treated as plant predators, viruses and herbivores may exert influences that are distinctly different, even counteracting.
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.