Dawson L.A., Grayston S.J., Murray P.J., Paterson E. and Treonis A.M.

Research to date has concentrated on the effects of grazing on above-ground aspects, but the effects of herbivory on the timing, mass and quality of below-ground inputs remains one of the unresolved issues of the dynamics of nutrient cycling. The soil microbiota in grasslands consists of populations of microorganisms including bacteria, fungi, protozoa, nematodes, and micro and macro-arthropod groups. They all rely to some extent for their growth on carbon or nitrogen substrates via litter, root production, sloughage and exudation. In addition, considerable numbers of root herbivores existing in grassland soil rely on live plant roots for their survival. Any alteration in plant derived carbon such as through shoot herbivory will have consequences at many levels of the food web. In addition, the effects of invertebrate root feeders on plant growth and competition can also have large effects. This work focuses on contrasting effects between species, and demonstrates effects on root systems while also considering the impacts on rhizosphere carbon flow, and the consequent effects on the soil.