I examined whether light availability mediated the extent to which herbivory by green frog tadpoles (Rana chmitans) affected lower trophic levels in a fishless pond in central Kentucky. An enclosure experiment manipulating tadpole presence/absence and light (shaded vs. unshaded) showed that tadpoles can significantly reduce benthic algal biomass in light levels that mimic springtime canopy conditions. Tadpoles, however, had little affect on algal species composition. Grazing did not indirectly affect nutrient (NO3and PO4) concentrations in experimental treatments, probably because ambient concentrations were beyond growth-limiting levels.