High rates of herbivory in remote northwest Australian seagrass meadows by rabbitfish and green turtles

Herbivory is a key ecological process that often determines the composition and abundance of plants. Estimates herbivory in seagrass meadows are typically lower than those other vegetated coastal ecosystems, but can be intense when large herbivorous vertebrates abundant. We surveyed rates on 2 species tropical seagrasses ( Thalassia hemprichii Enhalus acoroides ), vertebrates, diet abundant (the green turtle Chelonia mydas rabbitfish Siganus lineatus ) lagoons adjacent to remote islands off northwestern Australia. Rates some deployments tethered were more 1000 times higher production among highest recorded. Consumption exceeded half (9 18). Remote underwater video revealed S. was most herbivore. Stomachs contained mostly seagrass, models based stable isotopes indicated primary source nutrition. Stomach contents C. variable, containing macroalgae (although sample size low), likely Multiple lines evidence suggest high T. E. mainly due direct consumption by , perhaps also . Seagrass contributor nutrition both species.