Effects of periodic trampling on the abundance of mobile animals within Hormosira banksii dominated rocky intertidal communities

This study assesses the effects of trampling on Hormosira banksii dominated rocky intertidal algal beds within Point Nepean National Park over six summers between 1991 and 1996. This dataset gives the number of mobile animals (N per m2) within beds of Hormosira banksii after exposure to four levels of experimental trampling for 3 and 5 years. Sites were located at Cheviot Beach (Harry's pool, Cheviot Mid) or at Grenade Range, ~ 1 km apart. The number of mobile animals were sampled in the Autumn of 1993 and 1995, after 3 and 5 years of summer trampling, respectively. Trampling increased the abundance of a number of herbivorous molluscs, particularly limpet abundance. The effect of trampling on the abundance of mollusks may be indirect as changes in the abundance of mollusks occurred only after changes in the cover of Hormosira.