At all sites, the experimental treatments were located low in the mid-intertidal zone, which is dominated by a band of macroalgal growth.The rockweed Ascophyllum nodosum (L.) Le Jolis
is the dominant macroalga at J4, LI, and DR. Fucus vesiculosus L. is more common at
LO. The barnacle Semibalanus balanoides is common where macroalgae are absent and
rare in the presence of a macroalgal canopy.