Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior - Fig 1

(A) Green (Lytechinus semituberculatus) and pencil (Eucidaris galapagensis) sea urchins on the exposed rocky substrate, 8 m depth, Galápagos Islands and (B) close-up of a patch of substrate on the bases grazed by pencil urchins in the TC experiment. Pink areas are crustose coralline algae which is consumed by both species. Orange organisms are an ahermatypic coral Tubastrea sp. Scale bar in (B) is 2.0 cm. The grazed area is a light-colored crescent shaped patch approximately 2.0–3.0 cm wide extending across the upper half of the photograph. These areas were measured as a percent of the substrate grazed by sea urchins in the TC experiments. Also shown are crustose coralline algae (pink), fleshy encrusting algae Hildenbrandia sp. (brown), green algal turf, and diatoms (light brown).