Experimental demonstration of a trophic cascade in the Galápagos rocky subtidal: Effects of consumer identity and behavior - Fig 2

2017-04-21T17:26:05Z (GMT) by Jon D. Witman Franz Smith Mark Novak

(A-B) Pencil urchin (Eucidaris) survivorship and prey selection from tethering experiments. Data points represent the number of surviving small urchins at 1 minute intervals in A-B, and the number of large urchins surviving at 2 min. intervals in C., all from time-lapse photographs. Gray bars below the x-axis in B and C represent night time hours of darkness. Experiments in A were conducted at Rocas Gordon on May 18, 2007 and at Baltra South on May 22 and May 23, 2007, and in B at Isla Champion (January 11, 2008, open triangles) and Rocas Gordon (January 7, 2008 open circles). (C) Survivorship from trials where blunthead and finescale triggerfish consumed the large urchins. The diamond symbols represent a trial initiated on June 27, 2008 while the circles represent a trial begun on July 3, 2008. (D) Average urchin survivorship from two trials of prey selection experiments performed with tethered green urchins (open diamond and triangles) and pencil urchins (black diamond and triangles) placed next to each other on the substrate.