Intertidal Community Regulation Figure 4. The relationship among recruitment rate, interaction strength and mussel percent cover on the rocks (a) and between recruitment rates (on a log scale) and interaction strength (b). For b, black symbols are R-R sites, blank symbols are R-S sites, circular symbols are South Island east coast sites, triangular symbols are South Island west coast sites, and square symbols are North Island east coast sites. Daily recruitment rates are calculated for August–December 2004 for the North Island and the east coast of the South Island sites, and October 2004– February 2005 for the South Island west coast sites. doi:10.1371/journal.pone.0023958.g004 Figure 5. The relationships between mussel recruitment rates or mussel percent cover and predator abundance. Recruitment is per collector per day on a log scale and predator abundance is per m2 for whelks and per search time for sea stars and fish. Symbol shapes and fills as in Fig. 4. doi:10.1371/journal.pone.0023958.g005 PLoS ONE | www.plosone.org 8 August 2011 | Volume 6 | Issue 8 | e23958