Fig. 2.

Patterns of correlations between annual species replacement patterns at 1,726 fixed points in space and annual average pH during the year. (A) Matrix of correlations between average annual pH and transitions from the starting ecological state (columns) to the ecological state in the following year (rows), scaled by color for correlation coefficients ranging from 1 (bright red) to −1 (bright blue). Ecological states used in transition analysis (grouped by presence of a calcareous skeleton): B-big Mytilus californianus, BG-Balanus glandula, CV-Corallina vancouveriensis, HAL-Halosaccion glandiforme, MT-Mytilus trossulus, PP-Pollicipes polymerus, SC-Semibalanus cariosus, SMC-small Mytilus californianus, FILR-filamentous Rhodophytes, FLR-foliose Rhodophytes, FLC-fleshy crustose algae, R-rock and diatoms, EA-ephemeral algae (Porphyra and Ulva spp.), and OTH-other rare sessile species. Taxa with calcareous skeletons or shells indicated in italics. OTH category includes both calcareous and non-calcareous species. (B) Average correlation between average annual pH and annual transitions from a target species to another species (“From”), from another species to a target species (“To”), or the probability that a target taxon remains at a point in the following year (“Self”), as a function of whether the target taxon has a calcareous skeleton (□) or not (■).