Biogeography of the California Marine Algae with Emphasis on the Southern California Islands

The biogeographical patterns of the marine algal flora of California have received little attention since the classical studies by Setchell (1893, 1917, 1935). This has been due in part to a lack of adequate floristic records, a long-standing obstacle (see Svedelius 1924) to advances in understanding worldwide distributions of marine algae. In the past, as indicated by Hayden and Dolan (1976), coastal marine faunistic patterns have served to delineate biogeographical provinces. Unfortunately, most of the previous distributional analyses have considered only the biota and quantitative attempts to define the physical factors controlling biological patterns have been unsuccessful. Of the physical parameters hypothesized to determine or strongly influence species distributions, temperature has been proposed most frequently as being of greatest importance (e.g., Ekman 1953, Hedgpeth 1957, Briggs 1974). Setchell (1893, 1915, 1917, 1920a, 1920b, 1935), in a series of papers, attempted to explain the global distributions of marine algae, particularly the Laminariaceae, on the basis of temperature. More recently, Abbott and North (1972) discussed temperature influences on the California coastal flora in an effort to advance our understanding of the effects of thermal discharges. However, attempts to statistically correlate temperature with biogeographical patterns have been unsuccessful due to difficulties in selecting an appropriate single "temperature factor" (see Valentine 1966)....