Data from: “Biogeographical Studies of Rocky Shores near Point Conception, California”

Upon request from a local researcher, we have transcribed data from a 1985 University of California, Santa Barbara dissertation titled, "Biogeographical Studies of Rocky Shores near Point Conception, California” by Richard Foster Doyle. The subject of Doyle's research was an investigation into the biogeographic boundary between Californian and Oregonian Provinces that was generally understood to be around Point Conception, CA. He stated:

"The prevailing opinion among biogeographers is that the boundary near Pt. Conception is broad and gradual, extending two to five degrees of latitude. I collected gastropods, algae, barnacles, chitons, and anemones from rocky shores at 40 study sites, located along nearly 400 km of coastline around Pt. Conception. I found 21 species whose ranges reportedly ended in the study area. The range boundaries of these species were highly aggregated near Pt. Conception: 11 fell within 10 km of coast extending east (downcoast) from Pt. Conception. A broad "Transition Zone" between provinces is usually attributed to gradients that do not adequately explain the small size of the distributional break indicated by this study. There is evidence that this narrow transition zone coincides with a convergence of coastal water masses. It is unclear whether littoral species indicate the physiological and biological characteristics of the converging waters, their motions, or both." (p. vi-vii)

Regardless of more recent biogeographic research or any specific interest in this topic, the species distributions found in Doyle's study offer an excellent temporal benchmark for the intertidal species he identified in the early 1980s. Transcribed data include gastropods and algae. Descriptions of barnacles, chitons, and anemones are in the text (not included here). See the ReadMe file for more information.