Barry et al. [1] compared the abundances of 45 intertidal species at a site near Monterey Bay to a survey done sixty years earlier at the same site and found changes in population to be correlated to rising atmospheric and ocean temperatures. In another survey of the abundances of 12 intertidal species, including A. sola, at 42 sites along the western coast from Mexico to Alaska, Sagarin and Gaines [2] found A. sola to be more abundant in the south than in the north. However, the latter study did not take temperature measurements at the sites and stated that patterns of species abundance would need to be tracked over an extended period of time to gain further insight into changes in intertidal communities. Both studies indicated the need for creating careful baselines for future comparison.

Stillman and Somero [3] and Stillman [4] observed that porcelain crabs living in conditions near the edges of their thermal tolerance range had reduced tolerance to temperature variations. Helmuth, Harley, Halpin, O’Donnell, Hofmann, and Blanchette [5] showed that the duration of exposure to air and ocean can affect the distribution of the mussel Mytilus californianus. The results of these studies suggest that small changes in climate can significantly affect population distributions of intertidal organisms.

The Long-Term Monitoring Project and Experiential Training for Students (LiMPETS) program [6] is conducting a long-term survey of the abundance and distributions of many intertidal communities, including A. sola, along the California coast. However, this survey is not tracking temperature measurements in the intertidal, making it difficult to correlate results with temperature change. Similarly, while the National Oceanic and Atmospheric Administration (NOAA) tracks long-term trends in ocean and atmospheric temperatures [7], its records do not provide data on individual microhabitats in the intertidal. It is therefore important to measure intertidal temperature and species abundance simultaneously to understand how climate change influences population.

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References

1. Barry J.P., Baxter C.H., Sagrin R.D., & Gilman S.E. (1995). Climate-related long-term faunal changes in a California rocky intertidal community, Science 267 (5198): 672-675.
2. Sagarin R.D. & Gaines S.D. (2002). Geographical abundance distributions of coastal invertebrates: Using one-dimensional ranges to test biogeographic hypotheses. Journal of Biogeography 29: 985-997.
3. Stillman J.H. & Somero G.N. (1996). Adaptation to temperature stress and aerial exposure in congeneric species of intertidal porcelain crabs (Genus Petrolisthes): Correlation of physiology, biochemistry and morphology with vertical distribution. Journal of Experimental Biology 199: 1845-1855.
4. Stillman J.H. (2003). Acclimation capacity underlies susceptibility to climate change. Science 301: 65.
5. Helmuth B., Harley C.D.G., Halpin P.M., O’Donnell M., Hofmann G.E., & Blanchette C.A. (2002). Climate change and latitudinal patterns of intertidal thermal stress. Science 298: 1015-1017.
6. Long-Term Monitoring Project and Experiential Training for Students (2004).
7. National Oceanic and Atmospheric Administration. National Buoy Data Center: Monterey Bay to San Francisco Bay