Meeting Abstract
Predicting the impacts of climate change on the abundance and distribution of organisms continues to be a focus for scientists and resource managers. For organisms in the intertidal zone of wave-swept rocky shores, temperature is a particularly powerful selective agent which can shape species distributions. In this study, we examine the effects of artificially increased temperatures on the rocky intertidal community adjacent to Hopkins Marine Station in Pacific Grove, California, over a period of twelve years. Rock settlement plates were used in concert with an insulating layer of neoprene to produce temperatures 1-10°C higher than the neighboring bedrock during afternoon low tides. In order to characterize the mature communities, biological surveys were conducted in the final year of the study. The experimental plates displayed decreased percent cover and species-level diversity in comparison to neighboring bedrock, and the communities were characterized by barnacles instead of upper intertidal algae. A mechanistic heat budget model was used with historical environmental data to recreate the minute-to-minute thermal histories of the test plates and the adjacent bedrock. It was found that average cumulative degree minutes over twelve years was negatively correlated with diversity and cover in both communities. This study provides an opportunity to observe long-term shifts in community structure under test conditions which mimic climate pressures, and verifies the potential of mechanistic heat budget models used in concert with environmental data to generate accurate and informative thermal histories.
