The intertidal zone has been described as ground zero for global warming. Here, the owl limpet, Lottia gigantea, adapted to the cool ocean temperatures, must withstand a few hours of baking sun during day-time low tides. This hardship is predicted to increase in frequency and severity in the future as the globe warms. Our research hypothesized that heat events compromise territorial behavior of L. gigantea. All observations and experiments were performed at Inspiration Point near Newport Beach, California. We measured the natural radiant temperature of tagged limpets during day-time low tides using a field-calibrated infrared “thermogun”. We also experimentally amplified radiant temperatures of limpets by 7-12°C using mirrors to reflect the sun’s heat. Control limpets were not heated. We then observed the behavior (Territorial, Retreat, or No Response) of the same limpets during high-low tide (0.5-0.6m ) when limpets were washed by the sea. Territorial encounters were staged by using “bait limpets” placed in the path of tested limpets to induce a response. We found that high radiant temperature is correlated with decreased movement, responsiveness, and aggressiveness of limpets. By contrast, experimental evidence of high temperatures reducing territoriality was weak, likely because of the short time span of heat amplification. Lottia gigantea is a bona fide “ecosystem engineer” whose territorial behavior shapes the rocky intertidal community of invertebrates. Our data show that local heat events compromise the territorial behavior of L. gigantea, which may consequently alter the rocky intertidal community.
Gunanto, Tracey; Chavez, Christina; Martinez, Jessica; and Wright, William G., "The Non-Lethal Effects of Climate Change on the Territoriality of Lottia gigantea" (2014). Student Research Day Abstracts and Posters. 3.