Functional traits of species are those that determine either species-specific responses to environmental conditions or their influence on ecological processes. Current theory suggests that communities with many species that perform a given function in a similar way but have different sensitivities to environmental conditions will exhibit greater temporal stability of ecosystem properties. So-called functional redundancy should lead to compensation among species, as some will do better when others do worse in response to environmental variability. Anthropogenic global warming is a major driver of current and anticipated changes in population dynamics, species interactions, and community structure from local to global scales. Resulting changes in biodiversity therefore have the potential to significantly alter important ecosystem properties such as productivity, nutrient cycling, and resistance to disturbance or invasion. Although ecologists have typically emphasized the response of populations and communities to changing climatic averages (e.g., increasing temperature and rainfall), global circulation models also predict significant increases in the intensity, frequency and duration of extreme weather and climate events in many parts of the world; that is, increases in the variability of the physical environment. Unfortunately, our current knowledge about the effects of increasing climatic variation on natural ecosystems is generally quite poor. Predicting how communities will likely respond to changing environmental variability has therefore been recognized as a critical research priority.
Intellectual Merit This project will advance our understanding of how projected changes in temperature variability will affect the behavior, demography, and interactions of key taxa on rocky shores ? a model system for testing theoretical ecological predictions with field experiments. Environmental temperatures strongly influence the physiology, behavior, and demography of most organisms, and changes in average temperature have already been implicated in geographic range shifts of many species. A novel manipulative technique will be used to test the effects of changes in thermal variability on performance by a guild of congeneric grazing limpets, the productivity of their benthic microalgal food, and the resulting interaction strengths between the two taxa. Energy transfer among trophic levels is a key ecosystem process linked to local food-web support and rates of nutrient cycling. This research will evaluate not only species-specific effects of thermal variability on limpet survival, growth, and grazing activity, but also the potential for functional redundancy among limpet species to maintain that ecosystem function over time as environmental variability increases. Data generated from this study will provide a framework for future investigations of the consequences of climate change in this diverse and productive habitat.
Broader Impacts This project will significantly enhance the infrastructure of research and education at California State University, Long Beach (CSULB) - a minority (Hispanic) serving, predominantly undergraduate institution. At least two master's students and twelve undergraduates from CSULB will participate in this study over the three years of funding. Each student will spend ten weeks living and working during the summer at Hopkins Marine Station, gaining an intensive hands-on research experience. This project will also provide training for a postdoctoral scientist at Stanford University, who will gain research experience and proficiency by actively participating in the development and implementation of all aspects of the proposed study. Both PIs are especially committed to providing research experiences and opportunities to women and minorities traditionally underrepresented in science: one of Denny's current three students is a woman, and of the four undergraduate students working in Allen's lab, three are women and one is a Louis Stokes Alliance for Minority Participation (LSAMP) Research Fellow. The LSAMP program (funded in part by NSF) is designed to increase the quality and quantity of underrepresented students successfully completing science, technology, engineering and mathematics (STEM) baccalaureate degree programs, and to increase the number of students interested in, academically qualified for, and matriculated into programs of graduate study. Denny will use data and insight from this project as part of a week-long "biomechanics module" he teaches annually in an intensive summer field program run by the Ocean Discovery Institute (formerly Aquatic Adventures). This program (also funded in part by NSF) seeks to interest inner-city high school students from San Diego in science, and to provide them with the skills needed to gain access to 4-year colleges.