Rocky shores are home to some of the most biologically diverse and productive communities throughout the world. These ecosystems lie at the interface between the land and the sea, exposing organisms here to alternating terrestrial and marine habitats in rhythm with the tidal cycle. When the tide is in, species are bathed by seawater that exposes them to ocean predators, moderates temperatures, delivers food, transports propagules, and imposes large hydrodynamic forces. When the tide is out, the same rocky-shore species are subjected to terrestrial predators, desiccation, temperature extremes, intense solar radiation, and occasional dousing by freshwater.
On rocky shores, invertebrates and algae live in horizontal zones between the high and low tide marks. The zones reflect the varying abilities of species to tolerate the environmental conditions, predation, and competitive pressures at different heights. Intertidal organisms must survive in both terrestrial and marine worlds, transitioning as often as twice each day with the tides. Despite this apparent adversity, rocky shores are home to a striking diversity of species.
Rocky shores have become a favorite testing ground and experimental ‘laboratory’ for ecologists worldwide. Thanks to their steep environmental gradient and the rapid turnover of their abundant sessile or slow-moving organisms, wave swept rocky shores make it practical for ecologists to conduct experiments that would be difficult or impossible elsewhere. Much of what we know about the ecological importance of processes such as competition, recruitment, predation, and patch dynamics has been tested on rocky shores.
Although rocky shores are a comparatively minor habitat on Earth in terms of area, they have played a disproportionately large role in our understanding of ecological systems. As we move into an era of accelerated global climate change and increasing human pressures, the extensive past work in the intertidal zone may serve as a valuable baseline against which to measure the effects of environmental shifts.
PISCO’s research focus on rocky shore habitats reflects their ecological and scientific importance along the coastal region of the California current ecosystem. We continue to monitor biologically important variables such as population replenishment, community structure and biodiversity as well as physically relevant parameters such as organism body temperatures, submersion times and wave forces in an effort to characterize the importance of processes driving the structure and function of these ecosystems and how they may be affected by changing climate conditions.