Complex interactions in a rapidly changing world: responses of rocky shore communities to recent climate change

Abstract

Warming of the planet has accelerated in recent years and is predicted to continue overthe next 50 to 100 yr. Evidence of responses to present warming in marine ecosystems include shiftsin the geographic range of species as well as in the composition of pelagic and demersal fish, benthicand intertidal assemblages. Here we provide a review of the changes in geographic distributions andpopulation abundance of species detected on rocky shores of the NE Atlantic over the last 60 yr. Thisperiod encompassed the warm 1950s, a colder period between 1963 and the late 1980s and the recentperiod of accelerating warming to levels above those of the 1950s. The likely consequences of theseresponses are then explored. To do this, a summary of the dynamic balance between grazers,macroalgae and barnacles in structuring mid-shore communities is given before outlining experimentalwork on interactions between key components of rocky shore communities. Modelling andquantitative forecasting were used to predict changes in community composition and dynamics in awarmer world and their consequences for ecosystem functioning discussed. We then identify areasthat need further work before making a case for the use of rocky shore species not just as inexpensiveindicators of change offshore, but as tractable models to explore the direct and indirect effects ofclimate change in marine and coastal ecosystems. We also provide a societal perspective emphasisingthe value of long-term studies in informing adaptation to climate change