Rocky shores are characteristic of areas where sediments have been removed by wave action or currents and as a result leave the bedrock exposed. These shores can comprise a complex mosaic of habitats depending on aspect (vertical, horizontal, overhanging etc.), the degree of exposure to the waves or currents, exposure to sunlight and air. The influence of the latter is particularly obvious in the zonation of tidal shores with a few hardy species surviving at the upper tidal levels but avoiding predation by and competition from species less resistant to desiccation and the most productive zone at the lower limits of the tidal range. Rock pools and gullies at different tidal levels harbour characteristic communities. All species have limits of temperature tolerance and their distribution may change in response to climatic variation. This is particularly the case in species with a planktonic dispersal phase in the life cycle, usually a motile spore stage in algae or larval stage in animals. Barnacles, which have planktonic larvae, are known as good indicators of climatic variation as once they have settled they are immobile.

Rocky shores are not continuous around the coast, and not all components of the mosaic of habitiats are present on all rocky shores and in order for a species to be able to take advantage of new potential habitats they have to be able to bridge the gaps. This is more readily achieved by species with planktonic dispersal phases. Rapid sea level change resulting from the melting of ice caps as well as thermal expansion of seawater may significantly alter habitat distributions due to topographical factors, the changed shapes of the coastline and depth distributions near to the shore, changing the hydrography. It has been suggested that climate change may not lead to a simple poleward shift in the distribution of intertidal organisms on rocky shores but could cause localised extinctions in a series of 'hot-spots' due to the inability of species to spread to suitable habitats.