Anthropogenic Threats on Intertidal Rocky Shores: Impacts of Global and Local Stressors

Abstract

Within marine environments, intertidal habitats are unique in that they are periodically exposed to air during ebb tides and submerged during flood tides. In rocky intertidal areas anthropogenic disturbances (i.e. any source of stress to natural populations and assemblages due to human activities) are major processes that can determine the distribution and abundance of the species that form communities. Attempting to classify the human activities that can affect rocky shores is a truly complicated task, due to the scale at which they can occur, their intensity, or frequency. In addition, the location of these environments at the land-sea interface and the large number of stressors affecting them, often leads to strong biodiversity changes in this ecosystem. This chapter begins with a general description of rocky intertidal environments, their main characteristics, typical biodiversity, and the ecological processes that structure their benthic communities. Next, the effects of several anthropogenic stressors are described and discussed individually. Examples are provided in order to illustrate how they affect the communities and their structural processes Finally, a description of two contrasting rocky shore environments, South Western Atlantic Patagonia and North Western Iberian Peninsula, is provided with the presentation of study cases for these locations.