Life at the margins of the continents: an examination of the intertidal marine life of the south Western Cape

Abstract

Imagine surviving in an environment that is neither truly marine nor truly terrestrial. That area just beyond the low-water mark of neap tides along the seashore is an example of just such an environment. The organisms living here have to cope with the combined extremes of both land and sea environments: salt spray, immersion in salt water, emersion in air, drenching by heavy rainfall, heating by the sun, freezing winter temperatures, unstable substrates (such as sand, gravel or boulders), and exposure to strong winds. Just how do they cope? Animals generally find it easier coping in this harsh environment because among other ways, they can simply get up and move when the going gets too tough. Plants (both terrestrial and marine) on the other hand, have to either tolerate, or succumb to it. The following is an account of some of the astonishing ways in which both plants and animals from a typical southwestern Cape shore have evolved to adapt and cope in the harsh environment of the intertidal zone.