Role of sand in the domination of hard substrata by the intertidal alga Rhodomela larix

Sand movement is a common feature of most coastlines, however its effects on rocky intertidal communities have only recently begun to be examined. This study provides information on the influence of sand on a common intertidal alga that has not been previously described as psammophilous or sand-loving. The red alga Rhodomela larix (Turner) C . Agardh does occur on shores not influenced by sand but was common and frequently very abundant (greater than 50 % cover) at rocky sites along the northwestern coast of the USA with both coarse and fine-grained sand accumulations. Field and laboratory observations suggest that R. larix can survive lengthy anoxic burial and severe sand scour, in some cases better than some of its potential competitors. In addition, potentially damaging herbivores and epiphytes may be negatively affected by sand burial. Thus sandy sites may serve as refuges from competitors, herbivores and epiphytes, resulting in patterns of spatial dominance by R. larix.