Exposure to wave action: Measurements of an important ecological parameter on rocky shores on Anglesey

Abstract The ways in which the fauna and flora of rocky shores may be affected by wave action are discussed and a simple dynamometer is described by means of which a series of readings has been obtained in a bay on the west coast of Anglesey. These readings have been compared with theoretical values for the maximum dynamic pressure produced by the waves concerned; their agreement shows that such dynamometers are a satisfactory indication of the severity of wave action. The maximum readings obtained have been correlated with the distribution of plants and animals at the same stations. It appears that the typical sheltered shore is very much restricted to the lowest values on the dynamometer scale and that there is a very wide range of values corresponding to very exposed conditions. It is believed that these dynamometers give a simple method of comparing the intensity of wave action on different shores: they are easily and cheaply constructed.