TheBallantine scale is a biologically defined scale for measuring the degree of exposure level of wave action on arocky shore. Devised in 1961 by W. J. Ballantine, then at the zoology department ofQueen Mary College,London, the scale is based on the observation that where shoreline species are concerned "Different species growing on rocky shores require different degrees of protection from certain aspects of the physical environment, of which wave action is often the most important." The species present in thelittoral zone therefore indicate the degree of the shore's exposure.[1]
An abbreviated summary of the scale is given below. The scale runs from 1) an "extremely exposed" shore, to 8) an "extremely sheltered" shore. Thelittoral zone generally is the zone between low and high tides. The supra-littoral is above thebarnacle line.
| Scale unit | Name | Environment | Species |
|---|---|---|---|
| 1 | Extremely exposed | Continuous heavy surf |
|
| 2 | Very exposed | "Workable only on calm days" |
|
| 3 | Exposed | Occasional full Atlantic storm-waves |
|
| 4 | Semi-exposed | Obvious "reduction in wave action" |
|
| 5 | Fairly sheltered | ||
| 6 | Sheltered | ||
| 7 | Very sheltered | ||
| 8 | Extremely sheltered |
A modified exposure scale of five stages applying to the shores of the British Isles is given by Lewis (1964):[2]
