Lichina pygmaea failed to recolonize areas cleared from within the lichen ‘mats’ after four years. A retrogression of the lichen was observed in some instances over periods of 5–7 years. A complex of factors governs the size reached by a lichen tuft; more rapid growth occurs in regions where there is some moisture retention during tidal periods. Although changes occurred with individual ‘patches’ of lichen, the total Lichina cover on a rocky surface remained much the same over a 7-year period.