Bryophyte recolonization of burnt ground with particular reference to Funaria hygrometrica I. Factors affecting the pattern of recolonization

Abstract

Two types of fires were distinguished, rapid fires and bonfires, the amount of ash deposited and the intensity of heating both being greater during a bonfire. Rapid-fire sites are recolonized largely by the pre-burn species, but on bonfire sites, after an initial delay period, in which both angiosperm and bryophyte growth is inhibited, a characteristic bonfire community is formed in which Funaria hygrometrica is the most conspicuous species. Field experiments and soil analyses confirmed that edaphic conditions were of primary importance in determining the establishment of the bonfire community and showed that a major difference between the two sorts of fire lay in their effect on the surface soil.

After a bonfire, high concentrations of soluble organic matter and inorganic nutrients were found. With the exception of the calcium concentrations, these decreased with time, the levels of potassium, magnesium and phosphorus approaching or even reaching those of the unburnt soil after 18 months. It seems very likely that after an initial increase in the levels of both ammonium- and nitrate-nitrogen, the rate of nitrification would be stimulated and remain high for a considerable length of time. Rapid fires, as expected, appeared to have relatively little effect on the surface soil, levels of calcium and phosphorus in particular were never as high as in bonfire soils and it is most unlikely that there was any stimulation of nitrification.