PATCH DYNAMICS OF PLANT SUCCESSION ON ABANDONED SURFACE COAL MINES: A CASE HISTORY APPROACH

SUMMARY revegetation in Missouri, U.S.A., is described. (2) The six sites have undulate surfaces and slightly to very acidic spoils. (3) The size and frequency of vegetation patches were measured by computer image-analysis of digital maps prepared from aerial photographs taken at various intervals after the sites were abandoned. (4) Despite differences in the rates of revegetation, the six sites were rapidly colonized by plants which grew to form patches. These patches grew at a uniform rate, while new patches were also formed. Eventually, the patches coalesced and dominated the surface. The degree of non-circularity of patches was at its maximum when fusion of patches became widespread. (5) Grazing of one site reduced total cover and produced a transient fission of patches so that, for a short time, their density increased and non-circularity decreased.