The Effect of Excluding Rabbits from Grassland B (Mesobrometum) in Breckland

Abstract

Contiguous examples of Mesobrometum, (Breckland, England), 1 grazed by rabbits the other ungrazed for between 35 and 60 years, showed (1) 12 more species of higher plants in the grazed and (2) an intimate mixture of species in the grazed area as compared with a patterned structure in the ungrazed. The exclusion of rabbits for 21 years from another area of Mesobrometum, which had been grazed for many decades, showed the change from the intimate mixture to the patterned structure. This pattern was formed by various stages in the life cycle of the dominant Festuca ovina. During the period, there was a fall in the number of species. This was brought about by severe competition with the continuous sward of young even-aged fescue in the early stages of the vegetational change. The drop in the number of species inside the enclosure as compared with the greater number in the area ungrazed for between 35 and 60 years is explained by the difference in the initial biotic potentials.