Effects of Rabbit Grazing and Fire on a Sub-Alpine Environment .I. Herbaceous and Shrubby Vegetation

Abstract

The effects upon shrubby and herbaceous vegetation of two low-intensity fires and/or grazing by feral rabbits and wombats were studied in a subalpine environment between 1977 and 1984. Fire reduced shrub cover and biomass to low levels and their recovery was slow. When unburnt, tall shrubs increased, then decreased as a result of extreme frost and drought and subsequently continued to decrease. The recovery of the herb cover and biomass after fire was complete within a year except when delayed by drought andlor disturbance by rabbits. Bare ground was less than 2% in the absence of fire and rabbit grazing but increased to nearly 20% after fire in the presence of rabbits. Rabbits reduced the cover and biomass of 39 species of forb, in some cases to zero. Feral rabbit populations survived and multiplied on burnt areas but decreased on areas left unburnt. The implications of this research for the management of similar environments are discussed.