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.

Damage caused by low-density exotic herbivore populations: the impact of introduced European rabbits on marsupial herbivores and Allocasuarina and Bursaria seedling survival in Australian coastal shrubland

“…In more-productive mesic landscapes these effects have generally been documented only at moderate-high population density (e.g. C3 rabbits ha -1 : Cooke 1988; Leigh et al 1987;Chapuis et al 2004). Possibly the lowest-density record from such areas is that of Davey et al (2006) who recorded rabbit damage to Casuarina glaucophylla seedlings when spotlight transect counts averaged 2.1 rabbits km -1 , although Allcock and Hik (2004) suggest seedling impact within that study was measured where rabbit counts were 5 rabbits km -1 .…”

Disturbance, Diversity, and Invasion: Implications for Conservation

“…Collins and Gibson (1990) have further illustrated how grazing, fire, and small-scale soil disturbance all affect the matrix structure of these grasslands differently, and hence can interact to increase community diversity. Leigh et al (1987) found that rabbit populations increased on burned areas of subalpine vegetation, while Noy-Meir (1988) found that elevated populations of voles had the greatest effects on grasslands where other grazing was minimized. Sykora et al (1990) suggested that fire in Dutch grasslands increased nutrients and thus increased the likelihood of "ruderalization" -increasing dominance by a few grasses leading to a decline in diversity.…”

A critical review of the science underpinning fire management in the high altitude ecosystems of south-eastern Australia

“…exceed 80% four years after fires of either low or high intensity (Leigh et al, 1987;Wahren et al, 1999). Around 40-50 years after fire, most of the original shrub communities appear senescent, with large gaps forming in their canopy (Carr, 1977;Wahren et al, 1994).…”