Implications of rabbit haemorrhagic disease for the short-term recovery of semi-arid woodland communities in north-west Victoria

Abstract

As part of the National RHD Monitoring and Surveillance Program, an investigation was conducted into the implications of reduced rabbit abundance (as a consequence of rabbit haemorrhagic disease, RHD) for the recovery of degraded woodlands in the Hattah area of north-west Victoria. Both structural and floristic changes were assessed within woodland communities, which are at risk after 140 years of intensive grazing. General recovery in the pasture layer was demonstrated in terms of the improved status of 'decreaser' plant response groups — palatable species. 'Increasers' (weeds) were also found to have benefited in some circumstances but not to the same extent as the decreaser groups. Evidence of structural changes was restricted to increased persistence of sucker regrowth, particularly of cattle bush (Alectryon oleifolius subsp. canescens). No evidence was found of widespread germination of woody seedlings, which is not surprising given the episodic nature of such regeneration events. The interaction of grazers was also investigated by means of a network of grazing exclosures. Less floristic benefit was associated with relatively high kangaroo densities at one location and with stock grazing at another.