Do European rabbits (Oryctolagus cuniculus) influence the population ecology of the burrowing bettong (Bettongia lesueur)?

Abstract

The influence of the European rabbit (Oryctolagus cuniculus) on the survival of medium-sized native mammals remains unclear despite 60 years of speculation. Most medium-sized native species that might have been affected by the presence of rabbits are extinct, rare, or endangered. This limits the opportunity to study their interaction with introduced herbivores. We studied the effect of changes in rabbit density on aspects of the ecology of burrowing bettongs (Bettongia lesueur) reintroduced to mainland Australia on Heirisson Prong, Shark Bay, Western Australia. The rabbit population at the site grew to a 10-year high concomitant with a dry summer and low and declining pasture cover. Rabbit browsing led to widespread defoliation of, and subsequent death of, many palatable shrubs. Despite these adverse conditions, reproduction, recruitment and rate of increase of bettongs did not vary with changes in rabbit density, nor did the survival of adult males and females. This work casts doubt on the idea that competition with an introduced herbivore, such as the rabbit, was an important factor in the decline of the burrowing bettong. It highlights the need to understand the ecologies and life histories of native and introduced species in order to manage for the long-term persistence of native species.