Population fluctuations of the New Holland mouse Pseudomys novaehollandiae at Wilson's Promontory National Park, Victoria.

Abstract

The New Holland mouse (Pseudomys novaehollandiae) was first recorded at Wilson’s Promontory in 1972 in heathland vegetation, but has not been located in this habitat subsequently. The species was not trapped again until 1993 when it was found in calcarenite dune woodland on the Yanakie Isthmus. The aims of this study were to assess the population dynamics and habitat use of the species in this dune habitat. Mark-recapture trapping was conducted at three sites from 1999 to 2002. One site was located on low (0 - 5 m), flat sand dunes and open swales, another on medium (5 – 10 m) vegetated dunes, and the third on high (20 m) steep vegetated dunes. The three sites had not been burnt for 30 to 50 years. The abundance of P. novaehollandiae was related to understorey vegetation density and differences in population densities on the sites are likely to be related to the primary succession stages on the sand dunes, rather than fire history. The maximum density (24 ha-1) recorded at one site was very high compared to other Victorian populations, however this was followed by a substantial decline in numbers within the year. At another site a small population declined to extinction. Populations on the isthmus are thus capable of achieving high densities but may decline quickly. Rainfall patterns may have affected the population fluctuations, but further research is required to elucidate fully the factors involved in the long-term dynamics of this species.