A biological review of Pseudomys oralis: a response to Pyke and Read.

Abstract

IN their recent paper, Pyke and Read (2002) provide a detailed review of the biology and ecology of the Hastings River mouse Pseudomys oralis. The authors should be commended for compiling this information, however, there are some comments I would like to make to provide a contemporary review of this species. The authors note there has been no discussion of geographic variation within P. oralis or recognition of a subspecies. However, the recovery plan (NPWS 2003), which has been in draft for many years, emphasises the need to survey populations between the mitochondrial DNA haplotype sites identified by Jerry et al. 1998 to determine whether there are two distinct species. Pyke and Read (2002) also maintain the historical belief that P. oralis is mostly found in open habitat associated with riparian features (gullies and watercourses). Based on the studies of Townley (2000), Keating (2000) and new data collected by Meek (2002) and Meek et al. (2003), there is evidence that P. oralis is not dependent on riparian habitat. The species has been captured at many ridge and mid-slope sites where sedges and/or grasses are not found in high abundance. High numbers of P. oralis trapped and monitored at Marengo State Forest since 2000 have been found living on a ridge top in an open forest habitat dominated by fern (Meek 2002; Meek et al. 2003). Radio tracking and spool-and-line tracking from this forest showed that P. oralis did not favour a microhabitat of grasses or sedges and when riparian habitat was available the tagged animals rarely used it. Habitat at known P. oralis sites indicate that shelter is an important factor in population size, however emphasising the value of rock shelter as an indicator of capture success (Keating 2000) ignores the value of head and butt residue and fallen timber for the species. In all of the trapping sites described in Meek et al. (2003), none contained large amounts of large or small rock. However, occurrence of the species and trap success does correspond with the amount of hollows in fallen timber and residues from previous logging events and is further supported by tracking observations (Meek 2002, 2003).