The Carpentarian Rock-rat Zyzomys palatalis is a critically endangered conilurine rodent known from four gorges on Wollogorang Station, in the south east Gulf region of the Northern Territory. The conilurine rodents include many 'old endemic' Australian rodents which have proven highly susceptible to population declines and extinction probably because their low reproductive rate does not allow sufficient population growth under elevated levels of predation (from introduced species) particularly in association with habitat loss or alteration (e.g. grazing and fires) (Smith and Quin 1996). In this thesis, the floristic and environmental relations of Gulf region gorge systems are characterised in detail in Chapter 2 to provide a framework for explaining the patterning of Z.palatalis. The environment of the gulf gorges, as characterised by plant composition and habitat attributes are not unique to this region. The plants are composed of two major groups, both of which are patchily widespread in rocky ranges throughout north western Australia. In the first group I include monsoon rainforest plants (sensu Liddle et al. 1994) and also mesic broadleaf woodland taxa, and the second group includes the sclerophyllous 'arid adapted' woodland taxa such as eucalypts and hummock grass. Although rainforest patches often appear to be discrete there is a floristic continuum from monsoon rainforests to broadleaf woodlands. Monsoon rainforests and broadleafwoodlands are fire-sensitive and are almost entirely restricted to rugged within-gorge habitats. Many of the plants occurring in these communities are widespread because they have similar origins (part of a Gondwanan flora) and / or because of dispersal by animal vectors (Liddle et al. 1994). Large fleshy or woody fruits and seeds were common reproductive structures in the rainforest and broadleafwoodland species and were identified as key food resources for Z.palatalis.
|Date of Award||Dec 1996|
|Supervisor||Richard Noske (Supervisor) & John Woinarski (Supervisor)|