Northern Bettong, Betongia tropica Wakefield, 1967

Researchers: Karl Vernes and Lisa Pope

Introduction to the Northern Bettong

The northern bettong is a small (1.2 kg) Potoroid (this group is otherwise known as rat-kangaroos), which is restricted to some areas of mixed open Eucalyptus woodland and Allocasuarina forest bordering rainforest in far northeastern Queensland, Australia.

Northern bettongs are generally solitary animals, and are active only at night. They spend the day in a well concealed nest constructed beneath either a grass tree (Xanthorrea johnsonii), within a clump of grass or from other litter collected at ground level. Nesting material is carried using their prehensile tail. Ectomycorrhizal fungal sporocarps (or 'truffles') are the staple diet of the northern bettong (see left for example). These are dug from beneath the soil at the bases of trees, and work to date suggests that substantial nightly movements are often required to detect this patchily distributed food source. Other foods in the diet include grass roots and tubers, lilies, herbs and sedges. Northern bettongs appear to breed all year round, and like other kangaroos the young is carried in a pouch until it is old enough to follow the mother as a 'young-at-foot'.

Status

The northern bettong is currently listed as endangered on the ANZECC list of Endangered and Vulnerable Vertebrates. It is presently known only from three small isolated populations in far north Queensland, all within 80 km of one other. Reasons for its endangered species status include this restricted geographical distribution, recent contractions in the historical distribution, as well as overall low population densities and the potential threat imposed by feral cats and foxes. The impact of cattle grazing and different fire regimes on northern bettong ecology are also currently poorly understood.

Current Research

Two PhD projects examining different aspects of the ecology of the northern bettongs are currently in progress within the Department of Zoology at James Cook University. The first of these projects (Karl Vernes) looks at the diet, home range and habitat use by northern bettongs and how these aspects of the animals ecology is influenced by fire within its environment. This study involves the use of radio-telemetry to examine home range, microscopic (faecal) and chemical (stable isotope) analyses to examine diet, censusing of bettong diggings along transects and spool-and-line tracking to monitor foraging activity, and the use of prescribed burns to manipulate fire within the forests and woodlands inhabited by bettongs.

The second project (Lisa Pope) is examining the population genetics and mating system of the northern bettong. Micro-satellite DNA fingerprinting is being used to determine the paternity of bettong pouch young. In addition, radio-telemetry is being used to locate bettong nests and to examine bettong home range overlap. The use of both DNA fingerprinting and range overlap should provide a strong indication of the mating system operating within the species, which is relevant for future captive breeding programs. This project is also expected to provide important information about genetic diversity within and between populations of Bettongia tropica.

Both projects began mid 1994 and are expected to run for 3-4 years.

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