INFLUENCES OF REMNANT SIZE, SPACING PATTERN AND CONNECTIVITY ON POPULATION-BOUNDARIES AND DEMOGRAPHY IN EUROS MACROPUS-ROBUSTUS LIVING IN A FRAGMENTED LANDSCAPE

In the 14 million ha wheatbelt of Western Australia, depending on location, only 1.7% to 12.5% of native vegetation remains in fragments mostly <30 ha in size. The home range behaviour of the euro Macropus robustus, a large kangaroo, living in this fragmented landscape was examined using radio-telemetry to study movement, and population demography to assess long-term survival prospects. Most euros living in a very large (1196 ha) patch of remnant vegetation were sedentary and did not use any other remnants. However, some young males from this remnant dispersed up to 18 km to other remnants. In areas which had a large remnant (>100 ha), individuals were also sedentary. Some individuals included smaller remnants within 700 m in their home ranges, usually moving along connecting corridors between remnants. Occasionally, a few individuals made excursions of several km outside their normal home ranges either overnight or over several months. In areas where all remnants were small (<30 ha), individuals lived alone or in small groups, moving frequently between several remnants. Overall, the euros in the 1680-kM2 study area appear to be separated into a number of metapopulations, some of which have very small numbers of animals. Within the metapopulations, movements between populations appear to be dependent on the availability of 'stepping stones' and corridors. In two populations which had low densities of euros, the numbers of juveniles per adult female were significantly lower than in systems with higher densities. Long-term survival of these two populations is questionable.