Incorporating metapopulation dynamics of greater gliders into reserve design in disturbed landscapes

TABLE 1. Life history parameters of greater gliders used in the
simulation of population dynamics (adapted from Possingham et al.
1994).

Parameter                                 Value

Annual fecundity                          0.25 juvenile females
                                          per adult female
Annual survival rate of juveniles         0.85
Annual survival rate of adults            0.85
Age at maturity                           2 years
Annual risk of fire                       0.01
Mean migration distance of juveniles      2 km
Maximum population density                2 females per ha

BACKGROUND

Biology and ecology of greater gliders

The greater glider is a folivorous, arboreal marsupial that consumes a specialized diet consisting almost exclusively of eucalypt leaves (Marples 1973, Kavanagh and Lambert 1990, Comport et al. 1996). It is a gliding species that is capable of volplaning [greater than]100 m (McKay 1983), and occurs in tall, open eucalypt forests throughout most of eastern Australia (Smith and Winter 1984, Lindenmayer et al. 1990a), except Tasmania (Green 1974). Studies of aspects of the biology and ecology of Victorian populations of the greater glider have been completed by Henry (1984, 1985) and Lindenmayer et al. (1990a). Other investigations of the species in southeastern Australia include those by Smith (1969), Tyndale-Biscoe and Smith (1969a, b), Robinson (1984), Kavanagh (1987), Lunney (1987), and Norton (1988). Results of these studies have been used to develop a set of life history parameters for input to our model (Table 1). Attributes from Victorian populations of the greater glider were used to construct this parameter set wherever possible. With the exception of the migration rates, these values were the same as those used in a modeling study by Possingham et al. (1994). The dynamics of the species were modeled within remnant patches of old-growth forest and adjacent areas of regrowth forest, because other areas are unlikely to provide suitable habitat in the long term (Possingham et al. 1994).

Ada Forest Block

Simulations of greater glider metapopulation dynamics in timber production areas were based on the Ada Forest Block, an area of [approximately]6700 ha in the Central Highlands of Victoria. The Ada Forest Block was targeted for analyses for a range of reasons. First, it enabled comparisons to be made between this investigation and an earlier one of the greater glider in the same area, by Possingham et al. (1994), in which spatial correlation in the disturbance regime was ignored. Second, the size, spatial location, and age of different types of forest (Noble 1977, Smith and Woodgate 1985, McHugh 1991, Griffiths 1992, Lindenmayer et al. 1995b) and the habitat requirements of the greater glider (Lindenmayer et al. 1990a, 1993, 1994, 1995b) are well known in the Ada Forest Block. Finally, Attiwill (1994) considered that the present mix of conservation and wood production strategies in the Ada Forest Block is a "model" for balancing multiple uses such as timber production and wildlife conservation. Our analysis allowed us to test this assertion with respect to the long-term conservation of greater gliders.