This study investigated the population dynamics of three species of dasyurid
marsupials in sand ridge habitat of the Simpson Desert, western Queensland,
over a 10-year period between March 1990 and December 1999. The lesser
hairy-footed dunnart (Sminthopsis youngsoni), was
captured most consistently over the period of study, followed by the wongai
ningaui (Ningaui ridei), and the mulgara
(Dasycercus cristicauda). Rates of recapture were low
(4.5–22.2%), probably because individuals of each species are
very mobile. All species bred in late winter or early spring when animals were
aged at least 8–10 months, and independent juveniles first appeared
usually in summer. S. youngsoni reared a second litter
in late spring or early summer in 3 of the 10 years studied, when the
availability of food was likely to have been high; neither
N. ridei nor D. cristicauda were
known to attempt a second litter within a season.
To explore factors that might influence population dynamics, we compared
capture rates of each species with measures of rainfall, temperature,
vegetation cover, abundance of predators [feral cats
(Felis catus), red foxes
(Vulpes vulpes), and goannas
(Varanus spp.)], dragons, other dasyurids and
indices of food abundance. The abundance of S. youngsoni appeared to depend
primarily on the cover of spinifex 7–9 months earlier, that of
D. cristicauda was related most strongly to rainfall
7–9 months earlier, while that of N. ridei was
related to minimum temperature lagged by 1–3 months.
While the dynamics of other arid-zone mammals are driven demonstrably by
interactions between rainfall, resource availability and predation, our
findings suggest that dasyurids have limited flexibility in their life
histories and are influenced more subtly and by factors such as facilitation
that are just beginning to become apparent.
Mapping flood events using remote sensing in an arid zone river, central Australia
