1. The Australian continent provides an important test of macroecologi
cal patterns given its unique biota and long-term geographical isolati
on. However, macroecological contributions from the Australian contine
nt are rare. We explored the relationship between abundance and geogra
phical range for Australian frogs (Order Anura) across complete geogra
phical ranges, and investigated how adult body size relates to both ab
undance and the size of geographical ranges. 2. Our analyses followed
two complementary paths. First, we employed cross-species correlations
at a number of taxonomic levels to analyse present-day ecological ass
ociations among the macroecological variables. Secondly, we tested whe
ther there were correlated evolutionary divergences among the variable
s by use of the phylogenetic regression. In the event, cross-species p
atterns and correlated divergence patterns proved quite similar for th
is dataset. 3. For Australian frogs there is a strong, significant pos
itive correlation between abundance and geographical range, that is no
t mediated through body size, and that is found for both cross-species
correlations and as correlated evolutionary divergences. Among biolog
ical mechanisms that have been proposed, some can be rejected. Feasibl
e explanations would invoke resource use or intrinsic rates of increas
e or both. 4. There is also a significant positive correlation between
adult body size and geographical range. We were able to discard four
of the five proposed mechanisms describing this relationship. The rema
ining mechanism relates to homeostasis and environmental variability.
5. Previous studies of the relationship between adult body size and ab
undance have revealed a strong negative correlation when studies are p
erformed over areas that encompass most or all of the geographical ran
ges of the species in question. Contrary to these studies, a negative
relationship was not found for Australian frogs. None of the eight exp
lanations postulated from other studies can account for this discrepan
cy, leading to the conclusion that Australian frogs provide a contrast
to macroecological patterns prevailing elsewhere. 6. Body size could
not explain directly the relationship between abundance and geographic
al range. While there was a significant positive correlation between b
ody size and geographical range, there was no relationship between bod
y size and abundance. If a mechanism incorporating the intrinsic rates
of increase of species is to explain the positive relationship betwee
n abundance and geographical range, then ecological factors other than
body size must be determining differences in intrinsic rates of incre
ase.