Birds of paradise, biogeography and ecology in New Guinea: a review

894 M. Heads
Again, this `discrepancy' or `paradox' has been explained
as resulting from the different means of dispersal (Mayr,
1953), but it seems more likely to be simply because of
different groups having different evolutionary centres;
angiosperms and insects both have major centres in the
Indian Ocean and Paci®c Ocean regions, whereas passerines
and mammals have major centres around the Indian and
Atlantic Oceans.
Figure 1 Distribution of Paradisaeidae, showing areas with ³ 10
species (stippled) and ³ 20 species (black) per 1° ´1° grid cell.
ecology in New Guinea. Some main aspects of distribution in
the birds of paradise are discussed ®rst.
BIOGEOGRAPHY
The major species concentrations in New Guinea of such
distinctive bird families as birds of paradise, bowerbirds
(Ptilonorhynchidae) and cassowaries (Casuariidae) renders
the absence there of major, widespread groups such as
trogons (Trogoniformes) and woodpeckers (Piciformes)
`almost mysterious' (Gilliard, 1969) and certainly worth
investigating. This presence and absence are sometimes
attributed to dispersal into New Guinea, or lack of it,
because of different means of dispersal in the respective taxa.
However, employing the usual concept of dispersal does
leave the patterns rather enigmatic. Instead, it is suggested
that these patterns of replacement are not caused by
`dispersal' as physical movement, but are the result of
vicariant evolution mediated by tectonic processes on prior
landscapes.
Different groups in New Guinea show af®nities with
different parts of the world. For example, plants and insects
there show many connections with Indo-Malaysia and there
are also many trans-tropical-Paci®c groups, whereas the
passerines and mammals show strong Australian connections.
(There are few trans-Paci®c ties in these groups ± the
New Zealand bat family Mystacinidae and South American
taxa, possible af®nities in marsupials, and possible af®nities
between the passerines Acanthisittidae of New Zealand and
suboscines in South America ± and these are in the far
south).
The New Guinea orogen
The birds of paradise are distributed rather evenly throughout
the folded and faulted mountain ranges of the spine of
New Guinea ± the New Guinea orogen (Figs 2, 4 & 29).
This mountainous belt was formerly regarded as the result of
a simple continent±island arc collision, but Pigram & Davies
(1987) gave a radical re-interpretation. They described the
orogen as consisting of a southern part (the Australian
craton), and a northern part made up of at least thirty-two
tectonostratigraphic terranes ± fault-bounded geological
provinces with independent histories from other terranes.
The New Guinea terranes, including intrusive and metamorphic
rocks, formed and sometimes amalgamated with
others some distance from their present position and
subsequently accreted to the craton margin. In the Vogelkop
accretion history involves mainly continental terranes. The
central Kemum terrane was detached from Gondwana by
the early Cretaceous and then had a history of movement
independent of the Australian craton until the Miocene. In
central New Guinea, the Sepik and Rouffaer terranes had
docked with the craton by the Late Oligocene, when the
New Guinea orogeny was initiated. In eastern Papua New
Guinea (PNG) several terranes of diverse origin amalgamated
in the Palaeogene (Early Eocene if this caused the
metamorphism of the proto-Owen Stanley terrane), and this
composite terrane then docked with the Australian craton in
the Miocene. Finally the Finisterre terrane was accreted to
the mainland at 3.0±3.7 Ma (Abbott et al., 1994), and rapid
uplift continues there. Probably New Britain will dock next.
Pigram & Davies (1987) discussed transcurrent movement
Figure 2 Geological map showing the Australian craton (grey), the
New Guinea orogen (between the heavy broken lines), and the
accreted New Guinea terranes (black). Blank areas on the map are
successor basins (simpli®ed from Pigram & Davies, 1987).
Ó Blackwell Science Ltd 2001, Journal of Biogeography, 28, 893±925