EEP Crowned pigeon number 4

EEP STUDBOOK CROWNED PIGEONS
But for example all passerine and the remaining non-passerine taxa are almost certainly
derived from Asian colonists to New Guinea and Australia. A conclusion based on the
relatively more modern fossil history of these groups or their close phylogenetic ties with taxa
in Australia, or both (Pratt, 1981). A number of boundaries have been placed on
biogeographic maps of the region to try and indicate, for instance, the most western boundary
of the truly Australasian fauna and flora (Wallace’s Line) or the border of shallow sea to the
west of New Guinea (Lydekker’s Line). The first scientist to have studied the phenomenon
was Alfred Russell Wallace in the late 19 th century and, in his honour, the region of faunal
mixing between Wallace’s Line and Lydekker’s Line is sometimes called ‘Wallacea’
(Menzies, 1991).
At the edge of the two plates, New Guinea is tectonically active, with a considerable history
of mountain-uplift, volcanic activity, and earthquakes. Today this is a still continuing proces
(Beehler, et al., 1986) and in 1995, Madang, a city on the northcoast of Papua New Guinea,
was almost completely destroyed by an earthquake.
Many aspects of New Guinea’s topography indicate geological youth: ungraded rivers, Vshaped
valleys, waterfalls, cliffs, and frequent land slippage. This unstable topography makes
road building difficult and frustrates regional development. The island is highly mountainous,
with 66 percent of the land more than 300m above sea level, and 14 percent higher than 1,500
m (Beehler, et al., 1986).
In New Guinea several different geographical subregions can be distinguished, each with
some characteristic flora and fauna. The region which is most obviously different from the
rest of New Guinea is the southern woodland or savanna country, which includes many
elements of the Australian fauna. This region includes the plains of the southern Fly and
Digul Rivers, a narrow coastal strip east and west of Port Moresby and some scattered patches
on the southeast coasts. The animals found here are all common in North Queensland
(Australia) and their presence in New Guinea is a relic of the time when Australia and New
Guinea were one land mass, before the Torres Strait was formed. Relatively a few species are
found in both savanna and forest.
Most of the rest of New Guinea is covered by a tropical rain forest of various species and can
be divided into different zones, the exact boundaries of which vary from place to place
according to local climate and topography. Lowland forest from sea level to about 600m is
often struck by inundation. Hill forests on slopes up to 1000 or 1200 m have a similar
composition but are not struck by inundation in wet weather. Lower montane forest (1200 to
2000m), mid-montane forest (2000-3000m) and upper montane forest above 3000m follows,
but upper montane forests tend to occur in patches interspersed with open vegetation of grass,
sedges and shrubs. With increasing altitude the forest patches and the trees themselves
become smaller and smaller and finally peter out about 3900m.
Lowland and hill forests are further subdivided into northern and southern regions because the
central mountain chain which runs from one end of the island to the other forms a barrier as
there are no low altitude passes from north to south (Beehler, et al., 1986). These zones each
have some characteristic animals, while other animals are widespread through several zones
(Menzies, 1991).
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