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Australia: The Land Where Time Began |
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Australian Plant Communities
– Palaeocene
In the Palaeocene Period the
plant communities of southeast Australia, in areas of
lowland/coastal, and highland, have been interpreted as wet forests
adapted to cope with the long periods of darkness during winter. The
forests are suggested to have been dominated by conifers (Macphail
et al., 1994).
According to Macphail et al.,
in the Palaeocene most species were elements of the
Cretaceous
flora that extended their dominance over the
angiosperms,
especially those species in the niche of freshwater-swamp habitat. In
the Danian the diversity and abundance of the angiosperms increased, and
in the Bassian region
the ‘ancestral’
Nothofagus spp.
become dominant on a local scale during the latest part of the
Thanetian. There are not many taxa having well-defined affinities to the
mesotherms-megatherms. Though
they all originated in the region of Gondwana some evolved within the
region while others migrated into the region.
At this time it appears that a mesothermal
rainforest vegetation,
that was more varied and variable was present in inland Australia, as
suggested by fossil finds from the
Lake Eyre Basin. Present
in this vegetation were Cunoniaceae and/or Proteaceae. In this
vegetation
Nothofagus was not the
most prominent of angiosperms. The dominance of gymnosperms is linked to
environments of freshwater lakes or swamps, as occurred in southeast
Australia, but there are different taxa comprising the vegetation.
Lygistepollenites balmei,
that is consistently rare, other taxa, such as
Cupressaceae/Taxodiaceae,
are sporadically abundant.
According to Macphail et al.,
deposits at Ninetyeast Ridge has produced pollen that suggests both
northern and western Australia had a vegetation in which many of the
genera were shared with
eastern Australia, though it is not known whether the forest communities
of northern and western Australia were dominated by gymnosperms or
angiosperms.
1.
Macphail, M.K., in Hill, Robert S.,
(ed.), 1994, History of the Australian Vegetation, Cambridge
University Press.
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |