Australia: The Land Where Time Began

A biography of the Australian continent 

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.

Sources and Further Reading

1.      Macphail, M.K., in Hill, Robert S., (ed.), 1994, History of the Australian Vegetation, Cambridge University Press.