Northern Australian Monsoon Vine Forest

Confined to northern Australia, these forests typically occur as small, widely separated stands but extent from the islands off the northern coast, such as Melville Island, through parts of Arnhem Land and Kimberly and nearly as far south as Tennant Creek. However, these are probably remnants of once more widely distributed forests that occurred during former wetter periods, while today they are mainly found around lowland springs, wet escarpments and wet sandstone plateaus. Aboriginal burning may also have influenced their distribution. Their canopies can reach 30 m in places and buttressing is common. The canopy species are mostly evergreen but composition varies from site to site but depending on location the following species may be encountered: Acacia auriculiformis, Buchanania arborescens, Callophyllum sil, Endospermum medullosum, Euodia elleryana, Horsfieldia australiana, Syzygium operculatum, Xanthostemon eucalyptoides and the endemic Allosyncarpia ternata (Myrtaceae), Ilex arnhemicus (Aquifoliaceae) and Syzygium angophoroides (Myrtaceae). There may also be a number of important deciduous elements such as Gmelina dalrympleana, Nauclea orientalis, Terminalia sericocarpa and the endemic Vavaea australiana (Meliaceae). Palms may also be important particularly Livistona benthamii and the endemic Carpentaria acuminara (Arecaceae). However, in places Allosyncarpia ternata can become the sole dominant canopy species. This species is restricted to west Arnham Land but where it does dominate it can have a major controlling influence on the sub canopy microclimate. In general the understories are largely composed of saplings and shrubs such as Alyxia ruscifolia, Boronia lanceolata, Bridelia tomentosa, Melastoma malabathricum and the endemic Coelospermum reticulatum (Rubiaceae). Ground cover, on the other hand, is usually sparse, but in places ferns such as Acrostichum aureum, Blechnum indicum and Lindsaea ensifolia are abundant. Lianas, such as Flagellaria indica and Smilax australis, are common but rarely thicker than a few centimetres in diameter. Epiphytes are largely absent with only a few epiphytic orchids and virtually no epiphytic ferns. This is thought to be due to the long dry season and the general lack of humidity. An interesting feature of these forests is the level of diversity at higher taxonomic levels. In total there are about 95 families and 250 genera covering just 358 species. This is also a feature of rainforest in Queensland.

 

Northern Australian Adansonia gregorii Woodlands

The endemic baobab Adansonia gregorii is largely confined to the Kimberley region. Outside Australia one species of the genus is found in Africa and several in Madagascar, which suggests these represent Gondwanan relicts. However, the Australian species appears most closely related to the African species (Adansonia digitata). They have a similar growth form to the bottle trees (Brachychiton) of eastern Australia but are not related. Common associates include Bauhinia cunninghamii, Buchanania obovata, Celtis philippenensis, Cochlospermum fraseri, Ficus opposita, Gyrocarpus americanus and Terminalia canescens. The ground layer is typically grass dominated mainly by species of Chysopogon and Plectrachne.

Further information required.

 

References

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