Introduction

Australia has an area of tropical rain forest located in the northeast of Queensland. Frequently referred to as the Wet Tropics, this area contains a range of different rain forest types, including both lowland and montane types. For a long time, these forests were thought to be an extension of Asian rain forests. However, they are now known to have largely evolved independently, and represent the remnants of much more widespread humid forests that used to cover much of Australia.

These forests have large numbers of endemic species that evolved on the Australian continent during its long period of isolation. There has however been some modification as a result of contact with Asia, and some Melanesian elements have successfully colonized Australia. Understanding these forests requires an understanding of the history of the Australian continent, and we discuss this in some detail.

Outcomes

By the end of this topic, you should be able to:

• Describe how the forests of Australia, and the particular the rainforests of northeast Queensland, developed
• Assess how the current Australian flora is dependent on the break-up of Gondwana
• Outline some of the relationships between past floras and today’s plants
• Interpret the dynamic between sclerophyll woodland and rainforest
•  Describe some of the fauna found in Australia’s Wet Tropics
• Explain why so many endemics are present
• Discuss the evolutionary origins of the fauna, comparing the species that have Gondwanan origins with those having Laurasian origins

Readings

Optional Readings

Flora

• Beasley, J. 2006. Plants of tropical North Queensland. The compact guide. Kuranda, Australia: Footloose Publications. 192 pp.
• Groves, R.H. (ed.) 1994. Australian vegetation. Cambridge, Cambridge University Press. 562 pp.
• Hill, R.S. (ed.) 1994. History of the Australian vegetation. Cretaceous to recent. Cambridge, Cambridge University Press. 433 pp.
• White, M.E. 1994. After the greening. The browning of Australia. East Roseville, NSW: Kangaroo Press. 288 pp.
• White M.E. 1998. The greening of Gondwana. The 400 million year story of Australia’s plants. East Roseville, NSW, Australia: Kangaroo Press, 256 pp.

Fauna

• Adam, P. 1992. Australia Rainforests. Oxford, UL: Clarendon Press. 308 pp. Chapter 7.
• Barker, J., Grigg, G.C. and Tyler, M.J. 1995. A Field Guide to Australian Frogs. Chipping Norton, NSW, Australia: Surrey Beatty & Sons. 407 pp.
• Braby, M.F. 2004. The Complete Field Guide to Butterflies of Australia. Collingwood, Vic, Australia: CSIRO Publishing. 339 pp.
• Hangay, G. and Zborowski, P. 2010. A Guide to the Beetles of Australia. Collingwood, Vic, Australia: CSIRO Publishing. 238 pp.
• Menkhorst, P., Rogers, D., Clarke, R., Davies, J., Marsack, P and Franklin, K. 2017. The Australian Bird Guide. Clayton South, Victoria, Australia: CSIRO Publishing. 566 pp.
• Rentz, D. 2010. A Guide to the Katydids of Australia. Collingwood, Vic, Australia: CSIRO Publishing. 214 pp.
• Swanson, S. 2007. Field Guide to Australian Reptiles. Archerfield, Australia: Steve Parrish Publishing. 271 pp.
• Theischinger, G. and Hawking, J. 2006. The Complete Field Guide to Dragonflies of Australia. Collingwood, Vic, Australia: CSIRO Publishing.366 pp.
• Tyler, M.J. and Knight, F. 2009. Field Guide to the Frogs of Australia. Collingwood, Vic, Australia: CSIRO Publishing. 188 pp.
• Van Dyck, S. and Strahan, R. (eds.) 2008. The Mammals of Australia. 3^rd Sydney, Australia: Reed New Holland. 886 pp.
• Wilson, S. and Swan, G. 2003. Reptiles of Australia. Princeton, New Jersey, USA: Princeton University Press.
• Zborowski, P. and Edwards, T. 2007. A Guide to Australian Moths. Collingwood, Vic, Australia: CSIRO Publishing. 214 pp.
• Zborowski, P. and Storey, R. 2003. A Field Guide to Insects in Australia. 2^nd Chatswood, Australia: Reed New Holland. 208 pp.

Fundamental Concepts

This topic contains two presentations, one dealing with the flora of Australia's tropical rain forests and the other dealing with the fauna.

5.1.2a Case Study - The flora of Australia's tropical rain forests.pptx Download 5.1.2a Case Study - The flora of Australia's tropical rain forests.pptx

5.1.2b Case Study - The fauna of Australia's tropical rain forests.pptx Download 5.1.2b Case Study - The fauna of Australia's tropical rain forests.pptx

Self-check Quiz (For certificate learning only)

After viewing topic presentations, take this self-check quiz to check your own progress. This quiz is designed to see how well you remember some of the issues presented in the topic. There are five questions, and each has a potential of 4 answers, only one of which is correct. When you are ready, click the link 'Self-Check Quiz 5.1.2' to start taking the quiz.

Case Study Discussion (For certificate learning only)

Once you have have read the presentation, post a question about the ecology of the rain forests of northeastern Australia, and answer/respond to at least one other student’s question on the discussion board Case Study 2 Discussion - Australia's Tropical Rain Forests.

Summary

The tropical rain forests of northeastern Australia were once thought to be an impoverished extension of the forests of southeast Asia. This is now known to be completely wrong, and they represent a unique type of forest some of which originated in Gondwana and subsequently evolved after Australia's separation. Well-represented Gondwanan families include the Anacardiaceae, Cunoniaceae, Lauraceae, Proteaceae, Rutaceae, Sapindaceae and Symplocaceae. Sixteen of the 28 primitive angiosperm families are also represented in the forests, more than any other tropical rain forest region. Some Malesian species managed to make the eastward crossing over Wallace's Line, and represent a relatively new element in the flora and fauna of Australia.

Detailed phytosociological studies have been undertaken in these forests, making them amongst the best known of any tropical rain forests. Many different types have been recognized, but a broad classification, involving 11 types, can be usefully applied. The forests represent an important component of the overall biodiversity of Australia, containing for example 65% of the ferns and 37% of the conifers found in Australia. The fauna found in the forests is also unusual, and contains groups like the tree-kangaroos that are not found elsewhere in Australia.  

Many questions about the flora and fauna of the Australian tropical rain forests exist. For example, it is unknown why more megabats did not colonize Australia from New Guinea. The history of rain forest mammals remains very uncertain, and the extent of speciation today is unclear. Birds show some striking patterns that remain to be fully explained, such as why endemic species in the Wet Tropics are concentrated in upland forests, and why so few other rain forests in Australia generally lack endemic bird species. These forest offer many opportunities for further research, but are being affected by external factors such as climate change.

Self-review (For self learning)

To review what you have learned in the topic, you are encouraged to use the following reflection questions as a study guide to do a self-review for the topic:

•  How did the forests of Australia develop, and in particular the rainforests of northeast Queensland?
• Why is break-up of Gondwana so important to explanation of the composition of the current Australian flora? 
• How closely related are the past floras of Australia with today’s plants?
• What controls the relative importance of sclerophyll woodland and rainforest?
• What are some of the more unique fauna found in Australia’s Wet Tropics?
• Why are there so many endemics present?
• What are the evolutionary origins of the fauna, and how do species with Gondwanan origins compare with those with Laurasian origins?