BIOL10001 Lecture Notes - Lecture 3: Wallacea, Atherton Tableland, Wallace Line
30 Jul 2018
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LECTURE THREE
Importance of Australian rainforests
Surviving remnants of Gondwanan flora and fauna.
Provide a glimpse back in time to vegetation of Gondwana.
High conservation value, NE Queensland Wet Tropics World heritage area.
Species rich - 50% Australian ferns in rainforests.
13 of the most primitive flowering plant families.
Austrobaileya - pollen similar to oldest angiosperm fossils (120 million years old).
Animals with primitive features.
Austrobaileya
Genus of 1 species (A. scandens).
Usually placed in its own family (Austobaileyaceae).
Has pollen similar to oldest angiosperm fossils (120 million years old).
Placed in own family of plants.
Features useful in understanding angiosperm fossils.
No close living relatives.
Able to look at genome structure.
Types of rainforests
(1) Tropical rainforests
- Occur in North Queensland.
- The structure of a tropical rainforest is complex with a number of vertical layers,
including emergent trees. Little light reaches the forest floor and many plants are
epiphytes or lianes (vines).
- Lowland - most species rich.
- 100-200 tree species per hectare.
- 1000 beetle species per tree.
- Many ferns and palms.
- Trees with large leaves - mesophylls (>12.5 cm) e.g. Daintree, NE Qld.
- At least three storeys of trees forming an uneven, non-uniform canopy.
- Many different tree species contributing to the canopy.
- Predominance of large, often compound leaves with drip tips that drain water off the
leaf so preventing lichens and liverworts growing on them.
- Thick woody vines which interlace the overlapping crowns of rainforest trees.
- Plank buttresses which provide support for the trees in shallow soils.
- High density and diversity of large vascular epiphytes, such as orchids, aroids and ferns.
Epiphytes depend on other plants for physical support, but collect their moisture and
nutrients from the surrounding air and litter that they collect.
- Massed flowers and fruits produced directly on the trunk of many trees, an arrangement
known as cauliflory or stem flowering.
- Plants such as palms, strangler figs, lawyer vines, large-leaved epiphytic climbers and
large-leaved ground herbs.
(2) Cool temperate rainforests
- One quarter of Australia’s rainforests, stretching from the McPherson Range on the New
South Wales-Queensland border to Tasmania, are classed as Cool-temperate.
- Structurally simpler than Warm-temperate Rainforests, these silent, usually damp
forests favour high altitudes, cooler climates and very high rainfall.
- Simple structure, often with only one species in the upper canopy and few species in the
lower layer.
- Small average leaf size of trees. Leaves are simple and feature toothed margins.
- Palms and stranglers absent.
- Buttresses are absent, but the bases of trees are sometimes massive.
- Tree ferns, ground ferns and ‘mossy’ epiphytes common and obvious.
(3) Warm temperate rainforests
- Compared with Tropical and Subtropical Rainforests, Warm-temperate Rainforests grow
at higher altitudes, in cooler climates and on less fertile soils.
- They occur from northern Queensland’s Atherton Tableland to eastern Victoria’s
Gippsland.
- The key features of Warm-temperate Rainforests are order and uniformity. The most
characteristic species of these rainforests are Coachwood.
Document Summary
Provide a glimpse back in time to vegetation of gondwana. High conservation value, ne queensland wet tropics world heritage area. Species rich - 50% australian ferns in rainforests. 13 of the most primitive flowering plant families. Austrobaileya - pollen similar to oldest angiosperm fossils (120 million years old). Has pollen similar to oldest angiosperm fossils (120 million years old). The structure of a tropical rainforest is complex with a number of vertical layers, including emergent trees. Little light reaches the forest floor and many plants are epiphytes or lianes (vines). Trees with large leaves - mesophylls (>12. 5 cm) e. g. daintree, ne qld. At least three storeys of trees forming an uneven, non-uniform canopy. Many different tree species contributing to the canopy. Predominance of large, often compound leaves with drip tips that drain water off the leaf so preventing lichens and liverworts growing on them. Thick woody vines which interlace the overlapping crowns of rainforest trees.
