Australia is the world’s oldest, flattest and driest populated continent, and the main reason for its fantastic landscape and impressive rock formations is its geological stability. But geological processes also produce the soils and so affect the plant life. Here is some information about Australian famous rock formations, red desert soil, Australian desert plants, tropical rainforest plants, temperate rainforest climate, alpine vegetation, and the fact that the flower pollination of most Australian plants is not done by wind or insects, but often by birds and small animals.
Australian Geological Stability Away from tectonic plate boundaries, volcanoes don’t erupt and mountain ranges don’t rise. In great contrast to the neighbouring geologically active New Zealand, Australian continent hasn’t changed, other than eroded, since the uplift of the Great Dividing Range 80 million years ago. This geological stability has given erosion a lot of time to expose some of the world's oldest and most amazing rock formations, like Twelve Apostles in Victoria, Remarkable Rocks and Murphy’s Haystacks in South Australia, pinnacles in Nambung national park and the Wave Rock in Western Australia; and Devil’s Marbles, Kata Tjuta and the world’s largest monolith Uluru in Uluru Kata Tjuta National Park in the Northern Territory.
Australian Red Desert Soil These fantastic rock formations are often surrounded by the reddest soils you are likely to ever have seen. It’s so beautiful and it makes the whole landscape so colourful, particularly when the sun sets. So why is it? Why is it that in Europe the soils are black and in Australia they are red? I know it’s not fair but it’s because of the climate. Soil is the product of rock erosion, and the erosion is caused by weathering. In cold climate, like in Europe and most of the North America, the main form of weathering is physical, such as jointing, frost wedging, and in places the impact of ancient glaciers. In hot climate like in Australia and in south-eastern USA, the weathering is chemical. Reactions like hydrolysis, hydration and oxidation happen – and the red colour is a result of oxidation, more exactly – iron oxides, just like rust.
Australian Plants' Adaptations Where there is no geological activity, there is no formation of new fertile soils, instead the old soil is leached and blown away, leaving plants with little chance to fasten their roots. The climate doesn’t help the situation - depending on the stage of El Niňo – La Niňa cycle, Australia either suffers from floods or droughts. These harsh conditions have forced plants to develop canny adaptations to balance on a bare rock wall or develop long roots to survive in a lifeless desert.
Courtesy of Tourism Northern Territory
Australian Plants in the Tropical Rainforest Australia broke off the other Gondwana continents 55 million years ago and has since been drifting northwards. Its north lies now in tropics and supports tropical rainforests – some of the species-richest ecosystems in the world, with hundreds of species of tropical rainforest plants like tall trees, vines, epiphytes; and a lot of species of tropical rainforest animals. Conditions important for plant life - water, heat and light - are at the best of all biomes on the earth. Most of species thrive really well although there are some endangered species amongst Australian rainforest animals.
Australian Plants in Temperate Rainforest Climate Not all rainforests are tropical. In southwestern Tasmania and eastern highlands, there are pockets of temperate rainforests with temperate rainforest plants like beech trees, the amazing cycads and ferns; and temperate rainforest animals. Alpine highlands are dominated by alpine vegetation such as wildflowers, mosses, low grasses, and the magnificent snow gums (a kind of Eucalypt), and inhabited by alpine animals. In southern and south-eastern Australia are temperate forests and woodlands. Many of them are dominated by eucalypts. Eucalypts, the largest tree family in Australia, have adapted to all Australia’s climatic regions from arid deserts to cold snowfields and in the process developed into more than 900 separate species. Koalas can be found only in three species of Eucalypts. Eucalypts contain inflammable oils that make them highly fire-prone and the seeds of many species rely on fire to germinate. This in combination with hot summers is the reason why this part of Australia gets a lot of bushfires.
Australian Plants: Other Interesting Communities In forests of south-western Western Australia are the giant karri and jarrah trees. Western Australia is also known for its wildflowers – there are more than 10,000 species of them and 70% are endemic (which means found nowhere else in the world). The tropical Top End of Northern Territory is known for pandanus trees, while in the northern parts of Western Australia, there are tropical woodlands in the Kimberley region, known for the distinctive boab trees, also called bottle trees, which are found almost no-where else in Australia. And, on the coastal areas around Australia is a variety of different types of palm trees and mangrove communities.
Australian Desert Plants The rest of Australia is either arid or semi-arid. The native grasslands in semiarid environments are dominated by Mitchell grass, tussock and blue grasses. Trees are mainly eucalypts, acacias, paperbark trees (Melaleuca spp), and she-oaks (Casuarina spp). The arid environments - real Australian deserts - support Australian desert plants with some amazing adaptations, like mulga, mallees (multistemmed eucalypts), and hummock grasses, commonly known as Spinifex. Australian desert animals also have some interesting adaptations to survive in this harsh environment.
Courtesy of Tourism Queensland
Australian Plants: Wind Pollination and Insect Pollinator The harder the conditions, the more has evolution lead to changes. Nowhere else in the world have plants adapted to as large pollinators as in Australia. In a European pine forest for example, wind is good enough a pollinator because another pine tree is close by and easy for pollen to reach. In more species-rich environments, random pollinator like wind becomes useless because with many different plant species, chances are the pollen doesn’t end up on the right plant. There, insects are good pollinators because they tend to specialise on same plant species and so carry the pollen where it’s meant to go.
Australian Plants: Banksia Flower and Bottle Brush Flower Insects do eat nectar from plants even in Australia, but Australian plants don’t rely on insects as main pollinators. Australian plants grow large and strong flowers like banksias and bottle brush trees, to support – birds and even small mammals! For Australian trees that sometimes lie far away from each other, birds and small mammals are much better pollinators than insects – they carry more pollen and fly farther.
Courtesy of Tourism Queensland
Flower Pollination by Birds and Mammals Not one single tree in Europe has adapted to pollination by a bird, let alone mammals, while in Australia this has even given them their names: sugar glider, honey possum, blossom-bat. Honeyeaters is Australia’s largest bird family, and many species of possums, gliders, bats and marsupial mice feed on nectar from trees and are the main pollinators of trees.
Courtesy of Tourism Queensland
Flower Power - Bats and Noisy Miners This of course gives the trees some impressive flowers, but it can also be a risky business. Birds and bats get much more aggressive than insects about their feeding territory. Noisy miners for example, Australian native honeyeaters, are aggressive birds. They form groups about 200 and chaise all other birds away from their territory. But trees need treatment by more than one pollinator species. Noisy miners don’t eat enough of the sap-sucking psyllids, and so the trees can die.
NOTE: This website is written in British English, which is the English we use in Australia. You will find words like "traveller", "harbour" and "realise", and they are all correct in the language used in Australia.
