Southwest Australia facts for kids

Ecoregions of Southwest Australia, as defined by the WWF. 1. Jarrah-Karri forest and shrublands; 2. Southwest Australia woodlands and Swan Coastal Plain; 3. Southwest Australia savanna; 4. Coolgardie woodlands; 5. Esperance mallee.

Southwest Australia is a special natural area in Western Australia. It has a unique Mediterranean climate, which means it has wet winters and dry summers. This region is home to many different kinds of plants and animals that you won't find anywhere else in the world!

It's so special that it's also called the Southwest Australia Global Diversity Hotspot. This means it's one of the most important places on Earth for biodiversity.

Geography of Southwest Australia

This region covers a huge area, about 356,717 square kilometers. Imagine a broad flat area along the coast, stretching 20 to 120 kilometers wide. Inland, you'll find gently rolling hills made of old rocks like granite and gneiss, and a reddish soil called laterite.

The highest point in Southwest Australia is Bluff Knoll in the Stirling Range, which is 1,099 meters tall.

To the north and east, dry deserts separate Southwest Australia from other parts of the continent. This isolation helps make the plants and animals here so unique.

Climate in Southwest Australia

Southwest Australia has a Mediterranean climate, just like parts of California, Chile, South Africa, and the Mediterranean Sea area. This means winters are wet and cool, while summers are hot and dry.

In winter, winds from the west bring clouds and rain. In summer, the winds change, bringing dry, warm weather. Sometimes, strong storms called tropical cyclones from northern Western Australia can reach as far south as Perth, bringing heavy rain and strong winds.

Rainfall is highest in the Karri Forest Region, near Pemberton and Walpole, where it can get up to 1,400 mm (about 55 inches) of rain each year. Generally, it gets drier as you go north or further from the coast.

Climate Change Effects

The climate here is changing. Since the 1970s, the average yearly rainfall has dropped by as much as 20%. Summers are also getting hotter, with temperatures increasing. For example, in Perth, the number of days over 40º C has doubled in the last 100 years. These changes mean less water in rivers and dams, which affects drinking water and farming. The summer of 2021/22 was the hottest ever recorded in the region.

Flora: Unique Plants of Southwest Australia

Southwest Australia is famous for its amazing plant life. It's known as a floristic province, which means it has a very distinct collection of plants.

The plants here are mostly woody, like those found in forests, woodlands, and shrublands. You won't find many natural grasslands. Common types include Eucalyptus trees, eucalyptus mallee (smaller, multi-stemmed trees), and kwongan shrublands. These are similar to chaparral in California or fynbos in South Africa.

The soils in this region are often sandy and don't have many nutrients. This has led to many different plant species evolving to fit specific tiny habitats. Many plants here are endemic, meaning they grow nowhere else. The protea family (Proteaceae) is especially diverse here.

Carnivorous Plants

Southwest Australia is a hotspot for carnivorous plants! More than half of the world's species of sundews (Drosera) live here. You can also find unique bladderworts (Polypompholyx), two types of rainbow plants (Byblis lamellata and B. gigantea), and the special pitcher plant Cephalotus follicularis. This pitcher plant is the only species in its entire plant family!

Fauna: Amazing Animals of Southwest Australia

This region is home to many animals you won't find anywhere else.

The honey possum (Tarsipes rostratus) is a tiny marsupial that lives only in Southwest Australia. It eats nectar and pollen, and it's super important for helping certain plants, like Banksia attenuata and Banksia coccinea, make seeds. Other unique mammals include the western brush wallaby (Macropus irma) and the famous quokka (Setonix brachyurus).

Endemic Birds

Southwest Australia is an Endemic Bird Area, meaning many bird species live only here. Some of these special birds are the long-billed black cockatoo (Zanda baudinii), western corella (Cacatua pastinator), noisy scrubbird (Atrichornis clamosus), red-winged fairywren (Malurus elegans), western bristlebird (Dasyornis longirostris), and red-eared firetail (Stagonopleura oculata). Sadly, one bird, the western rufous bristlebird, is now extinct.

Ecoregions of Southwest Australia

Scientists divide Southwest Australia into different "ecoregions" based on their climate, plants, and animals. The World Wide Fund for Nature (WWF) and the Interim Biogeographic Regionalisation for Australia (IBRA) have identified six main ecoregions here:

• Coolgardie woodlands
• Esperance mallee
• Jarrah-Karri forest and shrublands
• Southwest Australia savanna
• Southwest Australia woodlands
• Swan Coastal Plain scrub and woodlands

Some of these regions, like Coolgardie, are drier than others. While the WWF includes them in Southwest Australia, some other groups consider them part of Central Australia.

Freshwater Life

Southwest Australia has several rivers and streams that flow all year round, like the Swan–Avon system and the Blackwood River. These rivers get most of their water during the wet winter months. They flow from the inland hills across the coastal plain.

Because dry regions separate Southwest Australia's freshwater habitats from other rivers in Australia, the aquatic life here is very special and unique. Many species of fish and other water creatures are found nowhere else.

Freshwater Fish and Their Adaptations

There are fifteen types of freshwater fish here. Nine of them live only in fresh water and are found only in Southwest Australia. For example, the salamanderfish (Lepidogalaxias salamandroides) is the only species in its entire family! This amazing fish can survive the dry summers by burying itself in the mud and going into a deep sleep, a process called aestivation.

Other unique fish include the nightfish (Bostockia porosa), western mud minnow (Galaxiella munda), and western pygmy perch (Nannoperca vittata). Even some fish that usually live partly in the sea, like the common galaxias (Galaxias maculatus), have adapted to live their whole lives in the fresh waters of Southwest Australia.

Turtles

Two types of turtles are also unique to Southwest Australia: the southwestern snake-necked turtle (Chelodina colliei) and the western swamp turtle (Pseudemydura umbrina).

History of Southwest Australia

People have lived in Southwest Australia for a very long time. The first signs of human life here date back about 50,000 years ago, at a place called Devil's Lair. These were the ancestors of today's Aboriginal people.

Aboriginal people, especially the Noongar peoples, lived across the region. They were very skilled at managing the land, often using fire to keep the forests open and encourage new plant growth. This helped create the open woodlands and savannas we see today. The Noongar people have a special calendar with six seasons, which helps them understand the changes in nature throughout the year.

European settlers arrived in 1826 near Albany. They started farms, growing crops like wheat and raising sheep and cattle. Their arrival also changed the way the land was managed, including the use of fire.

Protected Areas

To protect this unique region, a large part of Southwest Australia is set aside as protected areas. About 22% of the land, which is 109,445 square kilometers, is protected. This helps keep the special plants and animals safe for the future.