A Biodiverse Land

Article | Updated 5 months ago

The landscapes surrounding Kalgoorlie have been described as ‘a rich tapestry connecting Australia’s south-west corner to its inland deserts.’

They comprise of extensive undulating plains of eucalypt and acacia woodlands and heaths, vast expanses of stony and sandy deserts dominated by shrubs and spinifex (Triodia spp) grasslands, the relatively featureless and treeless Nullarbor Plain and vast granite domes, breakaways, ironstone ridges and salt lakes.

Above all, the landscapes comprise abundant biodiversity that is a reflection of the different landforms, soils and vegetation types the area encompasses.

The region has the highest diversity of the genus Eucalyptus anywhere in the world, with many species being found only in this region. There is also a great richness of vertebrate and invertebrate fauna. Eleven threatened vertebrate species occur, comprising the two species of Mulgara, two species of Marsupial Mole, Sandhill Dunnart, Bilby, Black-footed Rock-wallaby, Malleefowl, Australian Painted Snipe, Night Parrot and the Giant Desert Skink.

Great Western Woodlands

The largest and healthiest temperate woodlands on Earth are centered south and west of Kalgoorlie.

They make up the Great Western Woodlands of the semi arid interior of Western Australia. These globally significant woodlands cover over 9 million hectares, and are complemented by a further 2.3 million hectares of mallee formations, also dominated by eucalypts, to provide an extensive area of treed landscapes across large tracts of country.

These magnificent woodlands and mallees are rich in biodiversity with high levels of endemism (unique to a particular locality) among their plants and fauna. They contain over 3300 plant species, including more than one third of all known eucalypt species, and around 50 mammal, 150 reptile, 20 frog and 230 bird species.

Acacia (Mulga) Shrublands

Vast areas of acacia-dominated shrublands lie to the north of Kalgoorlie extending toward the fringes of the deserts in the east and northeast. They have evolved and flourished in the low rainfall and nutrient poor soils of the arid interior.

These acacia shrublands, dominated by Mulga, Acacia aneura, define the broad limits of the pastoral industry and are transitional between the biodiverse eucalypt dominated woodlands and mallees of the south and west and the extensive Triodia deserts of the interior.

Extensive grazing by sheep, goats and cattle has degraded both the soil and vegetation structure. Together with the creation of artificial watering points over the last 100 years, a modified landscape has appeared.

Heaths

The extensive heaths that occur west and southwest of Kalgoorlie contain a rich and varied array of plant and animal species. Many of these species occur at the limits of their distributions in this area where winter rainfall is prominent and soils are generally sandy and occur in undulating plains.

The diverse species that occur and flower at different times throughout the year are very important. They are a food resource for birds, such as honeyeaters, and insects, such as the spectacularly colourful jewel beetles, which flowers rely on for pollination in return.

Heaths are also very susceptible to fire. The major ‘fire scars’ that can be seen in satellite images or aerial photos of the region occur in these extensive heath lands.

Spinifex Grasslands

Deserts define central Australia and form a major part of the Goldfields region. They are extensive and generally waterless with little variation in plant diversity. However, they are home to a diverse array of animal species, particularly reptiles and termites.

Dominated by the hummock grasses that comprise the genus Triodia, these grasslands usually occur on the red sand plains and dunes that define the major deserts of the inland.

When Triodia grassland has either Marble Gum or Desert Oak emergent trees they become open savanna woodlands that can cover extensive areas.

Spectacular seeding of hummock grasses after episodic rainfall provides essential nourishment to vast numbers of ants and large flocks of granivorous (grain and seed feeding) birds, such as finches and budgerigars.