Spring is almost here and WA's southwest is about to burst into a colourful spectacle of magnificent wildflowers. People come from all over the world to experience the stunning natural beauty of one of the world’s biodiversity hotspots.
Cockies Tongues - Wilyabrup Cliffs - Cape to Cape, Margaret River
But what are biodiversity hotspots?
These are areas around the world (17 to be exact) where native & locally endemic species[1] are found in great quantities and diversity within ecosystems that are threatened but mostly intact. Australia is one of these ‘megadiverse’ areas.
According to the Department of Environment and Energy 84% of plants, 83% of mammals and 45% of birds in Australia are found nowhere else on the planet. What is more, out of the 15 Australian regions recognised as containing floral and faunal biodiversity, 8 are in Western Australia!
Stretching from Shark Bay all the way to Israelite Bay - that's over 300,000 square kilometres – WA’s southwest is of particular importance because of its distinctive plant biodiversity.
Royal Hakea - Fitzgerald River National Park
Why here?
In brief, when the supercontinent Gondwana started to separate 180,000 million years ago into what is now South America, Antarctica, Australia, Africa, India and Arabia, Australia’s southwest broke up from India and evolved in isolation – tens of millions of years of isolation.
In addition to that, WA’s southwest (also known as the Kwongan) was further isolated so that its species were protected from major extinctions caused by climatic changes such as glaciers allowing for 'localised evolution'; this is why about 50% of species in the southwest are endemic.
Acacia Glaucoptera - Flat Acacia in the Ravensthorpe Ranges
For example, there are more than 1,000 species of Acacias (the largest plant genus in Australia) and almost 700 Eucalyptus and in the southwest both are remarkably diverse. One example of the way Acacias have evolved is the way their roots host a bacteria that allows them to capture nitrogen from the air and survive in nutrient poor soils. Likewise, Eucalyptus is a host to a range of fungi and insects such as the ‘scribbly gum moth’ whose larvae feeds on the cells just under the bark of trees.
One of many Eucalyptuses in the Fitzgerald Biosphere
Here are two of our favourite West Australian hotspots.
The Fitzgerald River Ravensthorpe Hotspot
This is a UNESCO listed biosphere reserve belonging to a network of 669 reserves across the world, and is globally recognised for its natural diversity and significance. As well as containing the Fitzgerald River National Park, it also includes the towns of Ravensthorpe, Hopetoun, Jerramungup and Bremer Bay. Needless to say, the biosphere is choc-a-bloc with more than 1,600 species of plants, with many rare and endangered species - enough to hit anyone's hotspot!
Qualup Bells - Pimelea physodes - East Mt Barren - Fitzgerald River National Park
Here are some of the plants we have spotted here:
The Busselton Augusta Hotspot
Purple Enamel Orchid - Cape to Cape Track
Home to the iconic coastal Cape to Cape track this region is home to hundreds of different plants, many endemic. It contains coastal heaths, woodlands, and forests including the spectacular Boranup Forest with large Karri & Marri Eucalyptus.
Here are some of the diverse plants we have spotted here:
Yellow Cockies tongues - Cape to Cape Track
[1] A scientific definition of biodiversity includes all forms of life, from microscopic bacteria to human beings, in addition to the ‘…genetic material within each species and the diversity of ecosystems that those species make up, as well as the ecological and evolutionary processes that keep them functioning and adapting.’ CSIRO, 2014