Limestone layers along the Great Ocean Road have eroded at different rates to create tunnels and caves as well as spectacular natural structures like the Twelve Apostles and the Loch Ard Gorge. Erosion occurs at a rapid rate as the awesome power of the sea pounds the earth, collapsing one of the Twelve Apostles in 2005 and tumbling the London Bridge rock formation into the sea in 1990. The breathtaking cliff faces of the Great Ocean Road fall away to a spectacular marine environment with the intertidal zone supporting a vast array of crabs, molluscs, fish, seaweed and algae as well as fantastic bird life, including albatross, gannets, shearwaters, honeyeaters, Rufous Bristlebirds, cockatoos, eagles, harriers and colonies of Little Penguins.
A large low elevation volcanic lava plain (known as the Werribee Plain) runs west of Melbourne to South Australia, broken by an occasional extinct volcano, sedimentary escarpment or granite outcrop. Volcanoes began erupting lava flows about 4.5 million years ago, with the youngest eruptions as recent as 10 000 years ago. Due to the rain shadow created by the Otway Ranges, the You Yangs are located in a pocket of dry grasslands and woodlands. Eucalypts such as Manna Gum, Yellow Gum and River Red Gum give way to sparse undergrowth of native shrubs and groundcovers with patches of Wattle and Drooping She oaks. This region provides habitat for populations of Eastern Grey Kangaroo, Koala and Jacky Lizards.
The hinterland region of the Otway National Park has prolific plant growth, being amongst the wettest parts of Victoria. The region boasts dense rainforests of Myrtle Beech, Blackwood and Tree-ferns, with an understorey of low ferns, mosses and fungi. This provides habitat for Swamp Wallabies, Koalas and Short-beaked Echidnas. This National Park has been declared an Important Bird Area (IBA) because it supports populations of Rufous Bristlebirds, Striated Fieldwrens and Pink Robins. It is also home to the Otway Black Snail, an endangered carnivorous snail found in the parks wettest areas.
A spectacular variety of plants can be found in the region’s wind-pruned heathlands, with more than 700 species recorded. In Spring, the landscapes are transformed with an vibrant wildflower display, with 79 species of orchid found here; being one of the most orchid-rich sites in Australia. The coastal heathlands protect Southern Brown Bandicoots, Short-beaked Echidnas, Swamp Wallabies, Lowlands Copperhead Snake as well as 80 species of birds including the Crimson Rosella, Common Bronzewing and Singing Honeyeaters.