Climate change is one of the greatest threats the Great Eastern Ranges faces and poses a major threat to biodiversity worldwide. It is listed as a key threatening process under the Environment Protection and Biodiversity Conservation Act 1999 and will adversely affect species in a number of ways including:
- changing the habitat in which animals and plants live;
- promoting algal blooms growing in warmer water and competing with native fish for oxygen;
- increasing temperatures – reducing snowfall in sensitive alpine regions;
- changing rainfall patterns;
- increasing extreme weather events such as cyclones, thunderstorms and heatwaves; and
- altering ecological patterns such as fire and water regimes.
In addition to its direct effects, climate change will also exacerbate a range of other major threats in natural areas. For example, the increased numbers of extreme weather events and disturbances such as fires bought about by climate change will increase habitat loss, fragmentation and degradation by further fragmenting remnant habitats and slowing regeneration. In turn, it may be particularly hard for native species to find the resources to adapt to climate change or migrate within highly modified and fragmented agricultural or urbanised landscapes.
Climate change may also worsen the problem of invasive species by increasing natural disasters, such as fires and floods, creating disturbed conditions in which weeds and pest animals thrive. Increased temperatures are also likely to favour weedy species over native plants in many cases, and allow pests such as the cane toad to expand their range across more of Australia.
Climate change in the GER corridor
The mountainous landscapes of the Great Eastern Ranges provide many different habitats over a range of elevations and latitudes, and connect natural habitats over long distances. These corridors of land provide a major opportunity for plants and animals to find refuges, migrate, disperse and adapt as the climate changes. Connectivity conservation is one of the primary ways of making ecosystems more resilient to the impacts of climate change and giving species a better chance of surviving the threats and changes that it will bring.
The GER corridor however, does include some of the most ecosystems most vulnerable to the impacts of climate change, such as alpine areas, rainforests and fragmented terrestrial ecosystems which already face a number of existing threats.
The corridor is also home to many iconic species, some of which are more at risk than others from climate change. These tend to be species that occur in isolated populations, are specialised, have long life spans or have narrow ranges. For example:
- Koalas are likely to be significantly affected by climate change, as they are sensitive to heat, and chemicals in the leaves they feed on will change in response to rising carbon dioxide levels.
- The sooty owl (Tyto tenebricosa) depends on the rainforests and moist eucalypt forests of the Great Eastern Ranges. Climate change will make these habitats drier and more vulnerable to fire.
- The endangered mountain pygmy-possum (Burramys parvus) occupies a specific habitat in the Australian Alps. The greatest threat faced by this species is a reduction in snowfall brought about by increasing temperatures. As the possums rely on snow cover to insulate them as they hibernate in winter, reduced snowfall will increase their risk of freezing, starving or being found by predators.
- It is estimated that 25% of Australia’s eucalypt species occur in areas where a small change in temperature could have a dramatic effect on their distribution.
- Marsupials in the Great Eastern Ranges are descended from ancient animal groups that appeared 20 million years ago. The rainforests of northern New South Wales are descendants of species that covered the Gondwana supercontinent 100 million years ago. Climate change could cause the extinction of species and end this link to the ancient past.
The impacts of climate change will therefore have to be carefully managed to ensure that the species of the GER corridor and the ecosystems that support them are given the best chance of survival.