An assessment of 13 Australian ecosystems, including the wet tropics of far north Queensland and rare Western Australian shrubland, has found that climate change dramatically increases the impact from urban development, agriculture and invasive species.
This is the first research of its kind to assess Australian ecosystems based on the International Union for Conservation of Nature’s Red List criteria which has traditionally focused on the status of individual species rather than landscapes. The Red List includes more than 77,000 assessed species, of which nearly 23,000 are threatened with extinction, and under the List, 8 of the 13 ecosystems would be either endangered or critically endangered.
Study lead Professor David Keith of the University of New South Wales said that the study showed tat climate change is already leaving its imprint on significant portions of the environment, mainly due to cutting across everything, in contrast to habitat loss and diseases which tend to be specific to individual systems.
A decline in rainfall in the South West of Western Australia poses a threat to diverse but rare shrublands that rely on moisture during a critical growth window for seedlings. In contrast, forests on mountains on Lord Howe Island are drying out because rain bearing clouds are becoming less frequent. Professor Keith pointed out that as ecosystems lose species, as a result of changes in land use or invasive species, that loss reduces their resilience. In particular, as native herbivores are taken out, the soil isn’t being turned over, which also impacts species that may not be directly impacted on initially.
One example was the Cumberland Plain woodland system near Sydney, which had been cleared for grazing and cropping and only 10% of the original area is still intact. The native mammals are extinct and the bird species are in decline, according to Keith. The rate of decline in Australia is amongst the world’s worst, and Keith is adamant that this needs to be reversed. In total 50 species have become extinct in the past 200 years, which is one of the largest extinction rates in the world. Nearly 90% of Australia’s plants and animal species aren’t found anywhere else on Earth.
The WWF has estimated that 3-6 million hectares of rainforest and temperate forest (the majority of which is in New South Wales and Queensland) could be lost between 2010 and 2030 based on current trends.