Change in effective area of similar ecological environments
- The effective area of similar ecological environments is a measure of the total area of land with an environment similar to that of a particular location. It is thus is an index of the amount of suitable habitat available, and thus the potential long-term persistence of biodiversity.
- Change in effective area of similar ecological environments can arise due to climate change, land use practices, or both.
- Change in effective area of similar ecological environments is calculated by first estimating the area of locations that are similar to a particular location at a baseline and under a scenario (climate, land use or both). Change is then expressed for that location as a proportion, dividing the effective area under the scenario by the effective area of the baseline (figure below). This is calculated for every location in Australia.
- If there is a decrease in effective area of similar ecological environments in the future, we expect a corresponding loss of original biodiversity due to loss of suitable habitat.
Click on the boxes below to explore examples at national and regional scales.
Example national context
The national pattern of change in effective area for mammals (as a result of climate change alone) by 2050 under the high emissions’ mild MIROC5 climate scenario is moderate. Greater losses are projected (i.e., reduced capacity to support all the original mammal species) in parts of northern Australia (darker shading), and lesser reduction in effective area (lighter shading) is projected along the southern edges of the continent and in Tasmania.
The comparable projection of change in effective area for mammals that includes the effects of past land clearing in addition to climate change effects under the high emissions’ mild MIROC5 scenario leads to a much more severe outlook for the intensively utilised agricultural zones of southern and eastern Australia, including parts of Tasmania.
Example regional focus
A regional view of change in effective area for reptiles in Tasmania under the high emissions’ mild MIROC5 scenario suggests considerable local variability in the degree of gain or loss of reptile environments, when considering climate change alone. Some ecological environments, particularly the broad river valleys in the southeast, are showing an increase in the area of suitable habitat (green shading), which is an uncommon projection for most parts of Australia and suggests high buffering potential.
However, accounting for the effects of past land clearing in addition to the effects of climate change shows that much of this buffering potential in the state has already been lost.
Ideas for using change in effective area of similar ecological environments in planning are available under Planning Examples.