In the first continental analysis of the effects of climate change on a faunal group, we identified that the climate space of 101 Australian terrestrial and inland water bird taxa is likely to be entirely gone by 2085, 16 marine taxa have breeding sites that are predicted to be at least 10% less productive than today, and 55 terrestrial taxa are likely to be exposed to more frequent or intense fires.
Birds confined to Cape York Peninsula, the Wet Tropics, the Top End of the Northern Territory (particularly the Tiwi Islands), the arid zone, King Island and southern South Australia (particularly Kangaroo Island) are most likely to lose climate space. There was some variation in the predictions of the 18 climate models deployed, but all predicted that the rainforest avifauna of Cape York Peninsula is likely to face the strongest challenge from climate change, particularly taxa currently confined to the Iron and McIlwraith Ranges. For marine birds, those nesting on Lord Howe and Norfolk Islands, the Great Barrier Reef and the Houtman Abrolhos are likely to face the greatest declines in local marine productivity. Changes in local marine productivity may also affect the endemic terrestrial birds of these islands, for which no climate modelling was possible. A small group of beach-nesting and saltmarsh birds may be affected by sea level rise.
Many taxa, and particularly seabirds, are potentially highly sensitive to climate change based on a set of ecological and morphological metrics. Small island taxa were most likely to be both exposed and sensitive to climate change, followed by marine and shoreline taxa. While threatened birds were more likely than non-threatened taxa to be exposed or sensitive to climate change, or both, a substantial proportion was neither.
A key action that needs to be undertaken immediately is fine scale modelling of regions identified as having numerous highly exposed bird taxa, in order to identify climatic refugia within the landscape. Such refugia can then be secured and managed appropriately for the future. The most urgent ongoing action is monitoring, with support for the Atlas of Australian Birds seen as a particularly cost-effective investment. In the future, the most expensive actions will be management of refugia, and captive breeding should all other approaches to conservation in the wild fail. However, most of those for which captive breeding is recommended as a last resort are subspecies of species that are widespread, either in Australia or in New Guinea.
For in situ management, the most important actions will be those that are already important – fire management, weed and feral animal control and, for marine taxa, controls on fishing. A small number of species-specific actions are suggested, and there appears to be no urgent requirement for corridors for the maintenance of taxa likely to be threatened with extinction – those few taxa not already living in areas where there are likely to be refugia will require assistance to colonise new climate space.
The cost of management over the next 50 years for persistence in the face of climate change of the 396 bird taxa that are very highly exposed, sensitive or both is estimated at $18.8 million per year – $47,700 per year for each taxon. The biggest ongoing costs are monitoring and direct species management but refugia management and captive breeding may eventually be needed, and will be much more expensive.