Adaptation strategies for Australian birds

Adaptation Research Grants Program
Stephen Garnett
Charles Darwin University
Year Started: 
Northern Territory

Executive summary from final report:

All Australian bird taxa were assessed for their vulnerability to climate change employing the risk model that vulnerability arises from a combination of sensitivity and exposure. We concentrate on identifying those taxa for whom climate change poses a risk of extinction.

Sensitivity to climate change was assessed using seven metrics representing specialisation (food types, feeding habitats, foraging substrates, climate specialisation and relative brain size), reproductive capacity (maximum annual rate of reproduction) and genetic variability (population size). Collectively, these directly or indirectly represent intrinsic traits that are related to the capacity to adapt to climate change. Marine birds were most likely to be sensitive to climate change, followed by those from small islands. Those from mangroves and inland waters had the lowest scores against the sensitivity metrics used.

Over 16.5 million bird location records of 1232 ultrataxa were analysed to assess the probable exposure of Australian bird taxa to climate change. For taxa of terrestrial environments and inland waters, 18 climate models were used to identify the median area of climate space suitable for each taxon in 2085 based on the assumption that current rates of greenhouse gas emissions will continue unabated. For marine taxa, the proxy for exposure used was the projected change in primary productivity in seas within 200 NM of their breeding colonies (i.e. the limits of the Australian Fishing Zone). In the absence of climate models, it was assumed that islands in waters where marine productivity declines may also suffer from an altered climate. The exposure of coastal and mangrove taxa was assessed subjectively based on projections for sea level rise.

Among terrestrial and inland waters bird taxa, exposure is likely to be greatest for taxa confined to Cape York Peninsula, the Wet Tropics, the Top End of the Northern Territory (particularly the Tiwi Islands), the central and southern arid zone, southern South Australia (particularly Kangaroo Island) and King Island. In addition, 61 terrestrial taxa were assessed as being exposed to the effects of projected increases in the intensity and frequency of fires. For marine taxa, projected productivity declines are greatest off eastern Australia, including around Norfolk and Lord Howe Islands, and around the Houtman Abrolhos in south-western Australia. A small number of beach-nesting and saltmarsh taxa are likely to be exposed to sea-level rise. While threatened birds were more likely to be exposed, sensitive or both, many were not and many non-threatened taxa had high scores for exposure and sensitivity metrics.

Modelling of refugia and a continuation of species management are the principal actions recommended for immediate implementation. In the future, refugia management and captive breeding are likely to dominate budgets for climate change adaptation. By far the most important actions are to continue to manage the current stressors to birds including fire, feral herbivores and predators, weeds and fishing, as these are likely to interact synergistically with climate change. Land clearance or fragmentation did not feature among the threats to Australian birds under climate change in the near future. Similarly corridors, land purchase or habitat restoration had low priority for the most exposed or sensitive taxa.

The total cost over a 50-year period, without imposing a future discount rate or calculating net present value, is estimated to be $945 million – $2.4 million for each of the 396 bird taxa that are very highly exposed (177), sensitive (151) or both (68). This amounts to $19.8 million per year – $47,700 per taxon.

View the final report