Interactions between climate change, fire regimes and biodiversity in australia - a preliminary assessment
Williams, RJ and Bradstock, RA and Cary, GJ and Enright, NJ and Gill, AM and Liedloff, AC and Lucas, C and Whelan, RJ and Andersen, AN and Bowman, DMJS and Clarke, PJ and Cook, GD and Hennessy, KJ and York, A, Interactions between climate change, fire regimes and biodiversity in australia - a preliminary assessment , CSIRO, Canberra, pp. 196 (2009) [Minor Creative Work]
Climate change will affect fire regimes in Australia through the effects of changes to temperature, rainfall, humidity, wind – the fire weather components - and through the effects of increases in atmospheric CO2, and changes in moisture, on vegetation, and therefore fuels.
Examination of weather data from south-eastern Australia over the period 1973-2007 shows that fire danger (as measured by the annual sum of the commonly-used Forest Fire Danger Index) rose by 10-40% at many sites from 2001-2007 relative to 1980-2000. Increases in fire danger have also been detected in some other parts of Australia.
Climate change projections are for warming and drying over much of Australia, and hence an increased risk of severe fire weather, especially in south-eastern Australia. Modeling suggests an increase of 5 to 65 per cent in the incidence of extreme fire danger days by 2020 in this region.
Climate change will have complex effects on fuels. On one hand, elevated CO2 may enhance vegetation production and thereby increase fuel loads. On the other hand, drought may decrease long-term vegetation production (thereby decreasing fuel loads) and may decrease fuel moisture (thereby increasing potential rates of spread). The outcome of these processes on fuels, and hence fire regimes, are highly uncertain, and require further research.
Fire regimes within Australia differ because of variation in key drivers such as fuel accumulation and drying, fire weather and ignitions. Climate change may be expected to affect fire regimes more in regions where the constraining factor(s) are fire weather-related (e.g. temperate forests of the south-east), than in places where the fire regimes are determined more by fuel or ignition rather than fire weather (e.g. tropical savannas of the north)
Future fire regimes will also be affected by other agents of change, such as invasions of exotic species that may affect fuel loads. Simulation modeling of climate change impacts on fire regimes in the Australian Capital Territory (ACT) predicted that a 2ºC increase in mean annual temperature would increase the landscape measure of fire intensity by 25%, increase the area burnt, and reduce intervals between fires.
Climate change and changed fire regimes will have complex feedback (positive and negative) interactions with biodiversity, with different potential outcomes for different Australian biomes. There may be increased risks to both interval and intensity-sensitive species, as a consequence of changed climate and changed fire regimes. Climate change will probably have the most significant impacts on both the fire regimes and biodiversity of sclerophyll dominated vegetation such as the forests of south-eastern Australia and south-west
Managing fire regimes to reduce risk to property, people and biodiversity under climate change will be increasingly challenging. In Australia, management of fire regimes for biodiversity conservation has variously emphasized fire detection and suppression, and fuel management. There needs to be an enhanced research effort on the complex interactions between fire, biodiversity, people, fuel management and land use change, to help meet these challenges.