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F I R E AND B I R DS Fire Management for Biodiversity Compiled by Penny Olsen and Michael Weston Supplement to Wingspan, vol. 15, no. 3, September 2005 2 Fire and Birds Fire and Birds 3 ‘Fire is a force in terrestrial ecosystems that is equalled only by the impact of humans as they transform, fragment and degrade the Earth’s vegetation… Regardless of the changes wrought, fire is a central process in creating and maintaining ecosystem patterns and processes in most, if not all, Australian terrestrial ecosystems.’ John Woinarski & Harry Recher 1997 Fire is part of Australians’ heritage—it has and continues to shape much of our natural world. Historically, a fine-scale mosaic of different aged burns predominated, but since the early 20th century there has been an increase in hotter, extensive fires, more threatening from both a human and biodiversity perspective. Such inappropriate fire regimes, including the exclusion of fire, threaten over 50 bird species and subspecies and, since European settlement, have contributed to the extinction of two species. Yet inappropriate management of fire is one of the most tractable of the major threats to Australia’s wildlife. To some extent the old adage ‘fight fire with fire’ applies. Used well, fire is an effective, economical tool for land managers. Reintroduction of occasional fire into some landscapes, and return to a finer mosaic of burning, will not prevent wildfires; it may, however, reduce their impact, by maintaining fire-dependent habitat and protecting fire-sensitive birds. There will always be uncertainty, but by striving for practical and effective fire management objectives we can better manage the risks to both human life and property, and biodiversity. Fire regime—the pattern of fire in a particular area over a number of years, including seasonality, frequency, interval between fires, intensity, extent and patchiness Above: Black Kites at a grassfire in the Kimberley, Western Australia, catching animals flushed by the smoke and flames. Photo by Dennis Sarson, Lochman Transparencies Left: The habitat of the Southern Emu-wren is vulnerable to wildfires in the dry seasons, but also threatened by deliberate burning for pasture. Photo by Nicholas Birks KEY POINTS • Fire is an essential, natural force in the Australian landscape. Every year the continent has a large number of wildfires, caused by lightning or humans. Most are not regarded as disasters. • Biodiversity loss is associated with high fire frequency, intense broadscale fire, and fire exclusion, all of which tend to homogenise the landscape. Increasing loss of habitat heterogeneity from the landscape is the single most damaging effect of poor fire management. • Some 50 bird taxa and their habitats are currently threatened by inadequate, ill-informed fire management. • The response of birds to fire is influenced by their life history characteristics and habitat needs. Hence, individual species may vary in their response to fire, and particular fire regimes (including fire exclusion) are essential to the survival of some species. • The remaining populations of birds most threatened by inappropriate fire management occur in coastal heath and thickets, mallee and northern grasslands and woodlands—often areas of low human population. • Land managers are seeking to incorporate ecological requirements into their management decisions and actions, and most States and Territories now require land managers to manage fire in fire-prone vegetation, and to use fire in ecologically sustainable ways. • Fire management can generally be incorporated into management plans in such a way that neither biodiversity conservation nor other goals, particularly protection of human life and property, are sacrificed. • It is important to identify regimes known or suspected to cause biodiversity and threatened species loss and manage the land to avoid these regimes. • Maintaining a mosaic of habitats of different fire ages is recommended for large area fire management, but where habitats are small, fragmented and isolated, the options are fewer and the issues more complex. • Across the north, regulation of exotic pasture grasses is a high priority for fire management and biodiversity conservation. • Fire management must be ongoing and adequately resourced. • There is a need for greater awareness, research and understanding of the role of fire in natural systems. • In the absence of complete knowledge to guide management, it is prudent to apply the precautionary principle (that is, pursue the fire regime that is likely to be lowest risk in terms of environmental damage) and adaptive management. • There is a need for a set of simple, flexible guidelines to help land managers manage fire for biodiversity conservation. OVERVIEW Birds to Watch For several bird species an inappropriate fire regime is the only major threat to their survival. Without continued implementation of effective fire regimes, these species are likely to move closer to extinction in the near future. They include: the Ground Parrot, Noisy Scrub-bird, Eastern Bristlebird, Western Bristlebird and Western Whipbird. The Partridge Pigeon, Malleefowl, Golden-shouldered Parrot, Black-eared Miner and, possibly, the Night Parrot are also at great risk from inappropriate fire regimes, among other threats. Inappropriate fire regimes are the greatest threat to Australia’s birds after direct human destruction and alteration of habitats. Potentially, they are also one of the most manageable of threats. The introductory pages of this supplement summarise the key points from a diffuse and often contradictory literature on the interaction between fire and birds. They are complemented by stand-alone narratives authored by ecologists concerned that we are often failing in our management of fire. While there is certainty that current fire regimes are often damaging to the land and its wildlife, there is still much to learn about effective fire management to conserve biodiversity. Our hope is that this report will lead to greater awareness of the issues, implementation of bird and biodiversity-friendly fire management regimes, and refinement in knowledge of appropriate burning practices. Australia has long been a dry, fire-prone country and for some 60,000 years people have used fire to manipulate the continent’s vegetation and wildlife. So commonplace is fire that much of the Australian biota has adjusted to occasional burning. ‘You got to burn the country… not leave him until he really dry, that means you destroy everything… cook it… Soon as wet season stop… grass starting to dry out, you burn grass then… so you don’t burn all the animals… if you burn it [then], some have a place to hide, but if you leave him, and you burn the grass you kill everything, that’s no good.’ Musso Harvey of the Yanyuwa people of the Gulf of Carpentaria (quoted in Baker 2003) ‘Fire, grass, kangaroos and human inhabitants seem all dependent on each other for existence in Australia, for any one of these being wanting, the others could no longer continue.’ Sir Thomas Mitchell, Journal of an Expedition into the Interior of Australia (1848) In many habitats, fire histories and Indigenous explanations reveal a pre-European landscape of small burnt patches of various stages of fire succession, maintained by a system of burning which controlled the build-up of fuel, and reduced the incidence of large, intense fires. Since European occupation the magnitude and rate of change in human-fire interactions has increased markedly. In the early days after settlement, fire exclusion and suppression was a common practice in more highly developed areas, but deliberate burning was used in many outlying areas to reduce fire hazards or maintain grazing values. Contemporary fire regimes have tended to be either of two extremes: intense, extensive and uncontrolled wildfire mainly late in the driest season; or land seldom burnt. This results in loss of firesensitive species, habitats and patchiness in intensively burnt areas, or wood thickening and loss of savanna, granivorous species and general biodiversity in areas seldom burnt. Near centres of human population, at the urban and agricultural interface, Australian authorities have adopted broad area burning to reduce fuel loads, and protect human interests; however, fire may escape, and arson is also common. Over time these policies, mistakes and misdemeanours lead to a loss of heterogeneity and biodiversity across the landscape. Until quite recently, European fire management has been directed at protection of human life and property. Now, biodiversity management is seen as important and there has been a shift towards its inclusion in legislation, 2 Fire and Birds Fire and Birds 3 ‘Fire is a force in terrestrial ecosystems that is equalled only by the impact of humans as they transform, fragment and degrade the Earth’s vegetation… Regardless of the changes wrought, fire is a central process in creating and maintaining ecosystem patterns and processes in most, if not all, Australian terrestrial ecosystems.’ John Woinarski & Harry Recher 1997 Fire is part of Australians’ heritage—it has and continues to shape much of our natural world. Historically, a fine-scale mosaic of different aged burns predominated, but since the early 20th century there has been an increase in hotter, extensive fires, more threatening from both a human and biodiversity perspective. Such inappropriate fire regimes, including the exclusion of fire, threaten over 50 bird species and subspecies and, since European settlement, have contributed to the extinction of two species. Yet inappropriate management of fire is one of the most tractable of the major threats to Australia’s wildlife. To some extent the old adage ‘fight fire with fire’ applies. Used well, fire is an effective, economical tool for land managers. Reintroduction of occasional fire into some landscapes, and return to a finer mosaic of burning, will not prevent wildfires; it may, however, reduce their impact, by maintaining fire-dependent habitat and protecting fire-sensitive birds. There will always be uncertainty, but by striving for practical and effective fire management objectives we can better manage the risks to both human life and property, and biodiversity. Fire regime—the pattern of fire in a particular area over a number of years, including seasonality, frequency, interval between fires, intensity, extent and patchiness Above: Black Kites at a grassfire in the Kimberley, Western Australia, catching animals flushed by the smoke and flames. Photo by Dennis Sarson, Lochman Transparencies Left: The habitat of the Southern Emu-wren is vulnerable to wildfires in the dry seasons, but also threatened by deliberate burning for pasture. Photo by Nicholas Birks KEY POINTS • Fire is an essential, natural force in the Australian landscape. Every year the continent has a large number of wildfires, caused by lightning or humans. Most are not regarded as disasters. • Biodiversity loss is associated with high fire frequency, intense broadscale fire, and fire exclusion, all of which tend to homogenise the landscape. Increasing loss of habitat heterogeneity from the landscape is the single most damaging effect of poor fire management. • Some 50 bird taxa and their habitats are currently threatened by inadequate, ill-informed fire management. • The response of birds to fire is influenced by their life history characteristics and habitat needs. Hence, individual species may vary in their response to fire, and particular fire regimes (including fire exclusion) are essential to the survival of some species. • The remaining populations of birds most threatened by inappropriate fire management occur in coastal heath and thickets, mallee and northern grasslands and woodlands—often areas of low human population. • Land managers are seeking to incorporate ecological requirements into their management decisions and actions, and most States and Territories now require land managers to manage fire in fire-prone vegetation, and to use fire in ecologically sustainable ways. • Fire management can generally be incorporated into management plans in such a way that neither biodiversity conservation nor other goals, particularly protection of human life and property, are sacrificed. • It is important to identify regimes known or suspected to cause biodiversity and threatened species loss and manage the land to avoid these regimes. • Maintaining a mosaic of habitats of different fire ages is recommended for large area fire management, but where habitats are small, fragmented and isolated, the options are fewer and the issues more complex. • Across the north, regulation of exotic pasture grasses is a high priority for fire management and biodiversity conservation. • Fire management must be ongoing and adequately resourced. • There is a need for greater awareness, research and understanding of the role of fire in natural systems. • In the absence of complete knowledge to guide management, it is prudent to apply the precautionary principle (that is, pursue the fire regime that is likely to be lowest risk in terms of environmental damage) and adaptive management. • There is a need for a set of simple, flexible guidelines to help land managers manage fire for biodiversity conservation. OVERVIEW Birds to Watch For several bird species an inappropriate fire regime is the only major threat to their survival. Without continued implementation of effective fire regimes, these species are likely to move closer to extinction in the near future. They include: the Ground Parrot, Noisy Scrub-bird, Eastern Bristlebird, Western Bristlebird and Western Whipbird. The Partridge Pigeon, Malleefowl, Golden-shouldered Parrot, Black-eared Miner and, possibly, the Night Parrot are also at great risk from inappropriate fire regimes, among other threats. Inappropriate fire regimes are the greatest threat to Australia’s birds after direct human destruction and alteration of habitats. Potentially, they are also one of the most manageable of threats. The introductory pages of this supplement summarise the key points from a diffuse and often contradictory literature on the interaction between fire and birds. They are complemented by stand-alone narratives authored by ecologists concerned that we are often failing in our management of fire. While there is certainty that current fire regimes are often damaging to the land and its wildlife, there is still much to learn about effective fire management to conserve biodiversity. Our hope is that this report will lead to greater awareness of the issues, implementation of bird and biodiversity-friendly fire management regimes, and refinement in knowledge of appropriate burning practices. Australia has long been a dry, fire-prone country and for some 60,000 years people have used fire to manipulate the continent’s vegetation and wildlife. So commonplace is fire that much of the Australian biota has adjusted to occasional burning. ‘You got to burn the country… not leave him until he really dry, that means you destroy everything… cook it… Soon as wet season stop… grass starting to dry out, you burn grass then… so you don’t burn all the animals… if you burn it [then], some have a place to hide, but if you leave him, and you burn the grass you kill everything, that’s no good.’ Musso Harvey of the Yanyuwa people of the Gulf of Carpentaria (quoted in Baker 2003) ‘Fire, grass, kangaroos and human inhabitants seem all dependent on each other for existence in Australia, for any one of these being wanting, the others could no longer continue.’ Sir Thomas Mitchell, Journal of an Expedition into the Interior of Australia (1848) In many habitats, fire histories and Indigenous explanations reveal a pre-European landscape of small burnt patches of various stages of fire succession, maintained by a system of burning which controlled the build-up of fuel, and reduced the incidence of large, intense fires. Since European occupation the magnitude and rate of change in human-fire interactions has increased markedly. In the early days after settlement, fire exclusion and suppression was a common practice in more highly developed areas, but deliberate burning was used in many outlying areas to reduce fire hazards or maintain grazing values. Contemporary fire regimes have tended to be either of two extremes: intense, extensive and uncontrolled wildfire mainly late in the driest season; or land seldom burnt. This results in loss of firesensitive species, habitats and patchiness in intensively burnt areas, or wood thickening and loss of savanna, granivorous species and general biodiversity in areas seldom burnt. Near centres of human population, at the urban and agricultural interface, Australian authorities have adopted broad area burning to reduce fuel loads, and protect human interests; however, fire may escape, and arson is also common. Over time these policies, mistakes and misdemeanours lead to a loss of heterogeneity and biodiversity across the landscape. Until quite recently, European fire management has been directed at protection of human life and property. Now, biodiversity management is seen as important and there has been a shift towards its inclusion in legislation, 4 Fire and Birds Fire and Birds Responses of birds to a single fire event The effects of a fire on bird communities can be difficult to predict. They vary with fire intensity, season and extent; the characteristics of the site, climatic variation before and after; and time elapsed since fire. Species differ in their response to fire and individual species vary in their response. In general, the Australian bush and its wildlife can cope with single fire events, but over time frequent, widespread fires change the character of the landscape and its inhabitants, to the detriment of fire-sensitive species. Before, during and after Flame Robin. Photo by Peter Merritt Large logs can act as micro fire-breaks, adding desirable heterogeneity to the habitat, and they offer refugia for animals in their moist interior. Regrowth in the early succession stages after fires, particularly in the south of the country (here Tiajara, NSW), attracts small insect-eaters such as Scarlet and Flame Robins. Photo by Graeme Chapman Some definitions Backburning: a fire that is intentionally lit to consume fuel in the path of a wildfire. Bushfire or wildfire: a general term used to describe a fire in native vegetation. Prescribed, controlled, fuel reduction, or planned burning: a fire lit under specified (i.e. relatively safe) environmental and weather conditions to burn over a predetermined area, at a time, intensity and rate of spread necessary to achieve particular management objectives. Fire-break: any natural or constructed discontinuity in fuel used to break up, stop or control the spread of a fire. Fire age: the time elapsed since the last fire. Fire intensity: the amount of energy released per unit length of the fire front, usually expressed as kilowatts (kW) per metre. Fire regime: the history of fire in a particular area, comprising the frequency, intensity, season of burning (i.e. the time of year a fire occurs) and the type. Type: refers to whether the fire is above-ground or below-ground (i.e. a peat fire), but as almost all fires in Australia are aboveground this component is usually irrelevant. Fire succession: the series of stages that vegetation goes through in its recovery post-fire. Fuel load: the amount of combustible material, especially easily ignitable material. Hazard reduction burn: a fire intentionally lit to reduce the amount of fuel, and consequently reduce the risk posed by wildfires. Fuel is any material, such as bark, leaf litter and living vegetation, which will burn. Trittering: mowing and mulching which involves pulverising the leaf litter so that it becomes compacted and burns more slowly with a reduced flame height. Adapted from the NSW National Parks & Wildlife Service Fire Management Manual (2001) policy and management (see ‘Bushfire management in the Northern Territory’ p. 16, ‘Tarawi Nature Reserve’ p. 5). Recent legislation in most Australian States and Territories not only requires that fire is managed by land managers in fire-prone vegetation, but that it is used in ecologically sustainable ways. The importance of periodic prescribed fire (controlled burns) to increase or maintain biodiversity is now widely accepted. Insights from Indigenous experience can help inform the development of effective fire management practices. Sadly, much of this knowledge has been lost or eroded. More importantly, landscapes are now substantially modified from those managed by Indigenous Australians—by weed invasion, introduced grasses, grazing, clearing and drainage; and reduced, fragmented habitats. These factors can dramatically alter fire impacts on landscapes and ecosystems. ‘I am confident that the indiscriminate burning of bush, which is the concomitant of all farming and grazing operations, is by a long way the major cause of the disappearance of many of our rarer birds.’ Edwin Ashby (1924) The environmental impacts of fire on natural ecosystems are not well understood due to the complexity of the problem, paucity of research, and megadiversity of the Australian landscape. There are few detailed long-term studies of the effects of fire on avian communities, but there is sufficient information on fire effects from a broad cross-section of Australian habitats to identify patterns of response to individual fires (see ‘Responses of birds to fire’ p. 5) and predict likely long-term effects. Depending on the severity of the fire, the amount of vegetation burned and killed, and the weather during the recovery period, most avian communities recover rapidly following single fires regardless of fire intensity. However, even single fires may pose a significant threat to species with restricted distribution, limited reproductive potential, poor dispersal ability and/or narrow habitat requirements. Birds persisting in fragmented habitats are particularly at risk because the whole fragment can burn and, post-fire, small fragments may not be recolonised by all of their original species. Nonetheless, far more threatening across a broad range of avian communities, are increases in fire frequency and extent, on the one hand, and fire exclusion on the other. These tend to homogenise the landscape, and offer fewer options for survival and recolonisation. Detrimental fire regimes have contributed to the extinction of two of the three bird species, and three of the four subspecies, lost since European colonisation. Inappropriate fire management is now a factor in the threatened status of over 50 nationally recognised threatened bird species (see table p. 6). Of those threatened species whose relationships with fire have been welldocumented, almost all show a preference for less frequent, less extensive fires than have occurred in recent decades. Though the task is daunting, the costs of inaction are great. Fire can be an economical way to manage large tracts of land, on a fine scale, with benefits to biodiversity and human needs. The challenge will be to identify and develop the appropriate fire regimes to maintain fire-dependent habitats and protect the fewer fire-sensitive habitats. The single greatest need for land managers incorporating fire into their management is a useful tool to determine appropriate fire regimes (see ‘To burn or not to burn’ and ‘Towards a set of biodiversity-friendly fire management principles’ p. 6). ‘There was a sound as of thunder, mingled with the crashes of trees and the wild cries of legions of birds of all kinds; which fell scorched and blackened and dead to the ground.’ W. Howitt (1856) describing the 1851 Victorian bushfires The immediate response to fire by birds depends on the extent, speed and intensity of the fire; habitat; and species of bird. It is likely that many birds take action well in advance, and depart or seek shelter. Some birds are overcome by the heat, smoke or flames, and their nests may be destroyed. More mobile species tend to fare better, though some terrestrial species take refuge in wet areas, burrows and logs. Other birds, including some raptors, insectivores and seed-eaters, are attracted to fire and its charred results, moving in from adjacent habitats or drawn from far and wide by the smoke. This is particularly so in the north, where Black and Brown Falcons, Black and Whistling Kites, Australian Bustards, woodswallows and Tree Martins often arrive in large numbers to feed on flushed, killed or injured animals. Granivores, including Gouldian Finches, exploit seeds exposed by the fire. After a relatively short time they move on, sometimes to the next fire. By contrast, in temperate areas a more successional colonisation of the burnt areas occurs and the initial post-fire scene is often one with few birds. 5 Maintaining fire-free habitat fragments: Helmeted Honeyeater A number of colonies of the critically endangered Helmeted Honeyeater (west Gippsland subspecies, also known as the Yellow-tufted Honeyeater) were destroyed by the Ash Wednesday fires—for example, those at Cardinia and Cockatoo Creeks. Thus, the remaining colonies, in streamside lowland swamp forest at Yellingbo, are maintained as essentially fire-free, although the Ranger has trialled small-scale burning to control the introduced grass Phalaris. BRUCE QUIN, Department of Sustainability and Environment, Victoria The first year ‘In the first year after the fire, the avifauna of burnt habitats differs from that which develops later, or which was present before the burn.’ John Woinarski & Harry Recher (1997) The reduction of food and cover for some resident bird species leads to starvation, predation or emigration. Species suited to more open habitats, mainly seed-eaters and insectivores, may move in temporarily, from adjacent areas or further afield, to take advantage of a flush of insects and seeds generated by the quickly responding growth of grasses and flowering annuals. Examples include: Straw-necked Ibis; Torresian Crow; butcherbirds; Red-tailed Black-Cockatoo; Galah; quail; nightjars; Red-backed Kingfisher; Partridge Pigeon and several finch species in the north; Scarlet and Flame Robins; and Buff-rumped Thornbills in the south. These species move on or their numbers thin out as regeneration progresses. Cumulative impacts: the Black-eared Miner The Black-eared Miner numbers less than 450 breeding individuals. Its habitat is mallee that has been unburnt for 20 or more years, where it reaches highest densities 40 or more years since burning. Much of its former habitat in the Murray Mallee has been cleared for agriculture. Yellow-throated Miners have colonised man-made clearings within intact mallee and are interbreeding with the Black-eared Miners, swamping most populations except at Bookmark Biosphere Reserve. Hybridisation and fire are now the major threats to the species’ survival. MICHAEL CLARKE, La Trobe University, Victoria Later years ‘The pattern and rate of change in species abundance following fire differs according to habitat, floristics, fire history, climate, patch size and isolation and patchiness of the fire.’ John Woinarski & Harry Recher (1997) The land area of Australia burned in the last five years. Map prepared by Cameron Yates and Brian Lynch (NT Department of Infrastructure Planning and Environment), from information supplied by WA DOLA. As regeneration proceeds, species present before the fire begin to return or build up; most populations recover within three to ten years, while a few take decades to return to pre-fire levels. Periods of low rainfall may slow the recovery of vegetation and return of birds. In habitats typically slow to regenerate, such as old-growth forest, their characteristic species—e.g. hollow tree nesters and canopy feeders—may still be absent or less abundant 50 years after an intense fire that kills canopy trees. FIRE SEASONS Fires in the mallee can create flushes of food for the Malleefowl, but it needs long-unburnt country to breed. Photo by Lynn Pedler DARWIN TENNANT CREEK PORT HEADLAND MT ISA ALICE SPRINGS Tarawi Nature Reserve fire management plan BRISBANE GERALDTON KALGOORLIE PERTH SYDNEY CANBERRA ADELAIDE MELBOURNE Winter and spring Spring Summer Spring and summer Summer and autumn HOBART The timing of the main fire seasons reflects the different weather patterns. Note the tendency for summer/autumn to be the danger period in the southern States, and winter/spring in the north. Source: www.bom.gov.au Tarawi Nature Reserve is in the semi-arid mallee of New South Wales. The key elements of the Reserve’s fire management plan put into practice much of the new knowledge in conservation science. General conservation goal: to manage fire to minimise the risk of any native species becoming extinct. Objectives: • ensure consecutive fires are at least 20 years apart in any one area; • ensure a range of post-fire ages are present in the reserve (at least 50% of each mallee community should be >40 years old) to promote patchiness in wildfires, although a scale of patchiness is not specified due to lack of knowledge; • determine the biodiversity values of long-unburnt mallee (>70 yrs); • burn strategically to contain the spread of wildfires that may violate the thresholds for fire frequency, post-fire age diversity or patchiness requirements. Extracted from Keith et al. (2002) 4 Fire and Birds Fire and Birds Responses of birds to a single fire event The effects of a fire on bird communities can be difficult to predict. They vary with fire intensity, season and extent; the characteristics of the site, climatic variation before and after; and time elapsed since fire. Species differ in their response to fire and individual species vary in their response. In general, the Australian bush and its wildlife can cope with single fire events, but over time frequent, widespread fires change the character of the landscape and its inhabitants, to the detriment of fire-sensitive species. Before, during and after Flame Robin. Photo by Peter Merritt Large logs can act as micro fire-breaks, adding desirable heterogeneity to the habitat, and they offer refugia for animals in their moist interior. Regrowth in the early succession stages after fires, particularly in the south of the country (here Tiajara, NSW), attracts small insect-eaters such as Scarlet and Flame Robins. Photo by Graeme Chapman Some definitions Backburning: a fire that is intentionally lit to consume fuel in the path of a wildfire. Bushfire or wildfire: a general term used to describe a fire in native vegetation. Prescribed, controlled, fuel reduction, or planned burning: a fire lit under specified (i.e. relatively safe) environmental and weather conditions to burn over a predetermined area, at a time, intensity and rate of spread necessary to achieve particular management objectives. Fire-break: any natural or constructed discontinuity in fuel used to break up, stop or control the spread of a fire. Fire age: the time elapsed since the last fire. Fire intensity: the amount of energy released per unit length of the fire front, usually expressed as kilowatts (kW) per metre. Fire regime: the history of fire in a particular area, comprising the frequency, intensity, season of burning (i.e. the time of year a fire occurs) and the type. Type: refers to whether the fire is above-ground or below-ground (i.e. a peat fire), but as almost all fires in Australia are aboveground this component is usually irrelevant. Fire succession: the series of stages that vegetation goes through in its recovery post-fire. Fuel load: the amount of combustible material, especially easily ignitable material. Hazard reduction burn: a fire intentionally lit to reduce the amount of fuel, and consequently reduce the risk posed by wildfires. Fuel is any material, such as bark, leaf litter and living vegetation, which will burn. Trittering: mowing and mulching which involves pulverising the leaf litter so that it becomes compacted and burns more slowly with a reduced flame height. Adapted from the NSW National Parks & Wildlife Service Fire Management Manual (2001) policy and management (see ‘Bushfire management in the Northern Territory’ p. 16, ‘Tarawi Nature Reserve’ p. 5). Recent legislation in most Australian States and Territories not only requires that fire is managed by land managers in fire-prone vegetation, but that it is used in ecologically sustainable ways. The importance of periodic prescribed fire (controlled burns) to increase or maintain biodiversity is now widely accepted. Insights from Indigenous experience can help inform the development of effective fire management practices. Sadly, much of this knowledge has been lost or eroded. More importantly, landscapes are now substantially modified from those managed by Indigenous Australians—by weed invasion, introduced grasses, grazing, clearing and drainage; and reduced, fragmented habitats. These factors can dramatically alter fire impacts on landscapes and ecosystems. ‘I am confident that the indiscriminate burning of bush, which is the concomitant of all farming and grazing operations, is by a long way the major cause of the disappearance of many of our rarer birds.’ Edwin Ashby (1924) The environmental impacts of fire on natural ecosystems are not well understood due to the complexity of the problem, paucity of research, and megadiversity of the Australian landscape. There are few detailed long-term studies of the effects of fire on avian communities, but there is sufficient information on fire effects from a broad cross-section of Australian habitats to identify patterns of response to individual fires (see ‘Responses of birds to fire’ p. 5) and predict likely long-term effects. Depending on the severity of the fire, the amount of vegetation burned and killed, and the weather during the recovery period, most avian communities recover rapidly following single fires regardless of fire intensity. However, even single fires may pose a significant threat to species with restricted distribution, limited reproductive potential, poor dispersal ability and/or narrow habitat requirements. Birds persisting in fragmented habitats are particularly at risk because the whole fragment can burn and, post-fire, small fragments may not be recolonised by all of their original species. Nonetheless, far more threatening across a broad range of avian communities, are increases in fire frequency and extent, on the one hand, and fire exclusion on the other. These tend to homogenise the landscape, and offer fewer options for survival and recolonisation. Detrimental fire regimes have contributed to the extinction of two of the three bird species, and three of the four subspecies, lost since European colonisation. Inappropriate fire management is now a factor in the threatened status of over 50 nationally recognised threatened bird species (see table p. 6). Of those threatened species whose relationships with fire have been welldocumented, almost all show a preference for less frequent, less extensive fires than have occurred in recent decades. Though the task is daunting, the costs of inaction are great. Fire can be an economical way to manage large tracts of land, on a fine scale, with benefits to biodiversity and human needs. The challenge will be to identify and develop the appropriate fire regimes to maintain fire-dependent habitats and protect the fewer fire-sensitive habitats. The single greatest need for land managers incorporating fire into their management is a useful tool to determine appropriate fire regimes (see ‘To burn or not to burn’ and ‘Towards a set of biodiversity-friendly fire management principles’ p. 6). ‘There was a sound as of thunder, mingled with the crashes of trees and the wild cries of legions of birds of all kinds; which fell scorched and blackened and dead to the ground.’ W. Howitt (1856) describing the 1851 Victorian bushfires The immediate response to fire by birds depends on the extent, speed and intensity of the fire; habitat; and species of bird. It is likely that many birds take action well in advance, and depart or seek shelter. Some birds are overcome by the heat, smoke or flames, and their nests may be destroyed. More mobile species tend to fare better, though some terrestrial species take refuge in wet areas, burrows and logs. Other birds, including some raptors, insectivores and seed-eaters, are attracted to fire and its charred results, moving in from adjacent habitats or drawn from far and wide by the smoke. This is particularly so in the north, where Black and Brown Falcons, Black and Whistling Kites, Australian Bustards, woodswallows and Tree Martins often arrive in large numbers to feed on flushed, killed or injured animals. Granivores, including Gouldian Finches, exploit seeds exposed by the fire. After a relatively short time they move on, sometimes to the next fire. By contrast, in temperate areas a more successional colonisation of the burnt areas occurs and the initial post-fire scene is often one with few birds. 5 Maintaining fire-free habitat fragments: Helmeted Honeyeater A number of colonies of the critically endangered Helmeted Honeyeater (west Gippsland subspecies, also known as the Yellow-tufted Honeyeater) were destroyed by the Ash Wednesday fires—for example, those at Cardinia and Cockatoo Creeks. Thus, the remaining colonies, in streamside lowland swamp forest at Yellingbo, are maintained as essentially fire-free, although the Ranger has trialled small-scale burning to control the introduced grass Phalaris. BRUCE QUIN, Department of Sustainability and Environment, Victoria The first year ‘In the first year after the fire, the avifauna of burnt habitats differs from that which develops later, or which was present before the burn.’ John Woinarski & Harry Recher (1997) The reduction of food and cover for some resident bird species leads to starvation, predation or emigration. Species suited to more open habitats, mainly seed-eaters and insectivores, may move in temporarily, from adjacent areas or further afield, to take advantage of a flush of insects and seeds generated by the quickly responding growth of grasses and flowering annuals. Examples include: Straw-necked Ibis; Torresian Crow; butcherbirds; Red-tailed Black-Cockatoo; Galah; quail; nightjars; Red-backed Kingfisher; Partridge Pigeon and several finch species in the north; Scarlet and Flame Robins; and Buff-rumped Thornbills in the south. These species move on or their numbers thin out as regeneration progresses. Cumulative impacts: the Black-eared Miner The Black-eared Miner numbers less than 450 breeding individuals. Its habitat is mallee that has been unburnt for 20 or more years, where it reaches highest densities 40 or more years since burning. Much of its former habitat in the Murray Mallee has been cleared for agriculture. Yellow-throated Miners have colonised man-made clearings within intact mallee and are interbreeding with the Black-eared Miners, swamping most populations except at Bookmark Biosphere Reserve. Hybridisation and fire are now the major threats to the species’ survival. MICHAEL CLARKE, La Trobe University, Victoria Later years ‘The pattern and rate of change in species abundance following fire differs according to habitat, floristics, fire history, climate, patch size and isolation and patchiness of the fire.’ John Woinarski & Harry Recher (1997) The land area of Australia burned in the last five years. Map prepared by Cameron Yates and Brian Lynch (NT Department of Infrastructure Planning and Environment), from information supplied by WA DOLA. As regeneration proceeds, species present before the fire begin to return or build up; most populations recover within three to ten years, while a few take decades to return to pre-fire levels. Periods of low rainfall may slow the recovery of vegetation and return of birds. In habitats typically slow to regenerate, such as old-growth forest, their characteristic species—e.g. hollow tree nesters and canopy feeders—may still be absent or less abundant 50 years after an intense fire that kills canopy trees. FIRE SEASONS Fires in the mallee can create flushes of food for the Malleefowl, but it needs long-unburnt country to breed. Photo by Lynn Pedler DARWIN TENNANT CREEK PORT HEADLAND MT ISA ALICE SPRINGS Tarawi Nature Reserve fire management plan BRISBANE GERALDTON KALGOORLIE PERTH SYDNEY CANBERRA ADELAIDE MELBOURNE Winter and spring Spring Summer Spring and summer Summer and autumn HOBART The timing of the main fire seasons reflects the different weather patterns. Note the tendency for summer/autumn to be the danger period in the southern States, and winter/spring in the north. Source: www.bom.gov.au Tarawi Nature Reserve is in the semi-arid mallee of New South Wales. The key elements of the Reserve’s fire management plan put into practice much of the new knowledge in conservation science. General conservation goal: to manage fire to minimise the risk of any native species becoming extinct. Objectives: • ensure consecutive fires are at least 20 years apart in any one area; • ensure a range of post-fire ages are present in the reserve (at least 50% of each mallee community should be >40 years old) to promote patchiness in wildfires, although a scale of patchiness is not specified due to lack of knowledge; • determine the biodiversity values of long-unburnt mallee (>70 yrs); • burn strategically to contain the spread of wildfires that may violate the thresholds for fire frequency, post-fire age diversity or patchiness requirements. Extracted from Keith et al. (2002) 6 Fire and Birds Fire and Birds Towards a set of biodiversity-friendly fire management principles South-eastern Red-tailed Black-Cockatoos and Fire The endangered South-eastern Red-tailed BlackCockatoo is a dietary specialist; it eats only the seeds of three tree species—Brown Stringybark, Desert Stringybark and Buloke. Supplies of these seeds are patchy in space and time, and flocks tend to concentrate on the seed stocks that can be most efficiently harvested. There is mounting evidence that cockatoo breeding success is related to the availability of fresh stringybark seed crops. The stringybark forests of south-western Victoria are highly flammable and the heathy understorey requires fire to maintain its floristic diversity. However, fires that burn or scorch the canopy result in reduced seed production for up to nine years. Therefore, the widespread burning of stringybark forests through the twentieth century may have been a cause of population decline in the Red-tailed Black-Cockatoo. With this in mind, a moratorium on burning was imposed in 1989. However, there are now good ecological and asset protection reasons for resuming planned burns. In an attempt to resolve this impasse, the Department of Sustainability and Environment, with the support of the recovery team, has trialled methods of burning the understorey while minimising canopy scorch. This is a tall order in stringybark forests, where the fibrous bark tends to carry flames upwards. However, given the right conditions of fuel moisture and weather, the trials are suggesting that ecological burning aims, or asset protection aims, can be met whilst minimising the impact on future crops of stringybark seed. PETER MENKHORST AND JIM MCGUIRE, Department of Sustainability and Environment, Victoria Australia is a large and diverse country, hence there are many views and requirements for biodiversity-friendly fire management. The following are some of several recommendations in the literature: • Encourage precautionary fire management. • Be aware that fire regimes need to be local and focus on particular objectives. • Wherever possible develop guidelines and prescriptions for landscapes and biological communities, not individual plants and animals. • However, where there are species or groups of species that are susceptible to decline under certain fire regimes, fire management regimes should be framed around their needs. • Aim for fire management targets that are ranges rather than optima; for example, rather than choosing the best time for one species pick a range of times and fire intervals that cover several species. • Avoid fire regimes known or suspected to result in loss of biodiversity in the same or related ecosystems. • Be aware that fire frequency is a key element of fire management—with few exceptions both fire exclusion and short intervals between fires over a broad area are damaging to biodiversity. • Similarly, broadscale, intense fires are damaging to heterogeneity of habitats • • • • • • • • across the landscape, and hence to biodiversity values. Hence, aim to reduce the extent of land/ proportion of vegetation community burned in single-fire events, no matter what time of year that happens. Use fire at a small scale to promote spatial and temporal variability in fire regimes across the landscape, that is, a patchwork of areas of different fire-ages and histories. Understand that fire-generated patchiness is good but must be at the right scale (for example, in relation to the species being managed or the size of the remnant). Develop prescriptions to limit the extent and spatial invariability of fires by controlling fire behaviour, rather than by imposing artificial exclusion zones and intervals between fires. Accept that there will always be gaps in knowledge, which introduce an element of uncertainty in the decision-making process. Allow for unplanned fires. Climate change means that the country is likely to be entering a period of hotter, drier conditions, which will produce more extreme fire events, which will need to be factored into management. Apply adaptive management, including monitoring, to inform decisions and improve management. Threatened birds and fire regimes. This table presents some simple rules for bird-friendly fire management1. Local conditions and threatened species should be used as a finer guide to management. To burn or not to burn Fire regimes result from complex interplay between biotic (e.g. fuel loads) and abiotic factors (e.g. weather conditions), increasingly overlaid with human decisions in support of a variety of land uses, including biodiversity conservation. Land managers must weigh up these factors to estimate the threat from uncontrolled fire and the desirability of a controlled burn. contours slope fire history vegetation land cover fuel loadings McArthur Fire Model Main habitat Threatened species for which inappropriate fire management is a threat2 Current general fire problem for bird conservation Fire management for bird conservation Coastal and sub-coastal shrublands Orange-bellied Parrot CE Ground Parrot (eastern) V Ground Parrot (western) CE Rufous Scrub-bird (northern) V Noisy Scrub-bird V Southern Emu-wren (Fleurieu Peninsula) CE Southern Emu-wren (Eyre Peninsula) V Eastern Bristlebird (northern) CE Eastern Bristlebird (southern) E Western Bristlebird V Rufous Bristlebird (Otways) V Western Whipbird (western heath) V Too frequent burning; too coarse a mosaic. Pattern: Fine mosaic of areas of different fire-ages with a bias towards retention of older fire ages. Intensity: Low. Mallee Malleefowl V Mallee Emu-wren V Black-eared Miner E Western Whipbird (eastern) E Fire management (prescribed burns or Aboriginal burning regimes) has been much reduced so that wildfires are too hot and extensive. Pattern: Mosaic of areas of different fire-ages with a bias towards retention of older fire ages. Fire frequency at most every 40 years in any particular area. Intensity: Low. Temperate eucalypt open forests Red-tailed Black-Cockatoo (south-eastern) E Glossy Black-Cockatoo (Kangaroo Island) E Helmeted Honeyeater CE [riparian] Forty-spotted Pardalote E Fire exclusion. Pattern: Mosaic of fire-ages across the landscape with a bias towards retention of older fire ages. Intensity: Flexible use of a broad range of fire regimes. Tropical and sub-tropical forests/ rainforest Southern Cassowary V Red Goshawk V Black-breasted Button-quail V Masked Owl (Tiwi Islands) E Fire exclusion permits spread of fire-sensitive species. Pattern: Mosaic of fire-ages across the landscape with a bias towards retention of older fire ages. Intensity: Occasional hot burns. Tropical and sub-tropical savanna woodlands and grasslands Buff-breasted Button-quail E Partridge Pigeon (western) V Golden-shouldered Parrot E Paradise Parrot Ex Night Parrot CE Hooded Robin (Tiwi Island) V Crested Shrike-tit (northern) E Gouldian Finch E Star Finch (Cape York) E Fires now too hot, extensive and frequent, or, alternatively, too infrequent. Pattern: Fine-scale mosaic of fire-ages across the landscape, with between 10 and 30% of landscape burned each year. Intensity: Occasional hot burns. Wetlands Australian Bittern (Australasian) V Burning of habitat to create pasture. No prescribed burns. standard fuel & weather conditions Hazard structures roads and trails residential Risk revegetation residential structures constructed values fauna values flora values natural values Risk/Hazard matrix Values Threat One approach to the prediction of the threat of fire. Source http://www.planning.sa.gov.au 1Based on information in Woinarski (1999) www.deh.gov.au/biodiversity/publications/technical/fire/ from Garnett & Crowley (2002). Categories of threat in decreasing order of severity: Ex = Extinct; CE = Critically Endangered; E = Endangered; V = Vulnerable; subspecies name in brackets. Twenty-two other species are listed as Near Threatened, and inappropriate fire regimes are among their major threats. 2Extracted 7 LIVING WITH FIRE—BIRDS IN NORTHERN AUSTRALIA Australia’s north is a landscape of fire, and some naive ideal of fire suppression and exclusion will neither work nor suit most bird species by John Woinarski Climatic conditions, vegetation, social factors and human population dispersion cause fire to be a very different phenomenon in northern Australia to that elsewhere in the continent. The north is monsoonal, with a strongly seasonal climate marked by a long, almost rainless, warm dry season (typically from about April to October), and a strongly contrasting hot wet season. Fire is an inevitable part of this landscape. The dense, tall grasses grow rapidly over the short wet season, and then dry out over the long dry season, becoming highly flammable. Without human intervention, this vegetation burns readily with ignition from lightning strikes, a characteristic feature of the first thunderstorms that mark the transition from the dry to the wet. Humans have long been moulding this landscape. For the Indigenous people fire has been a crucial part of life and their main management tool for 40,000 years or more. Such application of fire was far from reckless. The consequences of ill-advised fire management were severe: vital food sources could be eliminated through inappropriate fires, and fires that spread to burn neighbouring clan estates could invite retribution. In parts of northern Australia this tradition continues. In these areas, the application of fire may be a highly skilled and carefully considered operation, carried out diligently throughout the year. Typically, this traditional management involves many small ‘cool’ fires, producing an intricate network: a fine-scale mosaic of unburnt patches and patches burned at different times through the year. Often, the more fire-sensitive components of the landscape—such as rainforest patches—were explicitly and deliberately protected from fire, typically by burning around their margins. These elements were valued because they produced important foods, particularly yams, in traditional diets; and the maintenance of such fire-sensitive elements in a clan estate was a sign of proper management. Over the last century, traditional Indigenous fire management in most of northern Australia has broken down. Indigenous people were dispossessed from much of the landscape. Even in lands that maintained Indigenous ownership, population dispersion and lifestyles changed. In the decades around the Second World War, most of the population moved off their clan estates to live at mission stations and other townships. In some areas, this dynamic has been reversed through the ‘outstation movement’, beginning in the 1970s. But, over most of northern Australia, traditional burning has been disrupted and replaced by very different fire regimes. Below left: With less than 50 known individuals the Eastern Bristlebird (northern subspecies), of Cooloola National Park and the Conondale Ranges, Queensland, is critically endangered. Its main threat is changed fire regimes, with fire now too frequent, destroying the species’ tussock grass habitat, or too infrequent, allowing shrubs to become too dense. Below: Fires remove dense ground cover to expose seeds on which the finches feed, but may also destroy wet season food species, and nests. Here a Masked Finch collects charcoal for its nest (presumed to help keep the nest dry and sanitised). Photos by Graeme Chapman Wildfire at Kakadu National Park, Northern Territory. Photo by Raoul Slater Fuelling fire The current fire regimes vary somewhat between tenures. On pastoral lands, which occupy about half of northern Australia, fire is generally unwanted and suppressed—livestock consume most of the grassy fuels, so that fire behaviours and intensities are now different to those that prevailed over tens of thousands of years. Partly because of the reduced incidence of fires, vegetation in many pastoral areas is changing, often with increases in the density and extent of woody shrubs and decrease in grassland areas (‘vegetation thickening’). Fires on other tenures are now characterised by an increased incidence of late dry season burns, and these are typically more intense and extensive. The previous fine mosaic of patchy burnt and unburnt areas has been replaced by broad-scale conflagrations that homogenise the landscape. Far more often than previously, these fires engulf the fire-sensitive elements of the landscape. Superimposed on this change in fire regimes is the consequence of the increasing and largely uncontrollable spread of African and South American pasture grasses, deliberately introduced by pastoralists and pasture scientists to transform (‘improve’) the landscape. This insidious set is marked by their ability to dominate almost every environment in northern Australia, including wetlands (Para Grass, Olive Hymenachne), tropical open forests and savanna woodlands (Gamba Grass, Mission Grass, Guinea Grass) and semi-arid woodlands (Buffel Grass). The replacement of native understoreys by introduced pastures is itself an ecological wound but, worse, these grasses also greatly alter fire regimes. Largely because they are voracious consumers of soil nutrients, exotic grasses produce fuel loads that are far greater than native grasses (up to seven times the biomass), and they typically cure later in the dry season. This inevitably means that fires fuelled by exotic, invasive pastures are more intense (up to 10 times hotter) than fires with native grass understoreys. Whereas previously fires in northern Australia burned the grassy understorey and rarely affected the tree layer, exotic grasses are now fuelling crown fires that kill the tree layer. Currently, fires burn about 30–50% of northern Australia each year. Many areas have been burnt every year over the last decade. The scale and recurrence of fires is vastly different to southern Australia. In extent, the regular fires of northern Australia dwarf the bushfires in south-eastern Australia, such as Ash Wednesday and those in the south-east highcountry in 2003. For example, in five days of October 2004, a fire in the Sturt Plateau and northern Tanami Desert of the Northern Territory burned out an area greater in size than Tasmania, but didn’t even make headlines in the local newspapers.