Fire plays an important role in shaping the habitat of many animal species. Some animal species benefit from regular firing of their habitat whilst others are disadvantaged. For example the New Holland mouse, which lives in coastal heathland, increases in numbers soon after a fire has occurred. This is because seeds, the primary food source for this mouse, are released by many heathland plants after fire. Hence a fire regime of 5-10 years is considered optimal for this mouse. However, if another fire occurs before the new plants mature and produce seed this could lead to the disappearance of the New Holland mouse.
The threatened pencil pine moth, on the other hand, is dependent on the pencil pine which is highly vulnerable to fire. Fire kills pencil pines and hence removes the moth's only habitat.
In general fire sensitive plant communities will contain fire sensitive animal communities and fire tolerant plant communities will contain fire tolerant animal communities. However, even in those plant communities that require regular burning there will be animals that require differing fire regimes.
Fire can also create a rejuvenated habitat for many species. Herbivorous mammals are known to like the fresh pickings associated with the regrowth that follows fire. Species such as the bettong, which prefer relatively open understoreys, are advantaged by fire because open understoreys are maintained by fire.
Fires in Buttongrass Moorlands
Within a year after buttongrass moorland has been burnt the vegetation starts to regrow, producing succulent shoots that attract herbivorous animals such as Bennetts wallabies, wombats and grasshoppers. However, these species, particularly wallabies and wombats, require nearby areas of unburnt habitat were they can shelter.
Small mammals such as the swamp rat, broad-toothed mouse and swamp antechinus cannot survive in recently burnt buttongrass moorland as there is very little cover to provide protection from predators. They may have to wait five years or more before they can move back into the regenerating moorland as the vegetation grows and thickens.
Recent research suggests that broad-toothed mice may re-colonise buttongrass moorland sooner than swamp rats. The reasons for this are not known. Swamp rats are omnivorous and it may take longer for a sufficient range of foods to be available to them. Broad-toothed mice are totally herbivorous and presumably can feed on regrowth once there is sufficient cover from predators. Swamp rats may also require a greater vegetation cover for nesting sites or protection from predators.
Among bird species, the critically endangered orange-bellied parrot prefers buttongrass moorland habitat which has been burnt within the past 12 years, while ground parrots prefer a period of greater than 5 years between fires.
The effect of fire on invertebrate populations is less well known. One study suggests that the diversity of arthropods in buttongrass moorlands is best suited to a burning regime with a minimum of five years between burns, and that the optimum interval between burns is 20 years. The rare Hickman's pygmy mountain shrimp (Allanaspides hickmani) lives in pools in buttongrass moorlands. If a fire in moorland is very intense and burnt into peat, this threatened species may also be affected.
Where do animals go when a fire comes?
Animals are generally very good at surviving fires, although an exceptionally intense fire can lead to the wide scale loss of individuals. Arboreal mammals, such as pygmy possums and sugar gliders, can be killed by intense fires as these fires burn the canopy of the trees where they live.
Some animals may survive a fire but then succumb to the loss of food, protective cover and nesting material. Smaller animals are also more vulnerable to predation after a fire. As the vegetation recovers from fire, new opportunities arise for some species.
Less intense fires pose a much smaller risk to animals. Highly mobile species are able to move out of danger while birds and other flying species, of course, can simply fly away. Burrowing animals, such as the wombat, are able to survive within their burrows. Similarly, some invertebrates can shelter underground. Hopping mammals such as Bennetts wallabies can travel through breaks in the fire front.