Australia is an island continent with ecosystems renowned for their flammability, high endemism of plants and animals, the keystone role of marsupial herbivores and carnivores, ancient Aboriginal traditions of landscape burning, and more recently, extraordinarily high mammalian extinctions and irruptions of mammalian herbivores and carnivores introduced by Europeans.
There much debate about the causes and consequences of the recent extinctions in uncleared Australia landscapes. Several prominent theories have stressed, to differing degrees, the importance of change fire regimes following the breakdown of Aboriginal land management and the introduction of non-native herbivores and carnivores. Some of these theories have also highlighted the legacy effects of the initial impact of Aboriginal colonisation in the late Pleistocene, including the extinction of very large marsupial herbivores and carnivores, collectively known a ‘megafauna’.
It is possible that specific spatiotemporal patterns of landscape burning (pyrodiversity) influences habitat quality and hence mammal diversity and abundance. Recursively, pyrodiversity is reinforced by mammalian food webs via a range of ecological processes (such as nutrient cycling, soil turnover, plant regeneration and growth, plant species diversity because mammals affect ecosystems process via digging, trampling, phytomass off-take, seed and spore dispersal, and concentrating nutrients) all of which directly and indirectly influence fire regimes. Critically, humans are both keystone predators that regulate herbivores and affect pyrodiversity by controlling the frequency, extent and seasonality of landscape fire.
This human controlled food web – pyrodiversity hypothesis has substantial management implications for restoring ecosystems in the Anthropocene globally. While manipulating fire regimes, humans must simultaneously manage mammalian food webs, possibly by introducing new species to compensate for the extinction of herbivorous and carnivorous vertebrates that have occurred recent and more distant past.