Bats resilient to wildfire, study finds

March 7, 2013

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Antrozous pallidus, pallid bat (picture by Winifred Frick)

A study of bat activity in burned and unburned areas after a major wildfire in North America has found no evidence of detrimental effects on the bats one year on from the fire.

According to a Murdoch University researcher who co-authored the study, the findings have relevance anywhere fire occurs and that bats in the jarrah forest of Western Australia are likely to be resilient as well.

Fire ecologist Dr Joe Fontaine from the School of Veterinary and Life Sciences said WA bats could utilise recently burned areas to find food. In the North American study, he said some species seemed to prefer burned areas for foraging possibly because of reduced clutter and increased availability of prey and roosts.

“Currently however little research exists into the effects of wildfires on bats and learning more about such an ecologically important group of animals should be a future priority,” said Dr Fontaine.

“Bats make up a large component of mammalian diversity in all forest ecosystems, where they play an important role as insect predators.

“The findings of our study are important wherever there are wildfires because our current understanding of how wildlife responds to fire is based almost entirely on studies of a limited number of species, most of them birds.

“Research such as ours helps to inform the ongoing public policy debate over the role of fire in ecosystem management and whether fires should be suppressed or allowed to burn on publicly owned lands.”

Dr Fontaine worked with bat ecologist Winifred Frick of the University of California, Santa Cruz, Michael Buchalski of Western Michigan University, Paul Heady of the Central Coast Bat Research Group and John Hayes of the University of Florida, to find that some bats in the Southern Sierra Nevada mountains in California may even benefit from the effects of fire on the landscape.

The researchers conducted the study in an area of Sequoia and Inyo National Forests where the 2002 McNally Fire burned more than 60,000 hectares. The fire burned with mixed severity, leaving a mosaic of low-to-high severity damage, as well as patches of unburned forest. The study compared bat foraging activity in areas of unburned, moderately burned, and severely burned forest.

The researchers conducted surveys in 2003, using high-frequency microphones to record the ultrasonic echolocation pulses that bats use to hunt insects. Of the 16 bat species known to live in the area, some have distinctive sonic signatures, while others can be sorted into groups with similar echolocation sounds and foraging behaviours. In this study, the researchers identified six "phonic groups," including three individual species and three groups of species.

The results showed that the responses of the six phonics groups to moderate and high-severity fire were either neutral or positive.

“Fire may produce a pulse of insects immediately after the fire and create roosting habitat as snags decay and their bark peels back,” added Dr Fontaine.

The study, entitled Bat response to differing fire severity in mixed-conifer forest California, USA, was published in the journal PLOS One.

Comments (2 responses)

David Rastrick March 12, 2013

This valuable research on bats may or may not be of relevance to West Australian Jarrah forests. The Old Climatically Buffered eco-systems of South-West Australia are likely to be very different to the Relatively Young Often Disturbed ecosystems of North America.

Joe Fontaine March 12, 2013

Indeed there are profound differences between the jarrah forests of SW Australia and the mixed-conifer forests of California's Sierra Nevada mountains (too many to list!). I think critical similarities have more to do with the bats and their ecology than the vegetation itself.

Bats tend to like less cluttered environments (easier to forage) and also likely respond positively to the post-fire pulse of productivity driving insect abundance up. This is particularly marked along watercourses. Dynamics of roosting habitat probably are different given that fire may kill conifers but rarely large Eucalypts like jarrah, marri, or wandoo.

Finally, the role of fire in maintaining or generating heterogeneity at the landscape scale may be quite similar; bats often forage across broad areas taking advantage of varying conditions to find food and roosting opportunities.

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