Untapped potential for animals to help reduce bushfire risk

17 April 2020

A new study led by The Australian National University (ANU) has found that animals may be an "untapped" resource to help manage fuel loads for bushfires. 

Lead author Dr Claire Foster said Australia's recent summer has shown that wildlife can be severely impacted by bushfires, but the report found that animals can also influence bushfires in surprising ways.   

"Large grazing animals - including cows, kangaroos and rhinos - eat large amounts of grass, and by doing so can reduce the size and spread of grassland fires," said Dr Foster from the ANU Fenner School of Environment and Society.  

"In other environments, the activities of smaller animals, such as a mallefowl building nests, bettongs digging for food or even insects eating fallen leaves can also have important effects on the fuel that bushfires burn. 

"Conserving and restoring populations of these animals might have two benefits - the conservation of the species themselves, and keeping fuel amounts low in the forests and woodlands they live in."  
 
Dr Foster said events like the most recent bushfire season and the COVID-19 pandemic could reduce animals' positive contribution to reducing fuel loads. 

"If populations of these animals don't recover from events like this summer's widespread bushfires, that could have long-term consequences for future fire risk," she said. 

"One thing I am concerned about at the moment is the impact of the COVID-19 crisis on conservation and monitoring efforts in Australia. Many conservation scientists have had to shut down or significantly reduce their fieldwork at what is a critical time for the recovery of wildlife populations." 

Dr Foster warned against over-stating the role that fuel, and hence animals, plays in fire behaviour.  

"Fuel can have a strong influence early in a fire, and under moderate fire conditions. But catastrophic mega-fires are largely driven by weather and drought conditions," she said. 

"However, reducing fuel loads is certainly an important part of authorities' bushfire management strategies."  

Grass-eating mammals such as cows, sheep and kangaroos, can be useful to help manage fuel in grassland ecosystems, Dr Foster said.  

"In some parts of Australia, cows are regularly used to keep fuel levels down in grassland reserves. But our report has shown that grazing animals don't always have the expected effect of suppressing fires," she said. 

"What's important to consider is not just what these grazing animals eat, but also what they choose not to eat. In some environments, such as in alpine areas or forests, livestock will eat some grasses and herbs but leave behind other plants like shrubs and tree seedlings."  

Over time, a grassland might become a shrubland, which can be a much more challenging proposition for firefighters, Dr Foster said. 

"A key message of our report is that land managers should consider how the animal will affect fuel structure and condition - which includes moisture and chemical content - not just the amount of fuel." 

The research is published in Trends in Ecology and Evolution and is available at:  https://authors.elsevier.com/a/1alBVcZ3WnzGD