drawn to science22 February 2015
Meet Matt Swan, post-doctoral researcher with the School of Ecosystem and Forest Sciences at the University of Melbourne’s Creswick Campus. Matthew’s PhD asked: how does fire affect ground-dwelling mammals in the Otway Ranges?
Drive two hours southwest of Melbourne, and you’ll be in the heart of the Otway Ranges. The Otways span 140,000 hectares, and include the Great Otway National Park and the Otway Forest Park.
Matt Swan researched the mammals that call the Otway Ranges home for three years. He says, “I remember foolishly thinking at the start of my [PhD] project that I would learn to surf while doing field work.”
Surfing turned out to be a pipe dream – Matt’s field work was “physically and mentally exhausting” with early mornings and long days. Nonetheless, field work remains his favourite part of his PhD.
Matt says, “What’s not to like about the Otways? You’ve got great coastline abutting some of the best forests in the country. Ecologically it’s so diverse; in a short distance you go from low rainfall areas near Anglesea to the wettest area in Victoria further south.”
Matt’s PhD Research
Fire changes a landscape. A forest that was burnt last year will be vastly different to a forest that has not been burnt for 100 years. In ecology this is known as fire-mediated environmental heterogeneity or pyrodiversity for short.
Matt’s research asked whether there is a greater diversity of mammals where the landscape is more heterogeneous. He looked at how fire influences the distribution (spread) and abundance (number) of mammals in the Otway Ranges.
Matt’s research was part of a collaboration between Parks Victoria and the Victorian Department of Environment and Primary Industries (DEPI). A bevvy of academics and post-graduates are researching different aspects of the effects of fire regimes on biodiversity in the Otways. Other students are looking at plants, invertebrates, birds and feral predators.
Matt surveyed the mammals of the Otway Ranges each spring and summer for three years. “This involved physically trapping small species with Elliott traps and using wildlife cameras for larger species,” he explains. Matt sampled across places with different ‘fire histories’ – from very recent fires to areas that hadn’t been burnt for decades.
Fiery field work and feisty Antechinus
From antechinuses to kangaroos, Matt researched the entire ground-dwelling mammal community of the Otways. He recorded 17 native mammal species throughout his PhD including kangaroos, long-nosed potoroos and southern brown bandicoots. He says, “Many people don’t know it but the Otways has a really rich diversity of mammals.”
While some mammals are abundant (he caught more than a thousand bush rats during his PhD), other species are declining. Two species have become locally extinct in last couple of decades. Whether abundant or rare, Matt says, “It’s a privilege to work with creatures that almost no one gets to see up close.”
The Dusky Antechinus (pictured) is one of his favourite mammals. Matt describes them as a miniature grizzly bear. He jokes, “They definitely suffer from little animal syndrome. Whenever you caught one and they were in a bad mood they would hiss at you really loudly before trying to bite your finger off.” But part of their appeal was that they were uncommon. “It was nice to catch something that you didn’t run into every day.”
Matt also helped out with DEPI’s planned burns. He watched the “military sized” operation play out, and stepped in with a drip-torch to help. Matthew laughs that as a fire ecologist, he enjoyed being part of a planned burn – and that a drip torch is “good for bringing out your inner pyromaniac”.
So does pyrodiversity lead to biodiversity?
Different mammal species thrive in different stages of post-fire habitat. In ecological terms, heterogeneous environments provide a wide variety of resources for different species to exploit. So does this ‘patchiness’ lead to greater diversity of mammals?
Matt’s research found that patchy burns are beneficial for mammal diversity and survival. When a fire burns through an area, some mammals will flee to ‘refugia’ – unburnt patches of the landscape or areas, like damp gullies, that are unlikely to burn. Then eventually they disperse to the burnt areas once more.
The university’s “well-kept secret”
Since handing in his PhD early this year, Matt has been working as a post-doctoral researcher. Based at Creswick Campus, he is once again looking at the relationship between fire and biodiversity. Creswick is set among experimental forests of California Redwoods and English Oaks planted decades ago by the forestry school. It’s no Great Otways National Park but Matt says Creswick is a “well-kept secret” and well worth a visit.
Visit http://www.fireecologyandbiodiversity.com/ for more on Matthew’s research.