Fire, Science and Biodiversity at Jervis Bay
Anyone who has visited Booderee National Park at Jervis Bay on the NSW south coast will have marvelled at its stunning white beaches, rugged hills, forests, woodlands, heaths, swamps and marshes. Its varied landscapes support a range of precious ecosystems and an impressive number of native animals and plants, many of which are threatened. It’s a birdwatcher’s paradise. What’s not so apparent on first view, however, is the important role that fire has played in sculpting and sustaining these ecosystems. In recent years, ecologists from ANU have been playing a pivotal role in understanding this rich tapestry of fire and nature, and their work is playing a crucial role in managing the unique values of this area.
“Fire is a major natural ecological process that influences and shapes Australian ecosystems and the native wildlife that inhabit them,” says Professor David Lindenmayer, the scientist in charge of the Jervis Bay Fire experiment. “Managing fire is also a hotly contested debate. Fires in eastern Australia in recent years have resulted in many commentators calling for more frequent and widespread use of fires to reduce fuel loads. It’s argued that such practices will reduce the occurrence and intensity of wildfire, and assist in fire control. But the impacts of fire on biota is complex and not well understood. What is known is that inappropriate fire regimes have contributed to the extinction of two species and three subspecies of birds, and are a major threat to more than 50 other bird species, and nearly 20 plant species.
“To inject a little hard science into this debate we’ve established a project in Booderee National Park which studies the long term effects of fire on the mammals, birds and reptiles inhabiting a range of vegetation types found in the park. The key aim is to quantify changes in vertebrate biota within vegetation types subject to alternate burning strategies.”
Within the park there are a total of 134 monitoring sites representing different types of vegetation, different fire histories and different prescriptive burning regimes. At each site, a permanent transect has been established, with 6 pitfall traps connected by drift fences. The program represents one of the largest pitfall and drift fence studies established anywhere in the world. Elliot trapping coincides with pitfall trapping, and spotlight and bird surveys are also conducted at each of the sites.
Time between fires is one of the key variables determining the responses from native animals and plants. One of the big advantages of working in Booderee is its fire history has been well mapped so it has been possible to set up monitoring and different fire management treatments in four classes of time since last fire (0-10 years, 11-20 years, 21-30 years and > 30 years).
“This project is one of the few large-scale and long-term experiments on fire in Australia,” comments Professor Lindenmayer. “It’s unique in the way it addresses key issues across a broad and diverse range of vegetation types and groups of biota.”
Soon after the experiment was set up, a massive wildfire ripped through the park in late 2003 burning a large proportion of Booderee and a number of the newly constructed sites. What at first appeared to be a major set back, turned out to be a great opportunity as it enabled Professor Lindenmayer, and his team of researchers from the Fenner School of Environment and Society, to directly measure the faunal response to wildfire. Many animals survived the fire event, and live in the recovering vegetation.
“We’ve been monitoring native wildlife in Booderee over several years now,” explains Professor Lindenmayer. “One surprising result is that if you manage other threats to wildlife, like foxes, you enable many native species to bounce back quickly after wildfire.
“For example, half the park was burned by the wildfire in 2003, and it was expected that it might take many years before some of the fire sensitive species returned, if they returned at all. To our surprise, many of these species, like the eastern bristlebird, reappeared very shortly after the fire and returned to pre-fire population levels very quickly. We believe this happened not because of the absence or presence of prescriptive burning but because fox control is a high priority for park managers and low fox numbers allowed animals to recover quickly.”
A number of single species studies are also being undertaken in and around the fire study. Chris MacGregor is studying the home range, habitat use and nesting habits of the long-nosed bandicoot under different fire regimes. Damian Michael is investigating the spatial ecology of the little understood diamond python. Martin Westgate is looking at frog behaviour and habitat use while Felicia Pereoglou is working on the conservation biology of the threatened eastern chestnut mouse.
“Booderee is a wonderful natural laboratory for studying fire and nature,” says Professor Lindenmayer. “We work closely with the park managers and I believe our research is helping them in their day-to-day management roles as well as creating an important and lasting scientific legacy on how to best work with fire in Australia’s varied landscapes.”