Cows and cremation – fighting fire with fire
By Jack Ashby, on 20 June 2011
In my last post I begun to talk about the Australian Wildlife Conservancy’s ecologists that I have joined for a month in the Kimberley region of northern Western Australia. It’s the dry season here and while most of the land isn’t underwater the annual ecological trapping survey is underway.
This involves trapping small mammals, lizards, snakes and frogs and doing bird and vegetation surveys to assess what lives in various different habitats here. A couple of major investigations are underway – the purpose isn’t just to create a list of residents. About half of the reserve has had cattle removed from it (because of seemingly bizarre land-leasing laws this conservation NGO is technically required to run their wildlife sanctuary as a cattle station), and one question is to ask what impact that has on the ecology. It’s easy to predict that the many small mammals that rely on grass seed would be affected by these massive grazers, and this is what the data are suggesting.
The investigation is only a few years old but fairly immediate response not related to grazing pressures is that pandanus, a palm-like plant that grows along creeks has spread significantly. Although cattle don’t eat pandanus they do kill it off by trampling it as they wallow in the rivers. It is now making a comeback here, and it brings with it the animals that live in it – threatened purple-crowned fairy wrens and buff-sided robins have risen sharply in numbers.
Today I have been doing something incredibly exciting related to another massive project AWC are working on – Ecofire. I’ve been in a helicopter over some of the most remote parts of the Kimberley dropping incendiary devices out of the door to start fires.
Burning huge tracts of wilderness might not appear to be at the heart of conservation but it has the potential to have a massively positive impact. After Europeans first started claiming this country and aboriginal management came to a stop, the way the land burnt changed drastically. Before Europeans, aborigines regularly burnt the savannas for a variety of reasons including making hunting and traveling easier. This left a patchwork of habitats of varying ages since their last fire.
Without this fire regime areas went unburnt for years, leaving a massive amount of combustible material in the system. When lightning strikes and ignites it the fires are huge, killing all the big trees and burning most things in its path. By regularly burning areas the fuel can’t build up and the fires are less intense. And it creates breaks at which lightning struck fires, which would otherwise become massive, stop in their tracks.
AWC are working with various agencies including CSIRO (Australia’s national science agency) to determine the effect of a return to more traditional fire regimes, both on the wildlife and, intriguingly, on the whole climate. This could be a massive deal. If burning regularly, early in the dry season decreases the total amount of fuel burnt (compared to the high intensity fires caused later in the season by lightning), then these “ecofires” could reduce the amount of carbon being released.
The wildlife trapping surveys are just part of it – to see how the animals and plants are affected by the fires. Other work is being done to calculate exactly how much carbon and other greenhouse gases are being emitted by each kind of fire. The matter is coming up before parliament: the carbon saved by early low intensity fires could be used for emissions trading schemes – a revenue source that is of interest to more than just conservationists.