Research Potential at Kachana Pastoral Station
By Anna Price
The kimberly covers an area of 423000 km 2 and half of this area is pastoral lease. Kachana is a unique Pastoral lease due to the method of land use practiced by Chris Hengler. The emphasis at Kachana is on sustainable management of the land, rather than on production of meat at the expense of a healthy landscape. The animals at Kachana are used to manage the land rather than the land used to manage animals, with the primary goal being resource stabilisation. Stabilisation of the land involves elimination of pressures caused by regular burning and free ranging cattle grazing that results in loss of productivity mainly through erosion. The desired outcome of this type of land management is to create a healthy ecosystem measured through biomass and biodiversity.
Figure 1: Satellite imaging of increasing fire scars in the Kimberly between 1993 and 1995.
As a result of the sustainable management of Kachana opportunities for research are prevalent. But this research can be directed along two different paths. The diversity of ecosystems in close proximity to each other affords the opportunity for a wide range of comparative studies. This lends itself to genetic studies as well as ecological process studies. The other path of research is obviously related to the effectiveness of animals as a land management tool in comparison to other methods, particularly fire.
Before any of these studies can be conducted the current state of the environment should be established. This would include water quality analysis and faunal presence and diversity studies. With greatest ease these surveys can be performed on fish (netting and electrofishing), reptiles (pit traps and elliot traps), frogs (observation), birds (observation) and flora (observation). For birds and fish preliminary lists have been compiled by Steve McIntosh. To create comprehensive species list would not be too strenuous, the greatest challenge would be equipment transport between locations, easily overcome with use of a pack horse or donkey.
Using these basic studies any differences in composition between ecosystems can be established. For freshwater ecosystems this would probably be most evident between Rock Wallaby Gorge, Cleanskin Gorge and Lee Creek Gorge, as upper catchment aquatic ecosystems. They are located within a few kilometers of each other and are widely different. Rock Wallaby Gorge is very narrow with a large quantity of organic matter in the pools and what appears to be coloured (tannined) water. Cleanskin Gorge is much wider and less shaded, the pools are deeper and the water is more green, suggesting phytoplankton activity rather than high organic carbon content. Lee Creek Gorge is different again, much smaller and it would appear a different rock type forms the substrate of this stream. The rocks are much whiter than the other gorges. It would be interesting to determine the effects, if any, these physical differences would have on aquatic fauna.
For terrestrial ecosystems variations would probably be most evident under different land use practices. These would include;
Once the baseline studies have been completed the impacts of a catastrophic effect, such as fire (ie, one intense fire over long period versus less intense more regular fires), invasion by cane toads or tourism can be monitored. More sensitive ecosystems will most probably exhibit greater impacts and will take a longer time to recover and the successional changes during recovery will probably vary with how robust the ecosystem is.
With these baseline studies a desktop comparison with other surveys in the Kimberly can be undertaken and in turn any uniqueness in Kachana be deciphered (References of other Kimberly research below). If any fauna is discovered as being unique to Kachana further research funds would probably be available to determine its habitat and classify it.
Further research particular to Kachana includes the impacts of largely unrestricted cattle access on river health when intensively managed. Chris does not fence off the river systems when grazing his cattle around them. This appears to encourage invasion of the banks and water with large quantities of cooch grass. This may provide habitat and refugia for aquatic fauna or may shade the river and de-oxygenate the water overnight to such an extent that it is inhabitable and fauna move away from these areas. Inverstigation this and the recovery of the river to this kind of impact may assist in understanding aquatic response to intensive impacts.
The advantage of managing cattle as Chris does is that the improved productivity of the soil means greater plant growth and hence greater soil stabilization. A simple study to determine the effectiveness of this on erosion would be to take water samples throughout the year above Chris’ managed area and below to see if there is any change in turbidity of the water.
Sediment from unmanaged land = TSS 3-TSS 2
Sediment from managed land = TSS 2-TSS 1
Where TSS is Total Suspended Solids
In addition, by analyzing the nutrient content in the water, it would be possible to determine how many nutrients are being injected into the river systems from the large concentration of cattle in close proximity to the river. The water sampling could be timed to coincide with flights into town so that they can then be transported to Perth for analysis.
Kachana offers an ideal research opportunity over other locations due to the variety of ecosystems in close proximity and the different land uses being practiced.
Examples of Previous Kimberly Research
McCarthy G. (1993) Kimberley Bird List. Geology Naturalist 30(2) 36-41.
Coate K.H., Johnstone R.E. & Lodge G.A. (2001) Birds of Kingston Rest north-east Kimberley, Western Australia. Western Australian Naturalist 23(1) 9-38.
Coate K.H., Johnstone R.E. & Lodge G.A. (1998) Birds of the Gardner and Denison ranges, and Lake Willson area south-east Kimberley, Western Australia. Western Australian Naturalist 22(1) 25-53.
Chapman A., Harold G. & Milewski T. (1993) Birds of the Munja-Walcott Inlet area. West Kimberly, Western Australia. Western Australian Naturalist 19(2) 147-161.
Aumann, T. (1991) Notes on the birds of the upper and middle reaches of the Kimberley rivers during the dry season. Australian Bird Watcher 14(2) 51-67.
Horstman M. (2001) Collaborative surveys of fish in the Fitzroy River, Western Australia. Ecological Management and Restoration 2(3) 235-236.
Tyler M.J., Smith L.A. & Johnstone R.E. (1994) Frogs of Western Australia. Western Australian Museum, Perth, 1-187.
Chapman A. (1993) Mammals of the Munja-Walcott Inlet area. West Kimberly, Western Australia. Western Australian Naturalist 19(2) 140-146.
McKenzie, N.L., Johnston R.B. & Kendrick P.G. (1991) Kimberly rainforests of Australia . Surrey Beatty & Sons, Chipping Norton, N.S.W., Australia. 1-490.
Tyler M.J., Davies M. & Watson G.F. (1987) Frogs of the Gibb River Road, Kimberley Division, Western Australia. Records of the Western Australian Museum 13(4) 541-552.