Exploiting drought opportunities: control of total grazing pressure of grasslands
Hacker, R. Dr.: Ph. (02) 6888 7404; ron.hacker@agric.nsw.gov.au
Research organisation: NSW Agriculture
Collaborator: CSIRO Wildlife and Ecology
Sponsors: LWRRDC, Land and Water Resources Research and Development Corporation; International Wool Secretariat
Note that this project has been combined with the project 'Tactical management of total grazing pressure in rangelands by manipulating access to water supplies', funded by the International Wool Secretariat.
Objectives:
1. To evaluate the potential for tactical rangeland management by manipulating access to water of kangaroos and feral goats:
(a) To evaluate the extent to which exclusion of kangaroos from watering points facilitates commercial harvesting.
(b) To conduct a preliminary evaluation of the potential of feed attractants as a means of concentrating kangaroos for commercial or non-commercial culling.
2. To develop guidelines for application of techniques to control grazing by kangaroos and feral goats.
Methodology:
Low lying electric wires around artificial stock watering points were evaluated as a means of excluding kangaroos from water, while allowing access by domestic stock. The effects of both short and long term installations were evaluated. Preliminary evaluation of feed attractants as a means of concentrating kangaroos utilised both lucerne hay and irrigated pasture. Trap yards on watering points were evaluated as a means of reducing feral goat populations.
Progress:
The project resulted in the following conclusions:
Low lying electrified wires surrounding watering points are largely, though not universally, effective in excluding kangaroos from water. Grey kangaroos (Macropus giganteus and M. fuliginous) attempt to cross the electrified wires more persistently than reds (M. rufus), but most kangaroos are unable to drink normally in the presence of the barrier. Some livestock will experience shocks when exposed to the wire, but no unmanageable effects were observed. A modified design will be required for waters used by cattle to avoid damage to the conventional installation.
Finlayson troughs are sufficiently effective in excluding kangaroos from water to stimulate significant concentrations of animals in their immediate vicinity under hot and dry conditions. Under mild conditions no such concentration occurs, regardless of the moisture content of forage, primarily because of the reduced numbers of animals converging on water at any time. The response under high temperature conditions in the presence of green feed has not been defined. Kangaroo activity at water points is variable depending on time of day, weather conditions and preferences for individual waters.
Finlayson troughs can substantially improve the efficiency of kangaroo harvesting under ideal (hot, dry) conditions when substantial concentrations of animals occur in the vicinity of protected waters.
No marked tendency for kangaroos to concentrate on feed attractants in a way that would facilitate harvesting was demonstrated, but the preliminary nature of these observations requires cautious interpretation.
Kangaroo and feral goat grazing pressure was not markedly reduced by closure of waters over 'paddock-sized' areas for up to 10 weeks during relatively mild summer conditions. Establishment of Finlayson trough networks cannot be justified by our results. However, there is sufficient evidence to suggest that closure of internal watering points should occur whenever a paddock is destocked for shearing or some other purpose. This may reduce the tendency for kangaroos, particularly reds, to graze preferentially in these paddocks.
Weather conditions prevented a thorough evaluation of the effectiveness of individual traps for feral goat control. However, we concluded that such facilities are unlikely to be effective in reducing local goat populations except perhaps in specific circumstances (eg. on isolated waters under hot, dry conditions).
There is widespread awareness among graziers in the Western Division of the Finlayson Trough, or similar water exclusion techniques. However, few graziers have attempted to utilise the device either as an aid to commercial kangaroo harvesting or as a means of protecting destocked areas.
Period: starting date 1994-01; completion date 1996-06
Status: completed
Keywords: Kangaroos, feral goats, total grazing pressure, water supplies
Publications:
Freudenberger, D. and Hacker, R. (1995). The short-term effect of selectively excluding kangaroos from stock watering points. Proceedings of the 10th Australian Vertebrate Pest Control Conference, Hobart, Tasmania, pp 309-312.
Freudenberger, D.O. and Hacker, R.B. (1997). The effect of temporary closure of watering points on grazing intensity of red and grey kangaroos with related observations on feral goats. The Rangeland Journal 19, 157-165.
Freudenberger, D.O., Hacker, R.B. and Brill, B. (1995). Management of total grazing pressure in rangelands by manipulating access to water supplies. In M.J. Page and T.S. Beutel (eds.) Proceedings of Conference on the Ecological Research and Management in the Mulgalands, University of Queensland Gatton College, Australia, pp. 133-138.
Freudenberger, D., Hacker, R. and Palmer, R. (1997). Temporary closure of watering points is an opportunistic tool for reducing kangaroo and feral goat grazing pressure. 9th Annual Meeting of the Australasian Wildlife Management Society, Canberra.
Hacker, R. (1996). Managing grazing pressure in rangelands. Proceedings of Managing with Climate Variability Conference 'Of droughts and flooding rains', 6-17 November 1995. LWRRDC Occasional Paper CV03/95, pp. 79-84.
Hacker, R.B. and Freudenberger, D. (1996). Use of the Finlayson trough as an aid to kangaroo harvesting. In L.P. Hunt and R Sinclair (eds.) Focus on the Future - the Heat is On! Conference Papers, 9th Biennial Conference, Australian Rangeland Society. pp 173-4.
Hacker, R.B. and Freudenberger, D.O. (1997). The effect of short-term exclosure of watering points on the behaviour and harvesting efficiency of grey and red kangaroos. The Rangeland Journal 19, 145-156.
Hacker R.B. and Freudenberger, D. and Brill, B.J. (1996). Control of total grazing pressure in rangelands by manipulating access to water supplies. Final report to International Wool Secretariat and Land and Water Resources R&D Corporation. Project DAN210.
