- Impacts of exclusion fencing on target and non-target fauna: a global review
- Expansion of Vertebrate Pest Exclusion Fencing and its Potential Benefits for Threatened Fauna Recovery in Australia
- A physiological assessment of the use of water point closures to control kangaroo numbers
- An electrified watering trough that selectively excludes kangaroos
- Do kangaroos exhibit water-focused grazing patterns in arid New South Wales? A case study in Sturt National Park
- Fencing artificial waterpoints failed to influence density and distribution of red kangaroos (Macropus rufus)
- Going the distance on kangaroos and water: A review and test of artificial water point closures in Australia
- Artificial watering points are focal points for activity by an invasive herbivore but not native herbivores in conservation reserves in arid Australia
- Management of Artificial Water Points on National Parks in Western Queensland
- The efficacy of Finlayson troughs as a means of repelling kangaroos from water and altering grazing pressure in pastoral areas
- Ecological connectivity or Barrier Fence? Critical choices on the agricultural margins of Western Australia
- Use of the Finlayson trough as an aid to kangaroo harvesting
- Fences or Ferals? Benefits and Costs of Conservation Fencing in Australia
- Fencing for conservation: Restriction of evolutionary potential or a riposte to threatening processes?
(Smith, King, & Allen, 2020)
Exclusion fencing is a common tool used to mitigate a variety of unwanted economic losses caused by problematic wildlife. While the potential for agricultural, ecological and economic benefits of pest animal exclusion are often apparent, what is less clear are the costs and benefits to sympatric non‐target wildlife. This review examines the use of exclusion fencing in a variety of situations around the world to elucidate the potential outcomes of such fencing for wildlife and apply this knowledge to the recent uptake of exclusion fencing on livestock properties in the Australian rangelands.
Expansion of Vertebrate Pest Exclusion Fencing and its Potential Benefits for Threatened Fauna Recovery in Australia
(Smith, Waddell, & Allen, 2020)
Globally, there is a need to preserve threatened species before they disappear. The management of these species is often aided, particularly in Australia, by the addition of exclusion fences that prevent the movement of invasive or pest predators and competitors into the conservation area. Widespread use of conservation fences is limited by the availability of suitable conservation land and the relatively high costs of such fencing. Here, we discuss the potential conservation benefit of pest exclusion fences erected on agricultural land. We assess the spatial overlap of existing agricultural exclusion fences (known as “cluster fences”) with the potential habitat of listed threatened species and consider whether or not identified threats to these species are potentially alleviated within cluster fences. We find that there are several species that face threats which may be alleviated with cluster fences and propose that active recovery of threatened species on fenced agricultural land be seriously considered.
Remote sensing of trophic cascades: multi-temporal landsat imagery reveals vegetation change driven by the removal of an apex predator
(Fisher et al, 2021)
Trophic cascade theory predicts that predators indirectly benefit plants by limiting herbivore consumption. As humans have removed large predators from most terrestrial ecosystems the effect of their absence is unrecognized. A manipulation of dingo populations across Australia’s dingo-proof fence, within the Strzelecki Desert, was used to assess how predator absence has altered vegetation cover dynamics at landscape and site scales.
Landscape-scale analysis used Landsat fractional vegetation cover time series statistics to classify landforms and examine vegetation dynamics either side of the dingo fence. Generalised additive models were used to analyse the influence of predator absence on site-scale observations of fauna abundance and vegetation cover. The location of the dingo fence was visible as a change in both the standard deviation and maximum of non-photosynthetic vegetation (NPV) cover (e.g. wood and dry leaves) over 32 years (1988–2020). On average, NPV cover of swales decreased in the standard deviation by 1.4% and in the maximum by 5.0% where dingo abundance was reduced. The differences were consistent with suppressed vegetation growth following rainfall, due to high grazing pressure, where predators were rare. The landscape-scale analysis was supported by site-scale observations. The influence of the trophic cascade was observable at both the landscape and site scales, suggesting that apex predator removal has significantly affected the arid ecosystem’s responses to resource pulses. Analogous effects may exist across the large areas of the planet over which apex predators have been extirpated.
(Underhill, Grigg, GC, Pople, AR, & Yates, DJ, 2007)
Controlling kangaroo grazing pressure in national parks without harvesting or culling presents a significant challenge. Fencing off waterpoints is often tried or contemplated as a control measure, but its success obviously depends upon the extent to which kangaroos require access to discrete sources of drinking water. To assess the necessity for red kangaroos to supplement dietary water intake under different conditions by drinking free water, this study followed changes in diet and in forage water and energy content as severe drought deepened at Idalia National Park in central Queensland from February to July 2002, the driest of 13 years for which records exist. Animals smaller than 15 kg in February and 25 kg in April did not need free water, but larger individuals needed to drink throughout the period. By July all animals needed to drink. The influence of body size arose because water requirements scale almost proportionally with body mass (M0.92) while energy requirements scale with a lower exponent (M0.74). Because of the sexual dimorphism in red kangaroos, adult females are therefore better able than adult males to survive water shortage. The results help define the constraints that physiological capabilities confer upon the usefulness of fencing off water points to control kangaroos. Smaller (younger) males and females could tolerate dry, cool conditions without drinking, even in this very dry year, but kangaroos of allbody sizes needed to drink as the drought became more severe. The effectiveness of water closure therefore depends on what forage is available, will target larger animals selectively, and will be most effective in semiarid areas like Idalia National Park in very dry years and late in the dry season when temperatures are rising and water requirements increase because of additional requirements for thermoregulation.
Norbury, G L (1992)
It is generally agreed that the provision of artificial watering points has allowed populations of large kangaroos to increase in the arid and semi-arid rangelands. This study examines the effectiveness of a selective watering device, known as a “Finlayson Trough”, which is designed to exclude kangaroos but allow sheep to drink. The device is a low-lying electrified wire that surrounds a trough and is overstepped by sheep but contacted by a kangaroo’s feet or tail. Of the 292 observed attempts at drinking by red kangaroos (Macropus rufus), 99% were unsuccessful. Of the 309 observed attempts by sheep there were minor shocks to the legs in 17% of cases which resulted in only short-term disruptions to drinking. Norbury concludes that these troughs, combined with a grazing management strategy that embraces all herbivores, could provide a significant tool for managing access to water in the arid and semi-arid rangelands.
Do kangaroos exhibit water-focused grazing patterns in arid New South Wales? A case study in Sturt National Park
(Montague-Drake & Croft, D B, 2004)
The density of kangaroos within 5km of current and former artificial water points in Sturt National Park was studied over a two-year period using the line transect method. Kangaroo densities were not significantly related to water proximity and did not significantly differ between open and closed watering points. Infrared sensors detected and counted kangaroo movements to and from artificial watering points and these were positively correlated with temperature. However, line transect counts did not reveal a shift in kangaroo distributions to water-proximate areas in warmer seasons. The results suggest that kangaroos travel to drink and then return to relatively stable home ranges that take advantage of sites offering the best grazing and resting opportunities. Vegetation surveys, using a wheel point device, revealed that the biomass of Atriplex spp. decreased significantly with increased proximity to artificial watering points, but the biomass of Poaceae spp. and numerous forbs did not. Vegetative diversity was unrelated to water proximity. Low vegetation biomass near artificial watering points in Sturt National Park may be more correctly attributed to the effects from past sheep-grazing pressure, than to any current grazing pressure. The researchers concluded that kangaroos were not exhibiting water-focused grazing patterns at that time and were evenly distributed throughout the landscape. Whilst small-scale closure may not alter kangaroo grazing pressure, the impacts of large-scale watering point closure is still uncertain.
Fencing artificial waterpoints failed to influence density and distribution of red kangaroos (Macropus rufus)
(Fukuda, McCallum, H I, Grigg, G C, & Pople, A R, 2009)
Provision of artificial waterpoints in Australian rangelands has resulted in an increase in the range and density of kangaroos. At high densities, kangaroos can inhibit vegetation regeneration, particularly in some protected areas where harvesting is prohibited. Fencing off waterpoints has been proposed to limit these impacts. The aim of this study was to determine whether fencing off waterpoints during a drought (when kangaroos would be especially water-limited) would influence the density and distribution of red kangaroos (Macropus rufus). Two waterpoints were fenced within the first 6 months of the 27-month study and a furthertwo waterpoints were kept unfenced as controls in Idalia National Park, western Queensland. Kangaroo densities around waterpoints were estimated from walked line-transect counts, and their grazing distribution from dung-pellet counts. Fencing off waterpoints failed to influence either the density or distribution up to 4 km from the waterpoints. The results indicated that food availability, rather than the location of waterpoints, determines kangaroo distribution. Few areas in the rangelands are beyond kangaroos’ convenient reach from permanent waterpoints. Therefore, fencing off waterpoints without explicitly considering the spatial context in relation to other available water sources will fail to achieve vegetationregeneration.
Going the distance on kangaroos and water: A review and test of artificial water point closures in Australia
(Lavery, Pople, Anthony R, & McCallum, Hamish I, 2018)
This study reviewed water-point closures in Australia and found experimental tests have been few and results unconvincing for two main reasons. Firstly, no study has tested AWP closures over distances influential to kangaroos. Secondly, post-closure monitoring has frequently been too short to detect changes mongst natural environmental fluctuations. Their own experimental AWP closure did not influence kangaroo populations and reaffirmed for the researchers that kangaroo densities are dictated by food availability in Australia’s water rich rangelands. They concluded that larger experiments are needed with systematic AWP closures that generate water remote landscapes, preferably exceeding 10 km from water and that monitoring must span dry, hot periods of below average rainfall when kangaroos are most likely to be dependent on drinking water.
Artificial watering points are focal points for activity by an invasive herbivore but not native herbivores in conservation reserves in arid Australia
(Letnic, Mike, et al., 2014)
In this study, they used dung count indices to investigate the activity of an invasive herbivore, feral goats (Capra hircus), and native herbivores (kangaroos, Macropus spp.) in relation to surface water and habitat type in three conservation reserves located in arid Australia. Activity of feral goats showed a strong preference for rocky ranges habitat and decreased with distance from water. Kangaroo activity showed a strong preference for mulga woodlands, but was independent of distance from water. Results suggested that artiﬁcial water points may exacerbate the impacts of feral goats by functioning as focal points for their activity. Restricting goats’ access to water by closure of water points or strategic fencing, such that the mean distance to water across the landscape is increased, may be an effective strategy to reduce goat grazing impacts in conservation reserves where natural sources of water are scarce but is unlikely to affect the grazing patterns of kangaroos. This study suggests that there is scope to control populations of water-dependent invasive vertebrates in arid regions by restricting their access to artiﬁcial water points.
Management of Artificial Water Points on National Parks in Western Queensland
(Pople & Page, Manda, 2002)
This report built on previous research into AWP management and the objective was to identify specific concerns for National Parks in Western Queensland, particularly Idalia NP and Currawinya NP, and whether water point closure was appropriate. The report reviews the literature on the ecological impacts of AWP’s in arid and semi-arid Australia and uses that information to assess the value of closing AWP’s in the parks mentioned. The report also presents a possible strategy and suggests appropriate monitoring for the actions.
The efficacy of Finlayson troughs as a means of repelling kangaroos from water and altering grazing pressure in pastoral areas
(King, Norbury, G L, & Eliot, G J, 1996)
In 1993 all water sources within a 100,000 ha area had either activated Finlayson troughs or were fenced off. This research involved using aerial surveys and radio-tracking to determine the numbers and distribution of kangaroos over the whole area and found there were no significant differences in kangaroo numbers between the treated area and a nearby control area. All 31 of the radio-collared kangaroos which could be located at the end of the trial remained within the areas they formerly occupied and the length of their movements did not increase. It was discovered that kangaroos found methods that enabled them to circumvent the Finlayson troughs within two weeks of activation and the researchers deemed them ineffective in terms of restricting access of kangaroos to water.
Ecological connectivity or Barrier Fence? Critical choices on the agricultural margins of Western Australia
(Bradby, Fitzsimons, Del Marco, & Driscoll, 2014)
Western Australia’s State Barrier Fence represents a continuation of colonial era attitudes that considered kangaroos, emus and dingoes as ‘vermin’. Recent plans to upgrade and extend the Barrier Fence have shown little regard for ecological impacts or statutory environmental assessment processes.
Use of the Finlayson trough as an aid to kangaroo harvesting
(Hacker & Freudenberger, D, 2012)
Previously reported observations indicate that concentrations of kangaroos can occur around activated Finlayson troughs during hot weather but not when conditions are mild. This paper investigated whether this could make the device effective as an aid for kangaroo harvesting. The conclusion was that the Finlayson trough could substantially improve the efficiency of kangaroo harvesting under ideal (hot,dry) conditions but that successful application would be opportunistic rather than routine.
(Dickman C. R., 2012)
One of the most intractable problems for the conservation of many species of native Australian vertebrates is predation from the introduced red fox Vulpes vulpes and feral house cat Felis catus. In recent years, increasing use has been made of conservation fences that exclude these introduced species and provide protection for large and viable populations of high-value native species within the fenced areas.
Fencing for conservation: Restriction of evolutionary potential or a riposte to threatening processes?
(Hayward & Kerley, 2009)
Fencing for conservation is an acknowledgement that we are failing to successfully coexist with and, ultimately, conserve biodiversity. Fences arose during the Neolithic revolution to demarcate resource-rich areas (food sources) and exclude threats (intruders). Fencing for conservation can be viewed as fulfilling a similar function. The aims of this paper were to identify when fencing can and is used to conserve biodiversity; highlight the costs and benefits of fencing for conservation; and make recommendations to ensure appropriate use of fencing for conservation in the future. The IUCN identifies ten major threatening processes and the impacts of eight of these can be mitigated via the use of fencing, however avoiding human–animal conflict and reducing the impact of introduced predators are the two most common uses. Fences implemented to achieve a conservation benefit are not necessarily physical barriers, but can also include ‘metaphorical’ fences of sound, smoke and smell, or even actual islands. Fences provide defined units for managers and separate biodiversity from threatening processes including human persecution, invasive species and disease. Conversely, they are costly to build and maintain; they have ecological costs through blocking migration routes, restriction of biodiversity range use which may result in overabundance, inbreeding and isolation; restriction of evolutionary potential; management; amenity and ethical costs. Despite these problems, fencing for conservation is likely to become increasingly utilized as biodiversity becomes increasingly threatened and methods of ameliorating threats lag behind. In the long-term, fences may ultimately prove to be as much a threat to biodiversity as the threats they are meant to exclude, and a new research agenda should arise to ensure that conservation fences do not remain a permanent part of the landscape.