Feral horse damage to a small stream (Photo: Nick Clemann)
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The ecological, ethical and economic evidence for removing feral horses from Australia’s alpine environments

Thursday, 2 July 2020  | 

Feral horses (Equus caballus) are hard-hooved, introduced herbivores originating primarily from farms but now occurring across mainland Australia. Damage by horses is recognised as a threatening process in NSW and Victoria due to its impact on native species and ecosystems.

Feral horse impacts are best understood in Australia’s alpine ecosystems where there are ~25,000 horses, increasing at ~20% per year. They cause environmental degradation, even at low numbers. They overgraze endangered plant communities, affect alpine plant and animal abundance and diversity; spread invasive plants; erode soil; and increase sediment in waterways.

Feral horse trampling reduces the organic layer of soils, increases soil compaction and run-off, and reduces water infiltration and nutrient recycling. Frequent visits to water sources create compacted paths that damage vegetation and reduces streambank stability. Horse paths create channels that drain peatland communities, causing peatlands to dry, degrade, and release carbon into the atmosphere.

By degrading ecological communities, horse activity may increase the extinction risk of threatened species, including Alpine Water Skinks, Northern Corroboree Frogs, Mountain Pygmy Possums, Stocky Galaxias, Guthega Skinks, and 23 plant species in NSW. Feral horses can eliminate Broad-toothed Rat populations when impacts are severe, and when combined with deer, can halve invertebrate numbers. Experimental exclusion of feral horses increases the soil organic layer leaf litter and reduces erosion, and exclusion of horses and deer increases native vegetation richness, cover, and biomass, and reduces weeds.

Management of feral horses is necessary to address negative ecological impacts. Aerial culling is the most cost-effective and humane method for managing feral horses. Mustering and rehoming is more expensive and delivers poorer horse welfare outcomes. Fertility control is ineffective because the populations are too large, are often in regions very difficult to access, and are open to immigration.

The evidence shows that maintaining feral horse populations is inconsistent with biodiversity conservation.

Research Entries

Title
Aims
Results
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Beeton, N. J., & Johnson, C. N. (2019). Modelling horse management in the Australian Alps. Ecological management & restoration, 20(1), 57-62.
Used a spatially explicit population model to compare the potential effects of two different management strategies on populations of horses in the Australian Alps bioregion: culling from helicopters versus trapping and mustering
1. Mustering is always less cost-effective and more expensive per animal than aerial culling2. Aerial culling always produces the best outcomes in terms of reducing final population numbers and cost-effectiveness of management. In all simulation scenarios, ‘no management’ results in the highest final population of feral horses, followed by trapping and mustering, then aerial culling in Victoria, then VIC & NSW aerial culling with the lowest final populations of feral horses.
Cairns, S. (2019). Feral Horses in the Australian Alps: the Analysis of Aerial Surveys Conducted in April-May, 2014 and April-May 2019.
To conduct a repeat aerial survey of feral horses to evaluate change over time since 2014
1. The number of horses in the North Kosciusko block increased significantly from 3,255 in 2014 to 15,687 in 2019. Overall annual finite rate of population increase was 1.370, or 37%.2. Across all survey sites (North Kosciusko, Byado-Victoria and Bago-Maragle blocks, 2860 km2), the total number of feral horses was 9,187 in 2014 and 25,318 in 2019. Overall annual finite rate of population increase was 1.225, or 23%.2. Feral horse density to between 6.84 and 13.88 horses km?2 (average 10.13) in North Kosciusko grasslands and open woodlands, and between 0.98 and 3.31 horses km?2 in medium terrain woodlands across all study blocks. Feral horse population in the North Kosciuszko block has a doubling time of 2.20 years.
Cherubin, R. C., Venn, S. E., Driscoll, D. A., Doherty, T. S., & Ritchie, E. G. (2019). Feral horse impacts on threatened plants and animals in sub?alpine and montane environments in Victoria, Australia. Ecological management & restoration, 20(1), 47-56.
To quantify the effects of feral horses on Sphagnum bogcommunities and two associated threatenedanimal species (Alpine water skink and broad-toothed rat).
Feral horses associated with vegetation types and characteristics that negatively influence the presence or abundanceof Alpine Water Skink and Broad-toothed Rat. Sites with high horse activity had more low-growing forbs, and the abundance of Alpine Water Skink was negatively related to this vegetation type. Grasses, sedges, rushes and shrubs were also less dense and lower in height in high horse activity sites, and Broad-toothed Rat was less likely to be present in areas with these habitat attributes.'
de Bie K. and Vesk P. A. (2014) Ecological indicators for assessing management effectiveness: a case study of horse riding in an Alpine National Park. Ecological Management and Restoration 15, 215–221.
To determine the efficacy of ecological indicators as performance measures in assessing the effectiveness of a management strategy implemented to minimize the impact of horse riding on a valuable and sensitive alpine vegetation community in a National Park.'
There were significant differences in the amount of bare ground, the height of shrubs and ground layer vegetation, and shrub cover between track and control plots in 2001. Ten years later, track plots were recovering with reductions in bare ground and changes in vegetation, with improved ground layer vegetation height. Results show that vegetation condition has improved with restrictions of horse numbers.'
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Eldridge, D. J., Ding, J., & Travers, S. K. (2020). Feral horse activity reduces environmental quality in ecosystems globally. Biological Conservation, 241, 108367.
Combined a structured, qualitative search of global literature with a quantitative meta-analysis to explore the net effects of feral horses on ecosystems worldwide. Retrieved 4261 observations from 78 publications that reported quantitative data on the effects of feral horses on 64 ecosystem response variables such as plant community composition and cover; soil chemistry and soil stability, that together give us a measure of environmental quality.
Across all countries around the globe that have researched feral horse impacts:1. Feral horse activity leads to substantial, non-trivial reductions in ecosystem functions and biomass - on average, 19% reduction in ecosystem function, 31% decline in litter levels, 25% decline in plant biomass, highly variable declines in composition (5%) and structure (8%). Reductions in plant biomass, height and structure resulting from increasing horse activity could lead to a number of potential outcomes such as: 1) alteration to plant cover, richness and composition (Lopez et al., 2017); 2) reduced vegetation structure and therefore habitat quality, which has been shown to alter ant community composition, 3) reduced capacity for production of litter and organic matter, and thus increased soil erosion risk, and 4) reduced organic matter inputs into thesoil, with feedback effects on soil biota, microbially-mediated decomposition and therefore soil nutrient pools.2. Feral horse activity increases erosion risk - on average, 31% increase in soil erosion. Feral horses increased erosion by pugging and streambed widening in riparian areas. Impacts highly variable and vary with factors such as vegetation type, density, soil properties, slope and level of utilisation.Posssible positive effects of low grazing activity (as found elsewhere for cattle and African systems where ungulates have co-evolved with ecosystems) are unlikely in continents that lack native hard-hoofed ungulates such as Australia.
Eldridge, D. J., Travers, S. K., Val, J., Zaja, A., & Veblen, K. E. (2019). Horse activity is associated with degraded subalpine grassland structure and reduced habitat for a threatened rodent. Rangeland ecology & management, 72(3), 467-473.
To examine the the direct and indirect impacts of horses, kangaroos, and rabbits on the threatened broad-toothed rat (Mastacomys fuscus), by investigating the relationship between the activity of different herbivores and 1) structural attributes of the vegetation (cover and density of different plant groups) and 2) length of broad-toothed rat runways and the presence of scat along these runways as proxies of broad-toothed rat activity.
1. Quadrats showing no evidence of horse activity had longer broad-toothed rat runways, taller but fewer grasses, double the shrub cover, and lower plant richness than quadrats showing evidence of horse activity.2. Structural equation modelling showed no significant direct associations between horse activity and rat activity.3. Horses have an indirect negative effect on broad-toothed rat habitat by reducing grass height and altering plant species richness. 4. Other herbivores (rabbits, kangaroos) are not responsible for differences in broad-toothed rats across grazed and ungrazed habitats. There were no significant effects of rabbits on any environmental variables, and kangaroo grazing was associated with an increase in shrub cover only.
Foster, C. N., & Scheele, B. C. (2019). Feral-horse impacts on corroboree frog habitat in the Australian Alps. Wildlife Research, 46(2), 184-190.
Used replicated horse exclosures to investigate the effects of feral horses on breeding habitat of the critically endangered northern corroboree frog, Pseudophryne pengilleyi
1. Depth of leaf litter in wetlands significantly affected by the presence of feral horses.2. Pool-edge litter 1.9 times deeper in areas without horses (inside horse-exclosure plots and horse-free sites) than in areas accessible to horses (unfenced areas in horse-occupied sites).
Good, R., & Johnston, S. (2019). Rehabilitation and revegetation of the Kosciuszko summit area, following the removal of grazing–An historic review. Ecological management & restoration, 20(1), 13-20.
Historical account of the rehabilitation and revegetation of the Kosciuszkosummit following the cessation of grazing
...the landscape was once degraded and severely eroded, devoid of many of the natural catch-ment values so important to the discharge of water to the rivers and to the Snowy MountainsHydro-electric Scheme. The rehabilitation of the alpine zone has contributed to and seen therecovery of many native species and communities, some nearing extinction during the graz-ing years, such that their conservation will be forever ensured.'
Hobbs R. J. and Hinds L. A. (2018) Could current fertility control methods be effective for landscape?scale management of populations of wild horses (Equus caballus) in Australia? Wildlife Research 45, 195–207.
to evaluate currently available non-lethal fertility-control methods that have been tested for their contraceptive efficacy in Equidae, and to assess their suitability for effective management of wild (feral) horses in an Australian setting.'
Throughout Australia, populations of wild horses are dispersed over large areas, in varied and difficult-to-access terrain and vegetation. Moreover, horse herds are open to immigration and introductions from neighbouring populations, making them poor choices for the successful application of currently available fertility-control agents. Applied alone, fertility control will not reduce horse numbers within 10 years and will not effectively halt population growth unless enough mares within those populations are treated concurrently and every 2–4 years in relation to the contraceptive used and to the duration of infertilityinduced by the specific contraceptives.'
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Nimmo, D.G., & Miller, K.K. (2007) Ecological and human dimensions of management of feral horses in Australia: a review. Wildlife Research 34(5) 408–417
To review evidence of the ecological impacts of feral horses on non-native ecosystems, with a focus on Australian ecosystems
The review found that documented environmental effects of feral horses include: •soil loss, compaction and erosion •trampling of vegetation •reducing plant species richness •inducing mortality of native trees through bark chewing •damage to bog habitat •damage to water bodies •facilitation of weed invasion •altering community composition of birds, fish, crabs, small mammals, reptiles and ants.
Porfirio, L. L., Lefroy, T., Hugh, S., & Mackey, B. (2017). Monitoring the impact of feral horses on vegetation condition using remotely sensed fPAR: A case study in Australia's Alpine Parks. Parks, 27.
To compare field and remotely-sensed satellite assessments of vegetation condition in sites where feral horses were present and absent, in conjunction with field-based observations of horse presence and absence.
1. Presence of feral horses is correlated with reduced condition of natural treeless drainage systems (riparian areas and wetlands) in the Australian Alps2. Significant differences in field-monitored Landscape Function Analysis (LFA- uses indicators to assess the status of biotic and abiotic processes that retain water and nutrients) index between sites where horses were present or absent. Vegetation condition was lower in sites with feral horses.3. Significant differences in remotely-sensed fraction of photosynthetic active radiation (fPAR - a measure of vegetation cover and productivity) between sites where horses were present or absent. Sites with presence of horses have 10% lower fPAR than sites with absence of horses.4. Significant correlation between field-based and remotely-sensed condition assessments
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Robertson, G., Wright, J., Brown, D., Yuen, K. and Tongway, D. (2019), An assessment of feral horse impacts on treeless drainage lines in the Australian Alps. Ecol Manag Restor, 20: 21-30. doi:10.1111/emr.12359
Compares indicators of soil and streambank stability and vegetation cover of treeless drainage lines in sites with no sign of horse presence and sites that do show evidence of horse presence (observations of horses, horse dung, hoof prints or trails).
1. Significant differences among horse-occupied and horse-free sites for all nine indicators of soil and stream stability assessed. 2. For all soil and stream stability indicators assessed (including nutrient pollution, streambank stability, stream depth, siltation, and pugging), the average score and environmental condition was worse in horse-occupied areas. Sites in poorest condition were occupied by horses. 3. No significant differences among horse-occupied and horse-free sites in projected foliage cover.4. Horses predominant cause of differences between sites - other mammalian herbivores species (wombats, macropods, and feral goats, rabbits, pigs and deer) had only minor mpacts on alpine ecosystems.
Schulz, M., Schroder, M., & Green, K. (2019). The occurrence of the Broad?toothed Rat Mastacomys fuscus in relation to feral Horse impacts. Ecological management & restoration, 20(1), 31-36.
Surveyed 180 sites supporting preferred habitat for the nationally threatened Broad-toothed Rat (Mastacomys fuscus) to determine presence and relative abundance in relation to the level of feral horse impacts
1. Significant negative relationship between feral horse impacts and both Broad-toothed Rat presence and abundance2. No rat scats were identified at localities where feral horse impacts were severe, and 34% of moderate horse impact sites had no rat scats.3. Sites with low horse impacts had little impact on Broadtoothed Rat occurrence.4. The decline in occupancy with increasing horse impacts suggests that feral horse impacts drive local population extinctions of Broad-toothed Rats.5. Declines in Broad-tooted Rat come about because Rat depends on dense vegetation cover in winter for insulation and to form subnivean space beneath the snow pack to allow for foraging. Loss of cover through grazing and trampling damages vegetation and the ability of the Rat to survive over winter months.
Ward-Jones, J., Pulsford, I., Thackway, R., Bishwokarma, D., & Freudenberger, D. (2019). Impacts of feral horses and deer on an endangered woodland of Kosciuszko National Park. Ecological management & restoration, 20(1), 37-46.
Surveyed fenced exclosures and paired grazed plots that were first established and surveyed in 1984 and re-surveyed in 1987, to investigate the severity of the impacts of feral horse (Equus caballus) and deer (Dama dama and Rusa unicolor) in 2013 and 2017/18.
1. Total herbivore dung density increased fourfold since the 1987, mostly attributed to horses - no evidence of horses or deer from 1987 dung surveys. In 2018, 84% of the dung was from horses, 13% from deer, 1% from rabbits and 2% from macropods.2. Greater cover of understorey plants and denser, taller midstorey inside the exclosures.3. Sparser vegetation cover and more extensive soil erosion outside exclosures4. Total number of invertebrates captured in small pitfall traps was nearly twice as many within the exclosures compared to horse-grazed plots. 5. Neglible change in density of overstorey (White Cypress Pine) over 34 years
Williams, P. R. J. (2019). Science as an antidote to horse trading in the Australian Alps. Ecological Management & Restoration, 20(1), 4-6.
Review scientific basis for reducing feral horse numbers in Australian Alps by examining grazing impacts on natural values and feral horse ecology
Studies show deleterious impacts of livestock grazing on alpine ecosystems and their conservation values. Grazing resulted in very high levels of damage to vegetation and soils, requiring $10M taxpayer investment in rehabilitation in the Australian Alps.There is no evidence to support previous claim that horses ‘can roam without causing significant environmental harm’ as they are free ranging and cannot be kept in one place away from sensitive ecosystems, they graze selectively often in rare and endangered grasslands and herbfields, travel long distances that results in soil and water degradation, and damage wetlands when they visit them to drink.
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”
Allan H. and Lintermans M. (2018) The threat from feral horses to a critically endangered fish. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 88–89. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on the single known population of the nationally endangered Stocky Galaxias in Kosciuszko National Park
1. "Wild horses are abundant in the Tantangara area and establish/use well-worn trails throughout the Tantangara Creek catchment. These trails commonly cross Tantangara Creek where Stocky Galaxias is found. At such crossings, bankside vegetation is largely absent, bank structure is damaged, the stream is wide and shallow, and fine gravels and silt have filled an otherwise boulder- and cobble-dominated substrate. "2. "Observations downstream of horse crossings show accumulations of fine sediment, almost certainly mobilised by horse damage (pugging, trampling, bank slumping, runoff from trails). These sediment accumulations are generally less severe or absent in areas further downstream, or immediately upstream of crossings. The extremely small current distribution of Stocky Galaxias magnifies the importance of instream and riparian habitat degradation from feral horses. 3. "rocky substrates and clean spaces between stones appear important for Stocky Galaxias spawning. Sedimentation reduces available spawning habitat and can smother and kill fish eggs. The long incubation time of Stocky Galaxias eggsmeans the species is particularly vulnerable to sedimentation. Direct damage by horse trampling could also impact egg and larvae survival."
Bates, H., 2018. Indirect impacts of the feral horse on the mountain pygmy-possum. In:Worboys, G.L., Driscoll, D., Crabb, P. (Eds.), Feral Horse Impacts: The KosciuszkoScience Conference – Conference Abstracts. 2018. Australian Academy of Science,The Australian National University and Deakin University Canberra, pp. p76–p78.
To summarize the possible impacts of feral horses on two populations of the nationally endangered Mountain Pygmy-possum (Burramys parvus) in Kosciuszko National Park
Feral horses are currently not abundant around areas of Mountain Pygmy-possum habitat. However, they have been seen grazing among boulder-fields and feeding on sedges in lakes on the western fall of Mt Kosciuszko, on the Summit Road habitat site 2 km from Charlotte Pass and at Dead Horse Gap. Horse presence (dung heaps) is evident around the Rough Creek habitat site in Northern Kosciuszko National Park. Expansion of horse numbers throughoutthe alpine area and parts of the Jagungal Wilderness Area (e.g. Gungartan) can be expected without effective control, particularly with continuing climate change–induced droughts. Resulting impacts include trampling of alpine shrubs and sedimentation of streams, evident where horses are currently abundant. This is likely to cause loss of food resources and enhancement of feral predator impacts through reduced cover and creation of trails in summer and disruption of the sub-nivean space in winter.
Driscoll, D.A., Worboys, G.L., Allan, H., Banks, S.C., Beeton, N.J., Cherubin, R.C., Doherty, T.S., Finlayson, C.M., Green, K., Hartley, R., Hope, G., Johnson, C.N., Lintermans, M., Mackey, B., Paull, D.J., Pittock, J., Porfirio, L.L., Ritchie, E.G., Sato, C.F., Scheele, B.C., Slattery, D.A., Venn, S., Watson, D., Watson, M. and Williams, R.M. (2019), Impacts of feral horses in the Australian Alps and evidence?based solutions. Ecol Manag Restor, 20: 63-72. doi:10.1111/emr.12357
To summarize research addressing the impacts of feral horses on Alpine National Park in Victoria, Kosciuszko National Park in NSW and Namadgi National Park in the Australian Capital Territory, and to examine the case for aerial culling, including evaluating the ethical and social context
New evidence indicates that feral horses in Australia’s alpine parks systems endanger threatened species and damage critically endangered bog communities that could take millennia to recover. These impacts are not confounded by effects of deer and accumulate over time, even when only a small number of feral horses (~100) are present. Trapping alone does not control feral horse numbers. Aerial culling is needed to cost-effectively and humanely control feral horses. The relatively small amount of suffering feral horses experience during a cull is outweighed by (i) avoiding suffering and death of horses from starvation and thirst, (ii) avoiding the suffering of native animals displaced by horses and (iii) avoiding the ethical concerns of driving threatened species towards extinction. As a result of ineffective management, horse populations are now expanding and causing well-documented damage to Australia’s alpine parks, placing at risk almost $10M spent on restoration after livestock grazing ended.
Hope G. (2018) Feral horse damage to soft terrain: bogs and fens in the Snowy Mountains. In : Feral Horse Impacts: The Kosciuszko Science Conference (eds G. L. Worboys, D. A. Driscoll and P. Crabb) pp. 54– 56. Australian Academy of Science; The Australian National University; Fenner School of Environment and Society; and Deakin University, Canberra.
To summarize the possible impacts of feral horses on high country bogs and fens in Kosciuszko National Park
Examples of stream widening, incision of peatlands, pugged peat and drying peat at risk from fire have been described in all areas of horse occurrence in Kosciuszko National Park. Soft moss hummocks that are key to raised water tables are readily destroyed by trampling, thus losing the mosaic of small pools that are essential to frog breeding success. During drier periods, the soft sedges of fens are grazed and horse trackways become drainage lines that concentrate flows.
Prober, S. M. & Thiele, K. R. (2007). Assessment of Impacts of Feral Horses (Equus caballus) in the Australian Alps: An experimental monitoring program in the Cobberas-Tingaringy Unit of the Alpine National Park: Progress 1999 to 2005. Unpublished report to Parks Victoria.
To monitor the effects of exclosure from feral horses on floristic composition and structure of favoured grazing areas (grasslands), and on bank condition and disturbance of streams draining these areas.
The differences between exclosures were significant for vegetation height, stream depth and stream pugging, with feral-horses excluded plots having increased vegetation height, stream depth, and pugging. At a fine-scale, unfenced plots had higher overall plant species richness. Exclusion of horses had no effect on weed cover or richness
Tolsma A. D. & Shannon J. (2018) Assessing the Impacts of Feral Horses on the Bogong High Plains, Victoria. Arthur Rylah Institute for Environmental Research. Unpublished client report for Parks Victoria, Department of Environment, Land, Water and Planning, Heidelberg, Victoria.
This project aimed to visit a range of locations across the Bogong High Plains to document the nature and extent of feral horse impacts, and as far as possible, how these impacts have changed over the last decade.
In 2017 resurveyed 56 sites that were originally surveyed in 2006-8. Less than 4% of bogs had feral horse impacts in 2006-8, but 32% had been impacted in 2017. This damage accumulated with only around 100 feral horses on the Bogong High Plains. “There is unlikely to be an acceptable, minimum population size that would avoid incremental, on-going degradation.”