Chapter 2Overview of feral horse populations
Overview
2.1The Australian Alps constitute a large area made up of 11 national parks and nature reserves across New South Wales, Victoria and the ACT. The individual parks and reserves which make up the Australian Alps National Parks and Reserves are individually gazetted and managed by the relevant state and territory governments. Despite the term ‘national park’, these are not located on Commonwealth land and primary responsibility for their management rests with the states and territory.
2.2The area is more than 1.6 million hectares of public land, and includes high altitude peaks and plateaus, glacial lakes and alpine and sub-alpine ecosystems. The Australian Alps are part of the Great Dividing Range and contain the Snowy Mountains in New South Wales and the ACT, and the Victorian Alps.
2.3The fragile Australian Alpine ecosystem has been listed for protection under a variety of provisions of the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act), including specific listings for plant and animal species, certain ecological communities, and the parks and reserves within the alpine area.
2.4Australia’s tallest mountain, Mount Kosciuszko, is within Kosciuszko National Park (KNP), which is managed by the NSW National Parks and Wildlife Service (NPWS). KNP is around 690,000 hectares and is the largest national park in NSW.
2.5Figure 2.1 is a map of the Australian Alps National Parks and Reserves, which shows the state borders and boundaries of the heritage place listing.
Figure 2.1Map of the Australian Alps National Parks and Reserves National Heritage place
Source: Department of Climate Change, Energy, the Environment and Water (DCCEEW), Submission 23, p. 21.
Feral horses (Equus caballus)
2.6Feral horses are an introduced species. They are horses that are from domesticated stock but are free-roaming, rather than wild animals. Feral horses are considered to be a pest animal by the Australian Government because of the damage they can do to the environment.
2.7Australia has the world’s largest population of feral horses. The most recent nation-wide assessment is from 2011, which found an estimated 400,000 feral horses in locations across Australia (see Figure 2.2). As discussed below, in 2019 there were around 25,000 present in the Australian Alps. Feral horses inhabit a variety of ecosystems, from semi-arid to tropical grasslands to alpine areas. They prefer grasslands and shrublands with water and pasture.
2.8The only significant threats to feral horses are drought and bushfire. This means that active management is required for overall population control or for eradication. The population of feral horses in the Australian Alps is rapidly increasing at a rate of 15 to 20 per cent per annum.
2.9Feral horse populations in the Australian Alps are particularly prevalent in NSW, with populations present in 53 per cent of KNP.
Figure 2.2Distribution of feral horses in Australia, 2000
Source: Department of Sustainability, Environment, Water, Population and Communities (DSEWPC), 2011
2.10In the 1830s, Europeans entered the Australian Alps region and used horses for travel and moving stock. The NSW Government stated that:
At times, domesticated horses would escape or were released during drought or to improve the quality of mobs, and feral horses became established in the mountains, including areas that are now within Kosciuszko National Park.
2.11Until relatively recently, numbers of feral horses have been kept low in the Australian Alps over time, primarily through intervention by stockmen and people capturing horses for meat or hide. Control of feral horse populations by shooting, trapping and ‘brumby running’ and roping was undertaken from time to time.
2.12Feral horses form small social units of either a dominant stallion accompanying one to three mares and offspring, or a bachelor group. Groups of mares and offspring prefer areas with steady access to water and have territories they tend to stay in. Bachelor groups can range more widely, up to 88 square kilometres. Feral horses breed in the spring to summer and have a gestation period of around 11 months, producing one foal every two years.
Feral horse population estimates
2.13Estimates of feral horse populations in the Australian Alps have been provided by scientific aerial studies of the area since 2001, and are conducted every five years. Additional, more targeted surveys of KNP have also been undertaken.
Australian Alps
2.14The first standardised surveys of feral horse numbers in the NSW and Victorian Australian Alps national parks were funded by the Australian Alps National Parks Co-operative Management Program (Alps program). Surveys conducted in 2014 and 2019 used updated international best practice methods for population surveys of large animals from the air (see Table 2.1).
Table 2.1Results from surveys conducted for the Australian Alps
| | | |
2001 | 2,789 | 1.86 | 5,187 |
2003 | 2,717 | 0.87 | 2,363 |
2009 | 2,860 | 2.69 | 7,693 |
2014 | 5,429 | 1.70 | 9,187 |
2019 | 7,443 | 3.40 | 25,318 |
Source: Estimated feral horse population, 2001–2019; data is sourced from the Independent Technical Reference Group Final Report (2016), Table 2, and the 2019 Alps survey results.
2.15Professor Chris Johnson, a member of the Threatened Species Scientific Committee (TSSC), told the committee that due to the reproduction rate, in five years’ time the population of feral horses in the Australian Alps would double.
2.16The next major aerial survey of the Australian Alps parks is due in 2024.
Kosciuszko National Park
2.17Surveys were conducted in 2020 and 2022 for KNP specifically, and were peer‑reviewed by CSIRO and the Queensland Department of Agriculture and Fisheries.
2.18In 2020, the KNP survey estimated that the feral horse population in the park was 14,380 (with the 95 per cent confidence interval being 8,798 to 22,555). Two years later, the KNP survey estimated that feral horse numbers had increased to 18,814 (with the 95 per cent confidence interval of 14,501 to 23,535).
2.19The 2022 survey’s key findings were:
the highest density of horses is in the north of the park;
there was an increase in the ratio of foals to adult horses in 2022 compared to the numbers observed in 2020; and
seasonal conditions, such as drought and bushfires, may influence the population size.
2.20The Public Service Association of NSW (PSA NSW) provided Figure 2.3, which shows the sharp increase in the total population of feral horses in KNP from 2000 to 2022, and displays: the population trendline; the removals that were undertaken; and, the removals required to prevent population growth.
Figure 2.3Population vs removal in Kosciuszko National Park
Source: Public Service Association NSW, Submission 20, p. 7.
2.21The survey design used for the aerial surveys was questioned by several inquiry participants. Some submitters stated that the current estimates of feral horse populations in the Australian Alps were incorrect, with numbers ranging from 2,000 to 5,000.
2.22For instance, the Brumby Action Group set out its concerns, stating that the distance methodology used has ‘produced estimates that are scientifically and biologically not possible for the species’:
The survey population numbers have been strenuously disputed for many years by stakeholders, locals to the Alpine High Country and Brumby advocates, as the methodology used is inappropriate for moving animals, and has returned false numbers.
2.23The Snowy Mountains Horse Riders Association also disputed the survey methodology, and estimated the number of feral horses to be much lower than the survey results had shown:
The local community with generational knowledge and intimate landscape experience of the park and its horses, strongly dispute these current ridiculous numbers. The local community believe that the true population estimate is currently in 2023 up to 4000 – 5000 horses in the whole of KNP at most!
2.24Ms Claire Galea, an independent biostatistician, outlined her concerns over the methodology applied by the Alps and KNP surveys, and argued that there were insufficient clusters of feral horses to enable the methodology to be used.
2.25In 2016, the Independent Technical Reference Group (ITRG), formed by the NPWS to provide independent and rigorous scientific and technical advice to the NSW Office of Environment and Heritage (OEH) and the NPWS on the management of wild horses within KNP, issued its final report. The ITRG noted it could not come to a conclusion about the trends in density of feral horse populations:
In conclusion, differences in survey area, design and analysis between the various surveys make it impossible for the ITRG to infer trends over time in the overall density of horses.
2.26Despite these concerns, the NSW Government remains confident in the survey results, and noted that there is a high confidence interval in the estimate of the population:
Information on the number of feral horses across the Australian Alps and in Kosciuszko National Park has significantly improved over time. While design and scope have been adjusted in response to survey technique improvements and to focus specifically on Kosciuszko National Park, the results consistently demonstrate a clear and significant expansion in the size and distribution of feral horses across survey periods.
2.27The TSSC stated that the surveys ‘follow best practice in counting animals’, which acknowledges that the surveyor does not see every animal, and employs a methodology to account for this. Professor Johnson, a member of the TSSC, explained that:
Some people don't like the figures because there is always a range of values—a lower limit and an upper limit—but this is what science does: we try to quantify uncertainty, so that we know what we know and how confident we can be on that. I think it actually is a point in favour of those surveys that they provide those confidence bounds. However you look at them, they're showing an increase, and it's the increasing trend that is the thing we should be most concerned about. Whatever the exact number of horses [in KNP] is now, whether it's 14,000 or 19,000, as I say, we've got clear evidence of an increasing trend which will double that number in the near future.
Victoria and the ACT
2.28Parks Victoria stated that from the most recent surveys, there are approximately 5,000 horses in the Eastern Alps section of the Alpine National Park, and approximately 100 horses on the Bogong High Plains area of the Alpine National Park. Parks Victoria has conducted aerial surveys of the feral horse population on the Bogong High Plains every two to three years since 2005, and an aerial survey was most recently conducted of the Eastern Alps in 2021.
2.29The Invasive Species Council estimated, however, that in the Bogong High Plains in the Victorian Alps, ‘we've gone from about 52 to 250 horses within five years, which is similarly looking at that exponential growth—about a 130 per cent increase’.
2.30Although feral horses on occasions travel into the ACT from NSW, due to effective management strategies there is currently no known permanent population in the ACT.
Committee comment
2.31The committee understands that the population estimates for the Australian Alps, and Kosciuszko National Park (KNP) to be backed by robust and peer‑reviewed scientific methodology. While noting some dissenting opinions, the methods are widely used by the scientific community, and is supported by the TSSC.
2.32The committee further notes, that regardless of the exact feral horse numbers in the Australian Alps, the demonstrable and visible negative impacts of the current population, and its upwards trend, warrant urgent action as set out in following chapters.
2.33On a broader scale, the committee notes that Australia has the world’s largest population of feral horses, which has a reproduction rate of around 15 to 20 per cent per annum. It is therefore surprising that the national population estimate is more than a decade old. Given the high historic number and the rapid rate of reproduction, the committee considers that the impact of feral horses is not well understood at the national level. This is likely to affect the ability to tackle this issue through key threatening processes and threat abatement plans.
2.34The committee therefore urges the Department of Climate Change, Energy, the Environment and Water (DCCEEW) to take a leadership role to establish the population and impacts of feral horses across Australia. This would facilitate an accurate snapshot of the current population and its locations, and allow the Commonwealth, in consultation with the relevant state and territory jurisdictions, to address the issue in a more coordinated way.
2.35Further committee comment and recommendations are made in Chapter 7.