The Ecology of Wild Horses and their Environmental ... - Parks Victoria

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The Ecology of Wild Horses and their Environmental Impact in the Victorian Alps May 2013Introduction to Wild Horse Background PapersHorses (Equus caballus) living in unmanaged, wild populations in Australia are generally known by three terms;feral horses, wild horses and brumbies. Any introduced domestic animal that lives in unmanaged, selfsustaining, wild populations is by definition a feral animal. However, some people are uncomfortable with theterm ‘feral’ being associated with horses and prefer the terms ‘wild horse’ or ‘brumby’. ‘Brumby’ is a colloquialterm often used in Australian folklore; however some people believe the term elicits a romanticised view ofhorses and detracts from their environmental impacts. In this series of papers the term ‘wild horse’ will beused, as it is a generally accepted term and clearly refers to un-domesticated horses living in the wild.Horses were introduced to Australia by early European settlers and Australia now has the highest populationof wild horses in the world, with more than 300 000 (Dobbie et al. 1993). Wild horses are a pest species inAustralia, that is, an “animal that has, or has the potential to have, an adverse economic, environmental orsocial/cultural impact” (Natural Resource Management Ministerial Council 2007).Wild horses occur across the Australian Alps and have been identified as a high priority threat to naturalvalues of the region (Coyne 2001). The “degradation and loss of habitat caused by feral horses” is listed as apotentially threatening process under Victoria’s Flora and Fauna Guarantee Act (1988).In Victoria, wild horses occur within the Victorian Alps, with a smaller population present in the Barmah Forest(Wright et al. 2006). This series of three Background Papers will focus on wild horses in the Victorian Alps(Alpine National Park (ANP) and surrounding State forests).The Background Papers investigate the ecology, environmental impacts, human dimensions and managementand control of wild horses in the Victorian Alps. They are arranged in the following order:Background Paper 1: The Ecology of Wild Horses and their Environmental Impact in the Victorian Alps. The firstsection of this paper considers the ecological dimensions of wild horses in the Victorian Alps including theirdistribution, population trends, demography, habitat, diet and mortality factors. The environmental impacts ofwild horses within the region are then considered including their impacts on: soil and substrate, vegetation,peatlands, waterways and fauna. Biosecurity issues are also discussed.Background Paper 2: The Human Dimensions of Wild Horse Management in the Victorian Alps. This paperprovides the social context for wild horse management in the Victorian Alps. A brief history of wild horses inthe region and the major stakeholder groups involved is outlined. The socio-economic and cultural heritagevalues of wild horses are then explored followed by a discussion on public perceptions about wild horses andtheir management in the Victorian Alps. Research from national and international investigations intoperceptions towards wild horses is drawn upon to help unravel the complexity of this value-laden issue.Background Paper 3: Wild Horse Management and Control Methods. This paper considers the management ofwild horses in the Victorian Alps and considers control methods for managing wild horses. An overview of howwild horses have been managed in the Victorian Alps and the legislation and policy framework for wild horsemanagement is provided. The paper explores welfare issues and costs associated with wild horse control,levels of control and control options.This series of papers was prepared based on available literature and research, and, through consultation withexperts where possible. The papers provide a foundation for discussion concerning the future management ofwild horses within the Victorian Alps.1
The Ecology of Wild Horses and their Environmental Impact in the Victorian Alps May 20131. IntroductionIn Victoria wild horses (Equus caballus) occur in the Victorian Alps with a smaller population present in theBarmah Forest, on the Murray River (Menkhorst 1995; Wright et al. 2006). Wild horses are considered asignificant environmental threat to the Victorian Alps (including the Alpine National Park (ANP) and adjacentState forests). The “degradation and loss of habitat caused by feral horses” is listed as a potentially threateningprocess under Victoria’s Flora and Fauna Guarantee Act (1988). This paper will explore the ecologicaldimensions of wild horses in the Victorian Alps and the extent to which they are affecting the natural values ofthe region.Several studies and reviews have been conducted on the ecology and environmental impacts of wild horses invarious parts of the Australian Alps, including: Dyring 1990; Thiele & Prober 1999a, 1999b; Walter 2002, 2003;Walter & Hone 2003; Montague-Drake 2005; Prober & Thiele 2007; Nimmo & Miller 2007; Laake et al. 2008;Dawson 2005, 2009a, 2009b; and Venn et al. 2009. To help unravel the significance of wild horses in theVictorian Alps, information in this paper is also drawn from national and international literature as well asanecdotal information on wild horses in the Victorian Alps.2. Wild horse ecology in the Victorian Alps3.1 Wild horse distributionWild horses in the Australian Alps are relatively isolated from populations elsewhere in Australia. The largestpopulations in Australia occur in dry and tropical environments, mainly in the Northern Territory andQueensland, but also Western Australia and South Australia (Dobbie et al. 1993). In much of Australia, droughtlimits the distribution of wild horses (Dobbie et al. 1993). However, this is not evident in the Australian Alpswhich occupy wetter bioregions with more consistent rainfall (Hobbs & McIntyre 2005). The distribution ofwild horses in Australia has also been strongly influenced by human intervention including farminginfrastructure such as fencing (McKnight 1976).Wild horses were initially introduced into the Australian Alps by European settlers in the 1830s. Graziersmanaged the distribution (and numbers) of wild horses to varying degrees from the mid-1800s up until cattlegrazing ceased early this century (Walter 2002; Foster 2004). Non-human influences on wild horse distributionin the Alps include preferred habitat, geographical barriers and natural events such as severe snow storms, fireand drought (Walter 2002). Between 1990 (Dyring 1990) and 2002 (Walter 2002) wild horse distributionappeared to be relatively stable in the ANP, however, in the past ten years wild horse populations haveexpanded their range in a number of locations, including spreading to new locations on the Bogong High Plains(Dawson 2009). Dawson (2009) also suggests that there is suitable habitat for wild horses in Australian Alpsthat is currently not occupied. Furthermore, it is predicted that with climate change, areas at higher elevationwill become more suitable for wild horses (Dunlop & Brown 2008; Green & Pickering 2002).The largest population of wild horses in the Victorian Alps is in the eastern Alps (east of Omeo) and isconnected to a population in Kosciuszko National Park, NSW to the north (Figures 1 and 2). It extends south tothe Nunniong Plains, as far west as Mt Pinnibar and Buenba Creek, and to Deddick and Amboyne east of theSnowy River. The second, smaller population is on the southern Bogong High Plains, between Falls Creek andMount Hotham, and in the headwaters of the Cobungra, Bundara and Victoria Rivers (Ethos NRM 2012). TheBogong High Plains/Cobungra population is isolated from the Eastern Alps population by around 30km andconsidered to have a lower density of horses than the east Alps population (Ethos NRM 2012) (figure 2). Bothpopulations, while situated predominantly within the ANP, extend into adjacent State forests and reservesand, probably, private land.2
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