The blame game and the science

Author - Joanne Canning, BSc Equine Sports Science, HND Equine Sports Coaching, BHSII

The lack of research

Reference document

Reference Workshop outcomes page -

“Research on feral horses is surprisingly lacking in Australia and would benefit from national leadership and direction. It should: accurately map the distribution and abundance of feral horses; quantify feral horse impact in relation to density and control; evaluate the humaneness and suitability of control techniques; document community and stakeholder perceptions on feral horse impact and management; and assess whether feral horse impacts threaten native species or communities.”

Reference - Summary page

“There is a scarcity of published peer reviewed research on feral horses in Australia. The relationship between feral horse density and damage remains to be quantified in any area, which impedes effective management. Much of the evidence on environmental impacts and population ecology is anecdotal”

Reference- Section 6

“The assumption that an introduced animal is causing damage may not be correct. Feral horses in some places may in fact be beneficial. They may be reducing bushfire fuel loads by removing grass. They may be exerting no negative impact at all and simply providing pleasure for those that love seeing wild horses living free in the bush. Control in this case would be a waste of time and money.”


“In general, although a significant amount of studies have been done on the effects of herbivores on the environment, there are still relatively few studies specifically about the effect of wild horses.”

(Beever, EA and Brussard, PF 2000, Examining ecological consequences of feral horse grazing using exclosures, Western North American Naturalist 60: 236–254.)


This is also the case in Australia. Much of the evidence” of environmental impacts is anecdotal from observational studies, where much of the photographed damage could have been caused by other animals present, as there are very large numbers of wild pigs, deer, goats and rabbits, some considered to be in plague proportions. Wild pigs in particular are known to cause significant damage. This is well evidenced.


Threats to Corroboree Frog


The spread and persistence of chytrid fungus in the population is facilitated by a species living alongside the Corroboree Frog, the Common Eastern Froglet (Crinia signfera). This species appears to sustain high infection levels, but doesnt develop the disease. As a result, it acts as a reservoir host, sustaining the disease in the ecosystem and allowing transmission to other species.”

“An additional threat to the Southern Corroboree Frog is climate change. Reduced precipitation and warmer temperatures are likely to eventually affect breeding pools and vegetation around them. Droughts already result in egg and tadpole deaths, and as the frequency of droughts increases with climate change, the capacity for the Southern Corroboree Frog to recovery greatly reduces.” –



There are few peer-reviewed studies of the impacts of feral horses on ecosystems in this region.” –



We surveyed the scene, calling out: Hey, frog!”. At ponds not severely burnt, reasonable numbers of northern corroboree frogs responded. At badly burnt sites where frogs had been found for 20 years, we were met with silence. The adults there had likely died.” After the fires, heavy rain in denuded burnt catchments produced water runoff laden with sediment. Some frog breeding habitat was eroded and filled with silt and ash. Once-mossy ponds were now gravel and ash.”

They contained a fascinating series of photos. Some revealed how a number of ponds largely escaped the fires, only to be destroyed afterwards by flooding.” - Reference -


The Smoky mouse threats


Major threats to the species include predation by introduced carnivores, habitat changes due to altered fire regimes and dieback caused by the Cinnamon Fungus (Phytophthora cinnamomi), and loss, modification and fragmentation of habitat due to road construction and intensive timber harvesting.” - Reference -


The Broad toothed rat threats


Main threats - Predation by wild cats and foxes

competition and grazing by rabbits

Competition, disease transmission and habitat degradation by wild Pigs

Catastrophic fire events

Global warming causes loss of snow cover resulting in increased exposure to foxes and cats.

Climate change resulting in loss of sub-alpine and alpine habitat, and; spread of the plant root fungus Phytophthora cinnamom

Habitat loss, fragmentation and degradation from roads, ski runs, buildings and recreational activities.



The Alpine Skink

Main Threats –

“Wildfire has the potential to eliminate the species”

“Historically, large tracts of habitat have been lost as alpine resort villages have been constructed and expanded. Construction of dams has destroyed habitat that was almost certainly occupied by the species. Concurrent development of infrastructure such as roads, tracks and ski runs have also destroyed and fragmented habitat. Development of ski runs may have a greater than expected effect on habitat for Alpine She-oak Skinks, as it is more favourable to build ski runs in large, continuous grassy areas that provide a uniform surface. These large grassy areas are the optimal habitat of the Alpine She-oak Skink. “

“Predation by Rats (Rattus rattus), Foxes (Vulpes vulpes), Cats (Felis catus) and Wild Dogs (Canis lupus familiaris) is a current threat.”

Also mentioned are weed invasion, climate change and trampling of habitat by ALL animals.

Reference –


The Hard Hoofed Story


It is constantly said by the anti-Brumby people - The Australian Alps is home to species that occur nowhere else in the world. They have evolved over millions of years and theyre not adapted to the pressures of heavy hard hoofed animals such as horses and deer, who cause so much damage to vegetation, waterways and other habitats” – This is however not true – please see document below for the hard hoofed heavy species that lived in these parts. Reference -


Human damage



The landscape is highly susceptible to a drying, warming climate (Hennessy et al. 2008), and its features and functions will struggle to survive within a climate space that is predicted to no longer exists by 2100 (Williams et al.2007). the effects are expected to be most acutely evident in communities such as wetlands and snow patch vegetation that are dependent on current temperature and precipitation regimes (Pickering et al. 2004, McDougall and Walsh 2007) and in ski resorts that may face closure because of lack of snow (Pickering 2011)

Climate change

Climate change is already affecting the Australian Alps, as evidenced through a 30% reduction in snow cover (Pickering 2011). Because the distribution of flora and fauna is in part determined by snow presence, depth, and persistence, such changes are expected to have substantial impacts on alpine biodiversity (Pickering and Armstrong 2000, McDougall and Walsh 2007). Average temperatures are predicted to increase by 2.9 degrees C by 2050 and rainfall to decrease by 24% over the same period (Hennessy et al. 2008). More frequent and severe droughts are also predicted (Macdonald 2008).

This combination of influences, originating outside the focal system, makes climate a key driver of change. The low-temperature conditions that have created the structure, species mix, and dynamics of the focal system’s alpine and subalpine ecosystems make them highly sensitive to climate change (Spehn et al. 2002). Under a warming climate, alpine ecosystems in particular lack any higher ground to move into and will be under pressure from species currently restricted to lower elevations (Pickering et al. 2004). Snow gum woodlands, for example, are likely to expand into areas that are currently occupied by grassland and heathland vegetation (McDougall 2003, McDougall and Walsh 2007).”

“The effects of climate change will differentially affect components of the alpine and subalpine vegetation mosaic. Alpine and subalpine wetlands are likely to be impacted through more extended periods of drought, increased average and peak temperatures, increased incidence of wildfire, and impacts from new and extant invasive species (Macdonald 2009). Even a small increase in mean ambient temperature is likely to result in the loss of wetlands because of changes in snowfall and snowmelt regimes (Pickering et al. 2004). Heathlands are expected to be resilient to climate change over the next 20 to 30 years with recent experimental work in the Bogong High Plains suggesting that changes in diversity and cover changes will be small rather than transformational (Wahren et al. 2013). Pickering and Armstrong (2000) suggest that heath communities are likely to increase in area as increasing temperatures and declining snow cover favour shrub species over grasses and herbs. “

“Reduced snow cover is expected to have a detrimental effect on alpine fauna. The mountain pygmy-possum, for example, is likely to suffer a contraction in suitable habitat, increased winter mortality, and more competition from low-altitude species (Pickering et al. 2004). Climate change may also affect the breeding success of alpine frog species in ephemeral pools because the pools have the potential to dry before the tadpoles reach metamorphosis (Hunter et al. 2009).”

“Climate change, and the associated reduction in snow cover, is also likely to affect the ski industry and water production. Under high-emission scenarios, the duration of the ski season based on natural snow cover is projected to decline. Across the Victorian ski resorts of Falls Creek and Mt. Hotham, for example the average snow season is forecast to become 5-35 days shorter by 2020 and 20-80 days shorter by 2050 (Bhend et al. 2012). Continuation of the industry will require a significant expansion of artificial snowmaking, which is only likely to be viable in the higher altitude resorts (Pickering et al. 2004, Hennessy et al. 2008). The observed dramatic reduction in winter visitation during poor snow seasons is indicative of the challenges facing Australian alpine resorts (Pickering et al. 2004). Although investment in snowmaking is helping to address these challenges, the resorts are under pressure to identify strategies to develop and market their less economically lucrative summer events and activities (ARCC 2012)”

“The drivers that are most likely to determine the future trajectory of alpine and subalpine landscapes are climate change, associated changes to fire regimes and invasive processes, and the intensity and distribution of recreation and tourism use. A positive reinforcement loop, involving a drier and warmer climate that supports an increased potential for fires, threatens to drive the system into a renewed phase of release and reorganisation. This will favour expansion of heathlands, movement of snow gums into currently treeless areas, changes in composition and location of grasslands, reduction in the extent and functionality of wetlands, and potential loss of snow patch vegetation. Alpine and subalpine grog species will suffer further population reduction and potentially extinction. The endemic mountain pygmy possum and local populations of broad-toothed rat are likely to be impacted by seasonal reduction in available of subnivean habitat and increased predation by foxes.”

Reference –

Ecology and Society: Biodiversity governance and social-ecological system dynamics: transformation in the Australian Alps


Tourism and recreation in protected areas results in a range of indirect impacts on the environment, including facilitating the spread of weeds. This paper examined associations between tourism infrastructure and the diversity and frequency of exotic plants in a large and popular protected are in south-eastern Australia, Kosciuszko National Park. Of the 156 exotic taxa recorded in 18 vegetation surveys between1986 and 2004, 152 were associated with tourism infrastructure, 64 taxa on road verges, 50 in ski resort areas, and a further 66 exclusively in the ski resort gardens. As many exotics become invasive environmental weeds this study highlights the need to limit both introduction of exotic propagules and disturbance to natural vegetation during the construction, maintenance and use of tourism infrastructure in protected areas.


“Tourism infrastructure such as walking tracks can have negative effects on vegetation including in mountain regions. In the alpine area around continental Australia's highest mountain, Mt Kosciuszko (2228 m), there is a range of walking tracks (paved, gravel and raised steel mesh surfaces) in addition to an extensive network of informal/non-hardened tracks. Vegetation characteristics were compared between track types on/under tracks, on the track verge, and in the adjacent native vegetation. For a raised steel mesh walkway there was no difference in vegetation under the walkway, on the verge, and 3 m away. In contrast, for a non-hardened track there was 35% bare ground on the track surface but no other detectable impacts. Gravel and paved tracks had distinct verges largely comprising bare ground and exotic species. For non-hardened tracks there was an estimated 270 m2 of disturbance per km of track. For wide gravel tracks the combined area of bare ground, exotic plants and gravel was estimated as 4290 m2 per km, while for narrow gravel tracks it was estimated as 2940 m2 per km. For paved tracks there was around 2680 m2 per km of damage. In contrast, there was no detectable effect of raised steel mesh walkway on vegetation highlighting some of the benefits of this surface over other track types.”

Reference above-


“Tourism to the alpine area is having a range of negative environmental impacts. Direct impacts include; compaction of soil, erosion, trampling of vegetation, urine and faecal contamination of waterways, particularly glacial lakes, disturbance to wildlife, noise pollution, and increased feral animal activity (Edwards 1977, Keane et al. 1979, Hardie 1993, Virtanen 1993, Good and Grenier 1994, Good 1995, CDT 1997, Parr Smith and Polley 1998, Arkle 2000, Buckley et al. 2000, Scherrer and Pickering 2001, Pickering et al. 2002). Some infrastructure provided for tourism, such as walking tracks and huts are having impacts including compaction of soil, clearing of vegetation, assisting the introduction of alien plants, leaching of nutrients into adjacent areas, and visual impacts (Virtanen 1993, Good and Grenier, 1994, Johnston F. and Pickering 2001a, Pickering et al. 2002).

The spread of weeds is a serious issue for the alpine area. Gravel roads and walking tracks combined with regular pedestrian and vehicle (bike and motor vehicle) disturbance appear to favour weeds such as yarrow (Achillea millefolium), white clover (Trifolium repens), browntop bent (Agrostis capillaris), flat weed (Hypochoeris radicata), cocksfoot (Dactylis glomerata), dandelion (Taraxacum officinale) and pellet clover (Trifolium ambiguum, Mallen-Cooper 1990, Johnston F. and Pickering 2001a, 2001b, Pickering and Hill unpublished data).

Research has shown that weeds readily colonize gravel track verges and road disturbance sites. This results in a bright-green weed verge commonly found on parts of the gravel-based and paved tourist walking track system in the alpine area. Given that weeds are still spreading in areas of natural and human disturbance (Mallen-Cooper 1990, Johnston F. and Pickering 2001a, 2001b), limiting the spread of these weeds should be a key conservation goal. 

Other developing management challenges include limiting the spread of new tracks and erosion areas caused through overuse, and preventing trampling disturbance to the most sensitive of the plant communities, such as the wetland and short alpine herbfield. Human waste also contributes to increased nutrification and contamination of pristine waterways, and has negative impacts on the tourism experience. Temporary toilets at Rawson Pass have helped to deal with some of the problems of human waste, but not adequately (Leary 2000). The withdrawal of camping from within the catchment areas of the glacial lakes has also helped, but increasing usage of other areas by campers may result in new areas being impacted.”

Reference -


See also –


Introduction to the Special Activation Precinct – Snowy Mountains –


Introducing the Snowy Mountains Special Activation Precinct -


Snowy Monaro destination management plan –


It is estimated that the human footprint has affected 83% of the global terrestrial land surface and has degraded about 60% of the ecosystems services in the past 50 years alone. Land use and land cover (LUCC) change has been the most visible indicator of the human footprint and the most important driver of loss of biodiversity and other forms of land degradation.



“Soil moisture and runoff projections are strongly influenced by projected changes in rainfall (Sections 7.7.1, 7.7.2), but tend toward decrease because of projected increases in potential evapotranspiration. Changes in runoff are generally 2-3 times larger than the relevant rainfall change”



Wild Pig Damage


While searching for populations of threatened plant species in the Kiandra area between 1999 and 2001, we noticed considerable damage to sub-alpine treeless vegetation by pigs. Most damage was recorded in dry grassland communities and was evidenced by denuded circles up to 20 m in diameter. Some of these bare circles appeared to have been scoured more than once, judging by the varying amount of regeneration within them.”

A group of 15 pigs and piglets was observed in Nungar Plain during the survey. Damage to vegetation by pigs is obvious and extensive. Herb-rich grassland communities are the worst-affected. Rooting is localised but very thorough.



Riparian and wetland habitats are attractive to feral pigs where they can cause serious habitat degradation by rooting in the soil in search of food, and can also prey on the eggs and chicks of nesting water birds in wetlands.” Reference-


Feral pigs disperse seeds of weed species, and in the process of rooting up the ground they trample vegetation and extensively disturb the soil. In addition, regular wallowing and digging of dust-beds can impact on terrestrial and aquatic systems through erosion, siltation and increased turbidity.” reference-


Wild Deer Damage


Reference document -


 Deer degrade ecosystem quality through grazing, browsing and trampling of vegetation, ringbarking trees, as well as dispersing weed seeds and enriching nutrient levels. They also cause soil disturbance in creeks, wetlands and swamps, where they wallow in mud.”




“Over a million deer are wreaking havoc in Victoria’s state forests and national parks, and instead of being managed as a serious pest, deer are oddly protected under the Wildlife Act 1975 in order to support hunting interests.”


Wild Cats and the risk to native Fauna


“In Victoria foxes and cats have already contributed to the extinction of a number of small native marsupials and are threat to many remaining threatened species.”


Rabbit damage


Wild Goat damage