The blame game and the science

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

The lack of research

Reference document

https://pestsmart.org.au/wp-content/uploads/sites/3/2020/06/FeralHorse.pdf

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.” - reference-

 

https://theconversation.com/australian-endangered-species-southern-corroboree-frog-16189

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

https://bioone.org/journals/wildlife-research/volume-46/issue-2/WR18093/Feral-horse-impacts-on-corroboree-frog-habitat-in-the-Australian/10.1071/WR18093.short

 

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 -

 

https://theconversation.com/our-field-cameras-melted-in-the-bushfires-when-we-opened-them-the-results-were-startling-139922

 

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 -

 

https://www.environment.gov.au/resource/smoky-mouse-pseudomys-fumeus

 

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.

Reference-

 

https://www.environment.act.gov.au/__data/assets/pdf_file/0006/995532/Technical-Report-35-BT-Rat-survey.pdf

 

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 –

https://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=64721

 

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 -

 

https://en.m.wikipedia.org/wiki/Procoptodon

 

Humans damage

 

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.“ from document-

 

https://sustainabledevelopment.un.org/content/documents/1124landuse.pdf

 

https://www.google.com/amp/s/amp.abc.net.au/article/8141094

 

https://npansw.org.au/2020/05/15/snowy-2-0-doesnt-stack-up/

 

“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” reference-

 

https://www.climatechangeinaustralia.gov.au/media/ccia/2.1.6/cms_page_media/168/CCIA_2015_NRM_TechnicalReport_WEB.pdf

 

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.

Reference-

https://www.researchgate.net/profile/Neville_Walsh/publication/237372947_The_flora_of_Nungar_Plain_a_treeless_sub-alpine_frost_hollow_in_Kosciuszko_National_Park/links/53e166810cf2d79877a952b1/The-flora-of-Nungar-Plain-a-treeless-sub-alpine-frost-hollow-in-Kosciuszko-National-Park.pdf?origin=publication_detail

 

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-

 

https://www.parks.vic.gov.au/-/media/project/pv/main/parks/documents/management-plans/barmah-national-park-and-barmah-forest-ramsar-site-strategic-action-plan-2020-2023.pdf?la=en&hash=E130D0B2C8E9C9E22B349EC9148F9AA99ED09BAA

 

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-

 

https://pestsmart.org.au/wp-content/uploads/sites/3/2020/06/Managing-vertebrate-pests-feral-pigs.pdf

 

https://www.environment.nsw.gov.au/Topics/Animals-and-plants/Threatened-species/NSW-Threatened-Species-Scientific-Committee/Determinations/Final-determinations/2004-2007/Predation-habitat-degradation-disease-transmission-by-feral-pigs-key-threatening-process-listing

 

Wild Deer Damage

 

Reference document -

https://www.parks.vic.gov.au/-/media/project/pv/main/parks/documents/management-plans/barmah-national-park-and-barmah-forest-ramsar-site-strategic-action-plan-2020-2023.pdf?la=en&hash=E130D0B2C8E9C9E22B349EC9148F9AA99ED09BAA

 

 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.”

 

Reference-

http://vnpa.org.au/ecosystem-decline-inquiry/

 

“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.”

 

https://www.abc.net.au/news/2017-07-21/harrietville-project-looks-at-how-to-deal-with-deer/8732414

https://www.abc.net.au/news/2017-03-31/deer-hunters-cull-sambar-deer-in-alpine-national-park/8396774

https://www.theage.com.au/national/victoria/feral-deer-damaging-alpine-national-park-to-be-culled-in-parks-victoria-trial-20150722-gii2th.html

https://www.theland.com.au/story/3872462/deer-plague-hits-hip-pocket/

 

https://www.environment.nsw.gov.au/topics/animals-and-plants/threatened-species/nsw-threatened-species-scientific-committee/determinations/final-determinations/2004-2007/herbivory-and-environmental-degradation-caused-by-feral-deer-key-threatening-process-listing

 

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.”

 

https://onlinelibrary.wiley.com/doi/abs/10.1111/mam.12080

 

Rabbit damage

 

https://www.environment.nsw.gov.au/topics/animals-and-plants/threatened-species/nsw-threatened-species-scientific-committee/determinations/final-determinations/2000-2003/competition-and-grazing-by-the-feral-european-rabbit-key-threatening-process-listing

 

Wild Goat damage

 

https://www.environment.nsw.gov.au/topics/animals-and-plants/threatened-species/nsw-threatened-species-scientific-committee/determinations/final-determinations/2004-2007/competition-and-habitat-degradation-by-feral-goats-capra-hircus-key-threatening-process-listing