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

The Ecology of Wild Horses and their Environmental Impact in the Victorian Alps May 2013(tracks, compaction, trampling, pugging and stream bank slumping) was observed in 67% (70 of 104)of the mossbeds assessed that year. Tolsma argued that on-going activity by wild horses is of greatconcern in the east Alps of Victoria. In the East Alps Unit of the ANP, 97% (63 of 65) of peatlandsystems were found to be impacted (i.e. compacted, trampled or pugged) by wild horses (Tolsma2008b).• In 2011 the AALC commenced a project that aims to quantify the impacts of wild horses on uplandstreams and wetlands in the Australian Alps. The results of this study will be available in autumn 2013and will provide further evidence of the impacts of wild horses on sensitive environments.A number of protected areas regionally, nationally and internationally recognise that wild horses have anegative impact on the environment and have developed strategies to address these impacts (Table 2).Table 2: Examples of wild horse management plans and strategies and their ecological rationaleRegion Wild horse strategy Rationale for the plan (ecological)AANPsNationalNewZealandKosciuszko National Park HorseManagement Plan.Namadgi National Park Feral horseManagement Plan.Guy Fawkes River National Park:Horse Management Plan.Feral horse Management Plan forOxley Wild Rivers National ParkProtecting the natural & culturalvalues of Carnavon National Park:A plan to manage wild horses &other pest animalsKaimanawa Wild Horses Plan.The National Parks & Wildlife Service has legislative responsibility toprotect native habitats & wildlife within its reserves & a responsibilityto minimise the impact of introduced species, including wild horses.The 2006 Plan of Management called for a wild horse managementplan & the exclusion of wild horses from key areas. (NSW NPWS 2008).The plan aims to minimise the negative impact of wild horses includinggrazing on sensitive vegetation, trampling of streambanks, trailformation & erosion. These can lead to draining of entire bog systems,loss of habitat for threatened species & silt deposition downstream.(ACT Government 2007).The National Parks & Wildlife Service has legislative responsibility toprotect native habitats & wildlife within its reserves & a responsibilityto minimise the impact of introduced species, including wild horses(NSW NPWS 2006a). Wild horses are an introduced species that haveadverse impacts on Australian ecosystems with particularly severeconsequences for native fauna & flora (English 2001).Wild horses have been identified as posing a threat to the conservationvalues of the park & water quality. (NSW NPWS 2006b).Queensland Parks & Wildlife Service has a legal obligation to conserve& protect the natural values of Canarvon NP & control threateningprocesses caused by pest species including wild horses. Destructiveimpacts by wild horses have led to: the deterioration of aquaticecosystems & serious landscape dysfunction (losses in biomass,accelerated erosion, soil compaction, altered species composition &vegetation structure & altered fire ecology). (Weaver 2007).Horses have been shown to adversely affect nationally significantecological values. There is a need to eliminate the impacts of horses onimportant conservation values. (DOC 2006).In addition to these wild horse plans and strategies, a series of workshops on wild horse impact andmanagement in the Australian Alps (see: Walters & Hallam 1993; O’Brien & Solomon 2004) and a nationalworkshop (see: Dawson et al. 2006) have demonstrated widespread concern from scientists and practitionersabout the impacts of wild horses in alpine and sub-alpine environments.The impacts that wild horses have on the soils and substrate, peatlands , waterways, vegetation and fauna ofthe Victorian Alps is considered below in greater detail.3.2 Impacts on soil and substrateIt is generally accepted that alpine areas are more susceptible to damage by hard hooved animals such as wildhorses than most other environments, due to their wet fragile soils and slow vegetation growth rates (Whinamet al. 1994). Wild horse trampling and grazing can lead to major changes to the soil, including: pugging, drying,11