Mt Buller Masterplan Addendum – Mt Stirling Offset Site
The Mt Stirling offset site is within the Mount Stirling Alpine Resort. It extends across 352.3406 hectares, of which 25.0352 hectares concurrently provides EPBC Act offsets for the Alpine Sphagnum Bogs and Associated Fens threatened ecological community. The offset site includes all treeless alpine vegetation and most of the treed sub-alpine vegetation within the Resort.
Native vegetation within the offset site is contiguous with native vegetation in the broader Resort and into neighbouring State Forest and National Park. Ecological Vegetation Classes (EVCs) within the offset site include:
§ Montane Damp Forest (EVC 38)
§ Montane Riparian Thicket (EVC 41)
§ Sub-alpine Shrubland (EVC 42)
§ Sub-alpine Woodland (EVC 43)
§ Alpine Coniferous Shrubland (EVC 156)
§ Sub-alpine Wet Heathland (EVC 210)
§ Sub-alpine Wet Sedgeland (EVC 917)
§ Alpine Grassland (EVC 1001)
§ Alpine Grassy Heathland (EVC 1004).
The current condition of native vegetation within the offset site is high, ranging from 63.27 to 89.18 out of 100. Overall weed cover is low, being less than or equal to 5% weed cover for all vegetation types, and understorey species diversity is relatively high, with understorey scores ranging from 15 to 20 out of 25. Beyond historic cattle grazing and the establishment of trails through the offset site, the vegetation has remained relatively undisturbed by human activity. Approximately two thirds of the offset site was burnt by bushfire in 2007, which has had a lasting reduction on canopy cover and the density of large trees within the Sub-alpine Woodland. Any logging that took place in the area was predominately confined to montane forests at lower elevation, outside of the offset site. The major current threats to the condition of the offset site are pest animals, weeds, and unrestricted recreational use.
Established pest animals include deer, rabbits, foxes, and cats. Sambar Deer Cervus unicolor cause damage within the offset site by forming tracks through all vegetation types and by forming wallows in wet areas, particularly drainage lines and areas that are synonymous with the Alpine Bog community (i.e., Sub-alpine Wet Heathland and Sub-alpine Wet Sedgeland). Sambar Deer also act as vectors for weed propagules, which readily establish in the disturbed ground that Sambar Deer leave behind. European Rabbit Oryctolagus cuniculus activity is limited by microclimate and geology. Within the offset site, the species appears to be largely restricted to open treeless vegetation (Alpine Grassland and Sub-alpine Grassy Heathland) and does not form warrens. Red Fox Vulpes vulpes and Feral Cat Felis catus are known from incidental records (scats, sightings, and photos) to occur within the offset site, although densities of these species are thought to be low, and no den sites are known to occur within the offset site. Other potential pest animals that are not currently known to occur within the offset site include feral horses, pigs, and goats. These pest animals would cause considerable damage to the condition of the offset site if they became established.
Across the entire offset site, total weed cover is less than 5% and high threat weed cover is negligible
(less than 1%). High threat weeds established within the offset site include:
§ Apple Malus pumila, Musk Monkey-flower Erythranthe moschata, Jointed Rush Juncus
articulatus, Prunus Prunus spp. and Grey Sallow Salix cinerea, mainly restricted to wet areas,
such as drainage lines, Sub-alpine Wet Heathland and Sub-alpine Wet Sedgeland, particularly
in the vicinity of deer wallows.
§ Blackberry Rubus anglocandicans, Spear Thistle Cirsium vulgare and St John's Wort
Hypericum perforatum subsp. veronese, mainly restricted to the margins of tracks and trails,
particularly tracks formed by deer.
Some of these weeds are likely to have been introduced and/or spread by historic cattle grazing, which occurred at Mount Stirling as recently as 2006/2007. Currently, there is a clear correlation between the spread of these high threat weeds and deer activity.
The offset site is used for recreational purposes, such as hiking, cross-country skiing, mountain biking, horse riding, four-wheel driving, and hunting. For the most part, these activities are restricted to defined areas within the offset site. Hiking, skiing, mountain biking and horse riding occur along existing management tracks and trails, such as Stirling Trail, West Summit Trail, East Summit Trail, and Stonefly Trail. Skiers are permitted further afield (e.g., into Stanley Bowl or Dugout Bowl) when there is good snow coverage (and therefore less risk of damage to native vegetation). Four-wheel driving is confined to the Howqua Gap Trail and Clear Hills Track (a continuation of the Howqua Gap Trail). These tracks connect Craigs Hut in Mansfield State Forest north-east of the offset site with Howqua Gap on the Circuit Road south-west of the offset site, passing approximately 100 metres east of the Mount Stirling summit. Visitors to Mount Stirling also make use of the established alpine huts for shelter. Geelong Grammar School Hut and Bluff Spur Hut are within the offset site, approximately 400 metre north-east and 450 metres west of the summit respectively. King Spur Hut (also known as Hut 36) is located along Stirling Trail on the boundary of the offset site (and boundary of the EPBC Act offset area). If not properly managed, recreational activities pose a threat to the offset site and have the potential to result in trampling/removal of native vegetation, erosion and the spread of weeds and disease (e.g. Cinnamon Fungus Phytophthora cinnamomi).
The threats outlined above are inter-related and can be managed through a sustained management
effort. Land adjoining the offset site, including the State Forest and National Park, share the same
management issues. There is no permanent fencing around or within the offset site. Temporary fencing will be established where necessary to manage recreational activities and to control pest animals, such as deer, particularly around sensitive alpine bogs. A fence around the offset sites is not feasible or desirable from a management or ecological perspective, given that the proposed offset area is contiguous with native vegetation in the broader resort and into Mansfield State Forest and the Alpine National Park. Such a fence would be detrimental to the movement of desirable native species, such as wallabies or dingoes.
Existing trails within and around the offset site will be maintained to provide access to manage the offset site. Access into the offset site is primarily from Howqua Gap to the south via Howqua Gap Trail or from Telephone Box Junction in the north-west via Stirling Trail. Access is also possible from Mansfield State Forest in the north-east via Clear Hills Track. Accessibility within the offset site is provided by:
§ Howqua Gap Trail and Clear Hills Track, which will remain seasonally open to the public and
accessible by four-wheel drive or all-terrain vehicle (ATV). These tracks are known to be prone to erosion, are corridors for the movement of weeds and will require continued remediation and management.
§ East Summit Trail, River Spur Trail, South Summit Trail, Bluff Spur Trail, West Summit Trail
and Stirling Trail will remain permanently closed to the public and accessed primarily by ATV, to minimise impacts on low-growing native vegetation across these trails and reduce the risk of erosion.
§ Thirteen Mile Spur Track, which forms the southern boundary of the offset site, is mostly
overgrown and accessible on foot only (not by vehicle).
§ Existing walking, mountain biking and/or horse trails, such as Stonefly Trail and the pedestrian trails to the summit and false summit of Mount Stirling.
The offset site includes areas of very steep terrain that are only accessible on foot through vegetation or from the air. Many of the threats to the condition of the offset site (such as rabbits, weeds, and recreational pressures) are within proximity to existing tracks/trails and may even be associated with the tracks/trails themselves (such as weeds spreading along trail edges or unauthorised access being obtained to the offset site from existing tracks). However, the key immediate threat to the offset site is deer, which will need to be managed across the entire offset site, particularly in sensitive alpine bogs and drainage lines that are only accessible on foot or from the air.
Copies of both the State and Federal Offset Management Plans can be accessed here: