Naomi E Davis
The introduction of deer to Australia began in the mid-1800s and six deer species are now established in the wild: sambar (Rusa unicolor), red deer (Cervus elaphus), rusa deer (Rusa timorensis), fallow deer (Dama dama), chital (Axis axis) and hog deer (Axis porcinus) (Bentley 1998). Deer can have substantial deleterious impacts on natural ecosystems (Cote et al. 2003, Dolman and Wäber 2008). Although information in Australia is limited, there is increasing evidence that deer are causing impacts on natural environments (Davis et al. 2016) and in Victoria, reduction in biodiversity of native vegetation by Sambar has been listed as a Potentially Threatening Process for the reduction in biodiversity of native vegetation under the Flora and Fauna Guarantee Act 1988 (FFG Act).
Deer populations have increased in the Lake Tyers area (c. 39,000 ha), East Gippsland, Victoria, to levels that are causing concern (Gunaikurnai Traditional Owner Land Management Board 2017). The Lake Tyers area contains a diverse mix of Ecological Vegetation Classes (EVC). Of particular importance is the presence of Littoral Rainforest, listed as critically endangered under the commonwealth Environment Protection and Biodiversity Act 1999 (EPBC Act) known to be threatened by deer (TSSC 2008). The area is comprised of mixed land tenures including public land managed within parks and and game reserves, and private land including farmland and the Lake Tyers Aboriginal Reserve (Gunaikurnai Traditional Owner Land Management Board 2017). Damage to native vegetation in the area is being caused by deer browsing, antler activities, wallowing and trampling (Gunaikurnai Traditional Owner Land Management Board 2017).
Sambar occur at Lake Tyers Park. There is no self-sustaining population of hog deer present at Lake Tyers Park, although hog deer occur in Ewing Morass Wildlife Reserve, and there are low density populations to the west around Lakes Entrance and Boole Poole Peninsula, and to the east at the mouth of the Snowy River, and individuals occasionally pass through the Lake Tyers area (B. Mills, Trust for Nature 2018, pers. comm.). A small number of fallow deer have been observed to the far north of Lake Tyers around Nowa Nowa and also in farmland in the upper Toorloo arm, however, fallow deer do not occur within Lake Tyers Park (B. Mills, Trust for Nature 2018, pers. comm.). Concerns about deer impacts at Lake Tyers are therefore focussed on sambar.
The impacts and ecology of sambar in Australia were reviewed and summarised by Davis et al. (2016). Briefly, sambar are a large deer species (110–240 kg; Menkhorst and Knight 2011), which are generally solitary or form small family groups (Bentley 1998, Menkhorst and Knight 2011). Deer impacts occur primarily through the direct effects of herbivory (Davis et al. 2016). Sambar are browsers to intermediate mixed feeders (Parker 2009, Forsyth and Davis 2011). They stand 1.1–1.3 m at the shoulder (Bentley 1998, Mason 2006) and browse up to a height of 2.5 m (Peel et al. 2005), although they more commonly browse at a hieght of 0.6–1.2 m (Bennett 2008). Sambar territory and marking behaviours can also impact on vegetation and include antler rubbing of trees, antler thrashing of understorey vegetation, creating scrapes (scent-marked patches of bare soil cleared of vegetation with hooves and antlers) and wallowing (Bentley 1998, Bennett and Coulson 2011, Menkhorst and Knight 2011, Bilney 2013).
To address growing concerns about increasing deer impacts in the Lake Tyers area, the Department of Environment, Land, Water and Planning have partnered with the East Gippsland Rainforest and Gippsland Plains Conservation Management Networks and Trust for Nature to establish the Lake Tyers Deer Management Trial Implementation Plan which aims to reduce the environmental impacts of deer. It is proposed that volunteer hunters be engaged to control deer using ground-shooting at a landscape scale. Stakeholders are interested in determining how effective this management approach is for mitigating the environmental impacts of deer, and monitoring of the size, distribution and impacts of the deer population have been identified as priorities to inform control programs (Gunaikurnai Traditional Owner Land Management Board 2017).