Environmental impacts
Victoria’s biodiversity is impacted significantly by feral deer; indeed the collective impacts of feral deer can disrupt the overall viability and function of ecosystems and landscapes.
Deer have invaded our finest natural areas, including almost all of Victoria’s national parks from the coast to the high country, including Victoria’s highest peak on Mount Bogong.
They cause substantial damage to native vegetation and ecologically fragile areas by:
- overgrazing and trampling native grasslands and herb fields. This reduces a food source normally available to many native animals;
- heavy browsing on branches of shrubs and trees often leads to plant death. Deer will browse on almost every native plant in Victoria;
- ringbarking trees and breaking small trees through antler-rubbing;
- spreading weeds;
- causing erosion by trampling and creating trails; and
- degrading water quality and destroying delicate ecological communities by wallowing in wetlands and streams.
Feral deer also impact the cost of environmental restoration activities. Grazing and browsing from feral deer can devastate restoration works. Landowners, Landcare and other environmental groups must now invest more and more in structures that protect their plantings from deer. Parks Victoria and DELWP are building expensive deer-proof fences around threatened species and vegetation communities to protect them from feral deer.
Deer also affect natural regeneration after a fire or other disturbances by browsing and grazing delicate regrowth and disturbing unstable recovering soils as their weight is distributed to the ground through small hard hooves.
The impacts are of such significance that they are recognised in legislation.
- Environment Protection and Biodiversity Conservation Act 1999: “Herbivory and environmental degradation caused by feral deer” is listed as a Key Threatening Process as part of the “Novel biota and their impact on biodiversity listing”.
- Victorian Flora and Fauna Guarantee Act 1988: “Reduction in biodiversity of native vegetation by Sambar deer (Cervus unicolor)” is listed as a Potentially Threatening Process. (a Potentially Threatening Process is the highest threat listing in Victorian law).
It is noteworthy that the 1988 listing is now old, and doesn’t accommodate a now greater understanding of new threats and the increase in deer populations of the 4 species of feral deer in Victoria. Nevertheless, it was recognised even then that sambar deer were significantly impacting at least 13 threatened flora species and 12 ecological communities, some of which are threatened, including the Alpine Sphagnum Bogs and Associated Fens community.
According to the Department of Environment, Land, Water and Planning, over a thousand species of flora and fauna would benefit from deer control efforts across the state.
Sambar deer Wallowing in and destroying a threatened Alpine Sphagnum Bogs and Associated Fens vegetation community. Photo: Parks Victoria
