Deer are not native to Australia. They have only been here since about the 1860s. Along with the likes of rabbits, foxes, sparrows, blackbirds and many other species, they were originally introduced into the environment by homesick English settlers, both for sentimental reasons and hunting enjoyment. In the 1970s and ‘80s, deer farming became popular as a new way to generate farm income. As with many boom industries, the bust soon followed and many farmers simply opened their gates and let the deer out.
It seemed for a while that deer were quite benevolent in our landscape: cute little bambis standing by the road verge, quietly nibbling away on the grass with no adverse effects, effortlessly leaping over the fence as we drove by.
Unfortunately, it was not to remain so. We are not yet sure why, but things have suddenly changed over the last two decades. Roadside sightings are no longer rare nor special and we have now had our first deer related fatalities on the nation’s roads. Farmers now find themselves competing with deer on a daily basis. And the Australian environment, especially in the creek valleys, is being trashed.
Deer are known as “ecosystem engineers”. These are organisms that create, significantly modify, maintain or destroy a habitat. Ecosystem engineers can have a large impact on the species richness and landscape-level heterogeneity, especially when such an organism arrives in a new area. This is happening in the Cardinia valley right now, to such an extent that both Melbourne Water and Parks Vic have both started to take serious action to limit deer numbers to preserve the natural environment.
Deer damage the environment in a number of ways. Being browsers, they eat a lot of our native shrubs, such as pomaderris and muttonwood, along with the emerging seedlings of the trees, reducing food sources and nesting sites for native wildlife. When the deer population reaches a certain size this prevents regrowth of the various forest species. They also rub their antlers on the trees, effectively ringbarking and killing them. Unlike kangaroos and wallabies, they are cloven hooved, which means they cause impaction of the ground wherever they walk, leaving hard trails through the bush. In the swampy areas they leave pug marks in the ground or worse, create mud wallows, damage the creek banks, increasing siltation and water turbidity, affecting the fresh water crayfish and the platypus that live on them.
Feral deer have been described as “the most serious invasive problem” in NSW and the ACT. The situation is arguably worse in Victoria. Our environment, still struggling to cope with the impact of feral cats and foxes, and feeling the early effects of global warming, can not afford another threat to its existence.