In 1978 the Australian Deer Association employed a Game Biologist, Max Downes, to plan and advise on the management of sambar in Victoria as a sustainable recreational resource. One of his first recommendations was to record the diet of sambar in the wild. Working under the guidance of Max, I collected the field data, identified the plants eaten by sambar and wrote a summary.
In that summary I drew several conclusions based on field observations. Two points that I would like to revisit are:
- Sambar rarely take more than a small number of mouthfuls from an individual plant.
- Sambar are attracted to blackwoods in August.
This discussion is based on further observations around blackwood (Acacia melanoxylon) but is also applicable to several other species such as wild cherry (Exocarpos cupressiformis).
Since my initial study there have been a succession of fires in 1998/9, 2003, 2006/7, 2009 and 2013 which swept through much of our Victorian sambar forests. As every experienced hunter knows, the bush has changed dramatically since the fires and no longer looks as it did prior to these fires. As the forest regenerates it will continue to evolve and it will change again. It will not be as we remember with some areas undergoing significant change. As an example; successive fires have replaced forest with grasslands in areas of the Alpine National Park.
The severe fires killed many of the mature blackwood trees. However, blackwood has a strategy for survival - seeds germinate and numerous suckers spring from their very extensive network of roots to form thickets. Most of these seedlings and suckers will die as part of the natural process leaving a small number to reach maturity. This is normal as mature blackwoods do not grow in thickets however there can be several big blackwood trees in close proximity.
For several years now, every sambar stomach content I have examined from the area where I originally collected the field data has contained a large proportion of blackwood leaves. This was not the case in the 1970s. The interesting thing is the presence of leaves in months other than August. The other aspect is that very heavy browse sign is obvious on large numbers of suckers. Distinct browse lines are also present on small trees.
When observing evidence of browsing it is easy to draw a simplistic conclusion that sambar are decimating and killing blackwood. Remember, part of the blackwood post-fire cycle is a profusion of regrowth and a natural die off with a small number of trees reaching maturity.
In the fire affected areas, blackwood is going through its cycle with an abundance of regrowth, these young vibrant plants are a standing invitation to sambar. As the trees mature they will become less palatable to sambar and their food preference will shift, probably back to a seasonal preference in August. When the attractiveness of a food plant changes, sambar will look to other preferable and more available food plants. Food selection is based on availability and palatability. Since the fires, I have noted a shift away from prickly coprosma which I had considered to be the preferred and staple food source for sambar in the study area. The only constant I have observed over time is change. When it comes to food and habitat preferences, sambar, like all herbivores, are influenced by the seasons and availability.
There is one more variable to consider - deer numbers. Sambar numbers are now at an all-time high in some areas, placing a higher demand on edible plants than when I did my survey. In the 1970s low numbers of deer appeared to have a negligible impact on the flora. There is a point when unrestrained deer numbers will have a negative impact on the environment and the question is; when will this happen? When the environment can no longer support an overly large population of sambar, the population will decline. As that happens, body weights, antler quality, reproduction and survival rates will fall.
With proper research and positive management practices sambar numbers can be maintained at an acceptable level for the deer hunter and the environment. It’s called Game Management and a sustainable harvest. It won’t happen by itself, it requires dedication and influence to make it happen.
My question above was ‘Blackwood did I get it wrong?’ No, I don’t think so, times and the bush have changed, especially after the fires. Sambar have adapted and taken advantage of the change. We as hunters must adapt and take advantage of the opportunity by shooting more hinds, pushing government to become involved in research into this species and by promoting effective game management. The alternative is an inevitable decline and the label pest instead of ‘Australia’s Greatest Game Animal’.