Kangaroo management comes full circle at Nardoo

on 25 Feb 2013 

Each year we manage kangaroos by the number at Nardoo. That is, we measure a population/km2 figure and we then reduce that population to a pre-set carrying capacity number. Our volunteer shooters Nick Aagren and Richard Lobb have just completed this year’s quota, which should give the Nardoo grasslands some reprieve from overgrazing.

Actually, Nick and Richard finished just in time, because students from the local TAFE will set up the new measurement transect lines next week. Some thirty students participate in setting up these lines all over the Wedderburn district each March and have been doing so for 5 years. Twenty four 150 metre long lines in all go up, along which they then clear all roo droppings within one metre. That results in 24x 150m2 metre of clean ground. One month later, my DSE colleagues and myself then count the droppings deposited on those cleaned up plots and from that we can extrapolate roo numbers per square kilometre for the entire district. The local Department of Primary Industries then follows up with appropriate culling permits for the ensuing year.

Kangaroos are magnificent creatures. At Nardoo we get a mix of Eastern and Western Greys, which is fairly unique for Victoria. The Eastern Greys are grass eaters and tend to overgraze grassy vegetation types when in high numbers so that weeds can infiltrate much easier. Western Greys are more shrub browsers which mean that an overpopulation of them prevents the full recovery of Nardoo, where the shrubs have suffered particularly hard from 120 years or so of sheep grazing and rabbit damage.

In normal circumstances, when things are in balance, kangaroos are an integral part of the Victorian ecosystem. However, certain man-made modifications to the landscape have caused an unintended explosion of roo numbers. There are no hunters on four feet (dingoes) or on two feet (Aboriginal man) left, and lots of farm dams, in particular on hobby farms, have given our bouncy friends an unlimited supply of water. Improved pastures have given them really good food all year round, even in drought times there are plenty of yummies out in the paddocks and on cropping land. In 2008, at the height of the drought and after 12 years of below average rainfall, the automatic drought mechanisms, whereby the doe ejects unborn foetuses, had not set in. It was a drought for everybody else, but not for the kangaroos. So, our shooting program at Nardoo is another attempt to imitate the natural processes that helps to conserve the ecological values of our reserve.

Our Kanga program has helped us out in unexpected ways as well. Since we are now the most serious kangaroo managers in the district, other landholders, some of them broad acre farmers, are looking at us for advice on pest control and other issues. The leverage we have gained over the last 5 years has been very beneficial and made BHA a party that people listen to when conservation issues are being discussed in Central Victoria.

The TAFE students always ask the curly questions, but it doesn’t take long to persuade them we are doing the right thing. Next Wednesday they’ll be hard at work getting a new round of monitoring off the ground. It’s going to be interesting to find out in April what impact the previous cull has had on overall numbers.
Jeroen.