Red deer in Australia, how do they do?

Australia has unique flora and fauna, but the natural environment has been severely altered since European settlement in the 18th Century.  When managing introduced vertebrates one of the most basic questions to answer is what is the best method to estimate abundance of a particular animal species in a particular environment?  This question is very commonly faced by wildlife ecologists and land managers worldwide on a relatively frequent basis.  The choice of method is often not only limited by the particular species and environment, but also by the available labour and research budget.

Six species of deer are established in Australia.  In our study, now published in WildlifeBiology, "I just want to count them! Considerations when choosing a deer population monitoring method" we set out to estimate the abundance of red deer (Cervus elaphus) in a sub-tropical environment very unlike their native range.  To do this we trialled four commonly utilised methods: distance sampling, aerial survey, spotlight counts and faecal pellet counts.

The sighting boom as viewed in the aerial survey and Helicopter used in aerial survey with sighting booms attached.

Our study showed that for our particular circumstances, spotlighting was the most efficient method.  We also found that deer numbers were high at the study site, and the population stable.  There are always trade-offs when choosing a method to estimate a species abundance and we offer some projections of the expected labour input  vs. precision for similar situations as we encountered to help ecologists and land managers choose between popular methods. 

Researchers counting faecal pellets.   A young stag displaying “eye-shine” whilst spotlighting.

Matt Amos and co-authors

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