Why Home Range Matters

We've been doing some interesting work on koala home ranges, but before we get into that we thought you might like to know more about the basic science behind our study!

As in:

What's a home range? 

Well, imagine that someone put a GPS tracker on you,
and then plotted out where you went over the course of a few weeks or months. You might take a couple of long-ish trips during that time, but mostly you'd be moving around between your house and the shops and school and work. 

The scientist tracking you would compile all your GPS coordinates onto a map - where each coordinate would be represented as a dot. When the scientist had a look at where the dots were, there would likely be clusters around your house and the places you frequent most often.

That's your home range. 

Now, there are actually some complicated formulas underlying the calculation of home range. But don't worry - we'll leave that to the people doing the research to figure out. What we want to know is how home range can be used in conservation biology ... and what it tells us about koalas.

Home range analysis is useful because it tells us

a) how much an individual animal moves around

b) where it's going

c) how much it overlaps with other individuals

And this is useful information to know when you're trying to reserve land for the protection of a particular species - otherwise, imagine if you bought and protected a patch of land that included only one home range (that means one individual). Not ideal.

You can also determine prospective dangers for individuals, based on their home ranges. As we'll see for koalas, road traffic is a major threat - and using this method we can determine how likely it is for an urban koala to have a road in its home range.

Finally, an understanding of the behaviour of a species is important in its conservation. Do females share home ranges with males? Do larger males have larger or better home ranges? These questions may seem (to some) rather pointless ... but if you're going to spend taxpayers' money on protecting a species then you need to know how to make the best use of your (often minimal) budget. Knowing how individuals behave is critical to conservation efforts.

Want an example? Imagine you're going to buy a house. You love running, and sitting outside on your deck and drinking coffee and listening to the birds. You love your space.

So, are you going to buy a tiny apartment in the inner city? Probably not. If you take a moment and consider your own behaviour, you'll probably choose something you'll be happier with.

I hope that I've illustrated for you that home range is important. I've been a little wordy here, so I'm going to follow up this article with one about actual data on koala home ranges, from Ami's honours thesis. It's cool stuff - so stay tuned!

Written by Amanda Niehaus, PhD, on behalf of the Koala Ecology Group.