Not having any "neighbors" is Australia's biggest asset.
You can't walk in from New Zealand. But then again, Indonesia is pretty close for comfort, as is China. I'm not certain of migratory bird routes to/from Australia.
Do you remember seeing that thread a few days ago that showed a picture of that huge dust cloud leaving Africa on the way here? What will that bring us?
Yes I do. I wonder where it's at now...
I don't even want to hazard a guess as to what it's carrying.