Survivorman

So I was watching Survivorman a few nights ago and Les Stroud said something interesting. He was on some sort of tropical beach somewhere and the place was teeming with life. He commented that finding food there was sure a lot easier than when he's been marooned in desolate parts of Canada. Could it be that food just doesn't grow as well where it's super cold? I think I'd rather live where it's warm.