Janie, I once read a report on an observation of a certain type of Australian Honey-eater. It was observed that this bird and it's mate lived their whole life near one Grevillia bush. They defended their home from other birds and were totally dependant on it. It's the same for many types of bird and also other animals and insects.
I get so sad about the destruction of habitat by humans who say "The wildlife can go somewhere else". Joy