I'm happy to announce that I have at least one toad living under my deck. That's the sign I have a healthy garden.
Their diet is insects. In your garden the toad is quiet during the day. In the evening it starts croaking.
I had toads at the farm and frogs as well in the pond. I had lots of small garden snakes that eat insects as well.
When the forest I planted reached a certain height, I noticed ants building a hill. Eventually it was about 3 feet tall and full of activity. I asked my friendly forester if I should do anything about it. He told me the anthills are the sign of a healthy forest. Eventually there were about three or four big hills. The ants would be active for a while, and then all of a sudden the ants would abandon the hill and move someplace else. They help decompose the debris on the forest floor which enriches the forest soil. I miss my florist.