Last year we added about 80 cu/ft of Kellogg's garden soil.. All of which was completely infested with spores. I had more mushrooms than plants! There were so many, that I didn't see any way of getting rid of them without removing all of the soil and starting over. I need up just leaving them be, as they did not seem to harming my plants.

I'll be curious to see what happens this year. I'm really hoping they don't return. I'll be following this thread for suggestions, just in case:)

It looks like you have a lot of wood mulch down. That and moisture generally allow mushrooms to thrive. The top of the mushroom is actually the fruit and spreads thousands of spores. You can reduce the amount of moisture and it will help eliminate the mushrooms.

I have used bleach on the area with mushrooms and that got rid of them. You can try a fungicide but I've never tried that.

The mushrooms will not harm your plants.