Have you ever lifted mulch from the soil or around compost and seen hundreds of tiny creatures springing up, like they were riding on tiny pogo sticks? They were probably springtails, members of the Class and Order "Collembola". If you catch one of them and examine it with a ten times magnifying glass or microscope, you will see that it looks just like a tiny shrimp, with a grey or whitish body. It carries its tail under the body, but when disturbed it flips itself into the air with the tail, springing a surprising height and distance for its small body size. There are several species, some only one or two millimetres long and mostly less than 6mm in length.
They may be found where there is a large amount of decaying organic matter and adequate moisture, including around sprinklers in mown grass, in composts and leaf litter.
I have never seen damage from these creature, they are in fact a very valuable part of the detritus chain, breaking down organic matter. John Dengate, usually a very reliable source, says in his Australian adaptation of Klein and Wenner's book, Tiny Game Hunting, that they can nibble the edges of plants, but the damage must be negligible. He suggests they can be damaging if they get into mushroom kits, which makes much more sense to me. Don't put your mushroom kit in a place where there are lots of leaf litter, and if you need to, he suggests trapping them between sheets of damp tissue paper.
I like to find Collembola, as a sign that the detritus chain is working well. If they ever become a pest for small seedlings, just scratch the mulch back a little. The springtails stay well under cover and will not venture out to feed, even a short distance. More than likely they are blamed for damage actually caused by difficult to find nocturnal animals, because the springtail is more visible.