There's a fair amount of variety in terms of how long the fruiting body lasts - many more conventional looking fungi only last a short time, some only a few days. Some Corprinus species are famous for literally melting into black ooze just a few days after first appearing. Other gilled mushrooms take longer to entirely disappear - while some woody polypores can last, in some form or another, for multiple seasons.

In terms of these little guys there just isn't a lot to disturb them except me and other microorganisms on the piece of bark. In nature rain, wind, snow and other animald would play a role in eliminating signs of the fungal growth. Now I don't know yet how this particular species even spreads it spores - so it could be it disappears as a result of its own physiology in the coming days. Time may tell.