I'm having an "akshually" moment here. For what it's worth, the Tragedy of the Commons refers to over-exploitation of material resources that are held in common by a community, like public grazing land in Hardin's famous essay. That can't happen in a libertarian system, because there wouldn't be any commons; all of the land would be privately-owned.

The closely-related concept that plagues libertarian systems is the Free-Rider Problem, which refers to people not paying the cost of a public good, which is defined as one that is non-excludable (can't stop people from using it), and non-rivalrous (use or benefit by one person doesn't prevent use or benefit to anybody else). A classic example of a public good is a lighthouse. Any ship can use a lighthouse, even those that don't help pay for its maintenance. The incentive is not to pay, so public goods are the things that every successful society has to re-invent taxes to pay for.