Contributing to a Collective Work
Copyright in your contribution to a collective work is completely separate and distinct from copyright in the collective work as a whole, and vests initially in you as the author of the contribution. And unless you expressly transfer the entire bundle of rights that makes up copyright or of any of the individual rights in the bundle, the owner of copyright in the collective work is presumed to have acquired only the privilege of reproducing and distributing your contribution as part of that particular collective work, as well as any revision of that collective work, and any later collective work in the same series.
Of course, if you sign a contract that requires you to transfer some or all of your rights in your individual work to the publisher of the collective work, you should pay particular attention to whether the transfer is so comprehensive that it prevents even you from using your work for a certain period of time or forever.
I cover these contractual issues in detail in my books Literary Law Guide for Authors Contracts Companion for Writers. This how-to guide answers the most common questions writers ask about publishing, agency, coauthoring, working-for-hire, and other agreements.