Allow users to edit just the vocabulary that belong to them?
The Taxonomy Delegate module (http://drupal.org/project/taxonomy_delegate) and the Vocabulary Permissions (http://drupal.org/project/vocabperms) let you delegate administration of a taxonomy to a role, but they do not do it for an individual user. You might be able to write a custom module from here, but what you're proposing goes a little against the role-based permission architecture. My search didn't seem to find one that does exactly what you want.