What is your position?
Are the new hires doing the same job as you?

If you work a highly specialized position that is in less demand because of the economy, then a cut in hours is inevitable. This could be the other way around too. If you lack the skills necessary to work these positions, then you obviously aren't going to get hours in that department. If these people are doing the same work you are, then it is strange that the manager is hiring more people.

Speak with the manager and express that you are willing to be cross trained and pick up more hours doing other work around the store.