Could? Yes. Needed? Unlikely. The shrimp have an extremely low bioload when compared to fish, so as long as they get enough oxygen, heating and lighting (for the plants), they should be just fine. I'm actually thinking about doing something like this at work with a vase type thing I found in one of the unoccupied desks.Cool idea! Couldnt you get a mini filter?
http://www.petsmart.com/product/index.jsp?productId=3523858