I love this play scene idea, it has so many educational possibilities! Creating a play scene like this and slowly building upon it as you learn more about pond life would make a great unit study. It would also make a fun way to use items found on nature walks and during nature study. As children manipulate and play with the various parts of the play scene, scientific learning can be easily reinforced. This is something that would be both easy to make and store.
The source links above will take you to the original blog where you can learn more about this fun idea!