The floating Islands are where you can place Habitats, Buildings and Decorations.

There are many to unlock, providing plenty of space for your dragons. Not all Islands are instantly visible; you must unlock all expansions of your current Island to open up the next one.

New Islands come with obstacles, such as: Rocks, Trees, and Bushes. Some Dragon Masters prefer to leave these obstacles as decorations, other prefer to remove them in order to have more space.

Tap on an obstacle and then tap 'CLEAR' to remove it. Different amounts of Gold are needed for this action depending on the type of obstacle.
You can also speed up the removal time with Gems.