Joining parks in Dragonvale
Solution 1:
There is currently no way of doing this. My partner has this same problem and just keeps playing her "accidental" park.
You will either have to keep playing the park you accidently created or just bite the bullet and delete it.
If you do choose to delete your accidental park, you will still be able to get the same dragons in your main park with a bit of patience (they will have different names though).
It's an unfortunate situation to be in but at least the option to keep both parks is there (if you really want to keep those dragons), even if it does take up a bit more of your time.