The "Roots of Mana"
The "Roots of Mana" is a location known but to a few select elder dragons, and is well hidden away and covered from prying eyes of all kind, including the vast majority of dragon kind. Its not that those elders are scared of most dragons misuse of the roots, but the fact that humans are becoming more and more of a problem, and any knowledge of these roots could be pulled from their minds with a powerful spell caster.
These "roots" are the heart of all magic within the world, spreading out like veins, or roots of a great tree. It pulses and flows, alive and strong, but weakening at the ends where the humans have access to it. Like pests, they chew at these roots and cause them to withdraw outside of their range. This location has such strong magic that if any unleveled, untrained mind were to dip into this location, corruption would be sure to spread through them. Magic both gives and takes if not well controlled. If anything were to happen to these roots, the mana would die, and the would would be plunged into the darkest age, and death would flow freely in its wake.
Dragons and Magic
Dragons are blessed with the ability to draw and store mana, and control it after they come of age. They don't even need to tap into the roots to control it, they can pluck it from the very air around them and weave it to their use. Most dragons have the ability to use magic to move objects, lift things, create things with invisible hands ect. This helps with the species who do not have dexterous hands. However, each dragon, when coming of age, gains one special "Magic awakening". This is unique to each dragon and is incredibly powerful. Maybe they can weave fire spells better, maybe they can heal. Maybe they use it to travel faster, grow thick protective scales, ect.
Creation Tablet and the Roots of Mana
It was thought to be a long lost magic, but has recently appeared again, though VERY RARELY. Some dragons are against the use of creation tablets, others find it wonderful to be able to bring more of their kind to the world in ways that were long lost. The roots of mana, being a fickle thing, have the ability to use the magic put into these ancient stone tablets and bring forth great dragons of any current species on this island. When the tablet is used, it plucks at the magical strings of the roots, sending out a ripple. Dragons still don't know how far the ripple travels but they are able to use some minor magic to reduce this ripple in hopes for keeping any signs of such magic hidden.
This kind of information would be devastating to the isles if the humans came across it, so all do their best to hide any kind of tablet shards they find, and fully rebuilt tablets are often stored away in vaults protected by magic unable to be unwoven by humans.