[dfc]

The skills are "fundamental" because the skills are a necessary condition in order to complete the project.

fundamental :

adj. a necessary base or core; of central importance: the protection of fundamental human rights; interpretation of evidence is fundamental to the historian's craft.

<Special Usage>

affecting or relating to the essential nature of something or the crucial point about an issue: the fundamental problem remains that of the housing shortage.

[eldondev]

So I see from your profile that you're an admitted contrarian, but I'll bite your troll-bait. I think if only 18-20 people have the skill, then it does not qualify as a "base or core" skill. The fact that a skill is necessary to complete a task does not, to me, imply that it is also "of central importance". Feel free to continue trolling on the matter by yourself.