[Farling]

Fatigue gives a -2 penalty to Strength and Dexterity, so your ability score is reduced, so you lose access to any things which require a higher score than your current score.

The penalty from fatigue is reducing your actual ability score, like an ability drain - it is not the same as ability damage, which only reduces the ability bonus.

Adjustments are available for "ability score damage" and "ability score drain", which apply the rules accordingly.

I don't think the Pathfinder rules differ in this context between temporary and permanent changes to ability scores.