? on Caster Level for Spell Like Abilities & Mage Slayer Feats from CA?

[JDragon]

A Whisper Gnome (races of Stone) gets the Silence spell once per day as a spell like ability. It appears that this is as a 1st level caster. (the book only really specifies for the other normal gnome spell like abilities)

Now what happens to said Silence spell-like ability if the whisper gnome takes one or more of the Mage Slayer feats from Complete Arcane?

I know it drops his caster level by 4 for each feat he takes, does that then keep him from using the power?

If so anyone know a way around it?

Thanks

 

[Jdvn1]

You might throw in "Minimum 1" in there, somewhere, or you might use the rule: "If no caster level is specified, the caster level is equal to the creature's racial Hit Dice." (quoted from the glossary)